Class _cIifko:r Booki^ GofyrightN?. r j<^ COPflUGHT DEPOSfT TEXT BOOK OF MILK HYGIENE BY DR. WILLIAM ERNST Official Veterinarian and Director of the Royal Milk Control Station at Munich AUTHORIZED TRANSLATION WITH ANNOTATIONS AND REVISIONS BY DR. JOHN R. MOHLER, A. M., V. M. D. Chief of Pathological Division,' United States Bureau of Animal Industry AND DR. ADOLPH EICHHORN, D. V. S. Senior Bacteriologist, Pathological Division, United States Bureau of Animal Industry With 29 Illustrations and 5 Colored Plates CHICAGO, U. S. A. ALEXANDER EGEU PUBLISHER 1914 <^.. 4> .^H-^ Copyrighted at Washington, D. C. BT ALEXANDER EGER 1914 SEP -5 1914 COMPOSITION, ELECTROTYPINC, PRINTING AND BINDING BY THE ^./-Z> W. B. CONKEY COMPANY *^ *^ Hammond, Indiana 'CI,A37940B ^ Table of Contents PAGE Translator's Preface • ^'^^ Author 's Preface ■ ^^ CHAPTER I. Anatomy. Pathology and Histology of the Mammary Gland 1 CHAPTER n. Physiology of Lactation and Characteristics of Milk in General 16 CHAPTER III. Microscopy of Milk in General 24 CHAPTER IV. Composition of Milk and Its Biological, Chemical and Physical Characteristics 32 CHAPTER V. Procurement of Cow 's Milk ^° CHAPTER VI. Internal Influences on the Character of Milk 62 CHAPTER VII. External Influences which Act Upon Milk 132 CHAPTER VIII. Bacteria in Market Milk; Their Origin and Action 152 CHAPTER IX. Milk Control • ; • ^03 CHAPTER X. Milk Inspection • ^ll CHAPTER XI. Fundamental Principles of Legislative Milk Control. 233 Translator's Preface THE importance of food hygiene in the protection and preser- vation of public health is now generally recognized. Milk constitutes one of the most important foods for the human race, and since its composition and wholesomeness are entirely dependent upon its proper handling, the necessity for a strict supervision and control is obvious. The problem of milk hygiene is very complex and must embody all phases of milk control from the time the milk is produced until it reaches the consumer. In all stages it may be subjected to wilful adulteration and to contamination with injurious and ob- noxious substances. Furthermore, the danger threatens this most valuable food not only from outside sources but also from internal influences, as the milk may leave the animal in the condition of a dangerous product, a carrier of pathogenic microbes. Various kinds of infection of the udder are frequently important factors in the contamination of milk, which would render it dangerous to the consumers. Thus in recent years numerous outbreaks of in- fectious soje throats have been caused by such conditions. It is therefore apparent that in the proper control of the milk supply it is necessary to be familiar with all conditions which may be re- sponsible for an injurious or unwholesome product. The subject is one in which every sanitarian should be thoroughly qualified. Although there are numerous splendid publications available on this subject, they are either too voluminous to be used as text- books or they fail to contain the more recent very important devel- opments made in this branch of public hygiene. The excellent German publication of Dr. Ernst entitled '^Milk Hygiene" meets the requirement of a concise, up-to-date work on that subject, and it is with pleasure that in response to requests from various sources we have accepted the preparation of an English edition of this publication. We did not lose sight of the fact that it should meet with the conditions prevailing in this country and accordingly we Translator's Preface, have iiicliidod much vahial)k^ information from the reports of tlie various Milk Commissions, and other sources. For this reason Chapter X dealing with German laws and regulations has been replaced by Chapter XI which deals solely with the conditions and standards existing in this country. We cannot refrain from expressing our sincere thanks to Dr. H. J. "Washburn for his most valued suggestions and assistance in proofreading the manuscript ; also to the publisher, Mr. Alexander Eger, for his interest and courtesy during the preparation of this volume. JOHN K. MOHLER, ADOLPH EICHHORN. Washington, D. C, July 1, 1914. Author's Preface THE increased importance of milk as human food demands more and more the application of modern accomplishments and experiences achieved by science and practice, in order to elevate the milk industry to the desired high standard. The principal stress must be laid upon production, which con- stitutes a special field of the milk industry, and which is most generally in. need of elevation and improvement. The product will be without reproach only when the conditions of production correspond to the value of this food. In the field of production, veterinarians are the proper ex- perts who must stand by the side of the producers and give them the necessary advice and instruction. Only by the active and ex- pert aid of veterinarians can it be hoped to improve the good-will of the producers ; provided, at the same time, other points of milk hygiene which possess bad features — in spite of the active progress of milk control and sanitary methods which have been noted for many decades — also receive proper attention. In order to be able to offer expert advice a thorough knowl- edge . of milk, its formation, procurement and characteristics, is necessary; likewise, a knowledge of conditions which have an in- fluence upon milk while still in the animal body, and the factors which change this food after its procurement. These points have received the principal consideration in the following chapters. In the plan which I have followed, those questions which treat of the judgment of milk as human food in relation to its chemical contents, were given less prominence. Certain points of this sub- ject have been mentioned only to an extent that was considered advisable for the general comprehension of the subject. More specific questions, as for instance, the preparation of certain milk mixtures for the feeding of infants, the advantages and disadvan- tages of feeding cows' milk to infants, the action of a milk diet in the treatment of adults, etc., are subjects for the ph^^sician. A Author's Preface. special cliapter on the preparation of infants' milk, or certified milk, has been omitted, since the sanitarian can not make any distinction in his jndoment of milk as food, hut mnst remember that milk which is consumed by children of the masses should also come up to the requirements established for any food product from a hygienic standpoint. The chemical and physical properties of milk are only dis- cussed to an extent deemed necessary to instruct the veterinary experts in court cases in judg'ino- physiological, pathological and external influences. Since the chemical examination of milk should be placed in the hands of the food chemist, I have eliminated the analytical examination of milk and the examination for preserva- tives. For this information I would recommend the numerous publications which have appeared during recent times, as for in- stance, the works of Grimmer and Sommerfeld, Teichert, Utz and Barthel. Only those methods have been described which may be undertaken by the veterinarian and which are sufficient for a thorough preliminary test of milk for adulterations. The illustrations are taken partly from the known works of my previous teacher, Professor Dr. med. Th. Kitt (Pathological Anatomy) and from Friedberger and Frohner's Methods of Clini- cal Examination ; some were drawn by myself. The illustrations of apparatuses have been avoided, as they appear in all commercial catalogues. In dividing the subject into individual chapters repetitions, of course, could not be avoided. With the preparation of this small work I desire to show to my colleagues the road which they must follow in order to cooper- ate from a milk inspection standpoint in accordance with the call made upon their profession. A difficult point of milk hygiene lies in the changing conditions of production and not in the control of milk consumption or in the supervision of milk transportation. W. ERNST. Munich, January, 1913. Chapter I. ANATOMY, PATHOLOGY AND HISTOLOGY OF THE MAMMARY GLAND. Development and Gross Anatomical Structure. In the lowest form of mammalian life a group of glandular ducts becomes differentiated from the glands of the skm m the median abdominal region. These ducts exude their lacteal secre- tions upon tufts of hair of the mammary region, from which it is either licked or sucked by the young (duckbill, Ormthorhynchus paradoxus). ,^ t ■ ^ i One of the land duckbills, the spiny anteater (Echidna hys- trix), has lacteal ducts opening within an abdominal pouch formed by a fold of skin of the mammary region in the shape of a pocket, in which the young are protected and nourished during their development. This abdominal pouch is not identical with the tegumentarv wall from which is developed the teats of higher mammals, but it mav be taken as the point of origin of the different forms of teats. In higher marsupial animals the glandular ducts are united into a complex gland with teats which constitute the orifices of the confluent lacteal ducts. In other still higher species the most varied kinds of gland structures are observed with various forms of teat development. Among the higher mammalian forms the evolution of these anatomical structures may be followed during embryonic life. On both sides of the body, between the anterior limb-bnd and the inguinal fold, the milk-ridge develops from a linear thickening of the ectoblast in the form of a ledge- like elevation of the epidermis. Along this milk-ridge a series of at first spindle-shaped, then round enlargements appear, which are separated by absorption of the intervening portions of the ridge. These enlargements consist of masses of epithelial cells which correspond to the anlage, primordium or point of origin of the true mammary gland ot the lowest mammalia. This anlage sinks into the underlying mesoblastic tissue and becomes surrounded by a proliferating integument, which forms an investment for the growing epithelial mass. From this mammary envelope which becomes more or less tlat- tended the fibrous and muscular tissue of the areola and teat are derived. At its base, solid epithelial sprouts grow out from the sides of the conical epidermal plug, later be- coming the lactiferous ducts, while the club-shaped thickened extremities m the further course of their development, form the milk sinus. Subsequently, the central part ot the ectoblastic ingrowth undergoes degeneration and what at first was an elevation, now be- 1 2 Anatomy, Pathology and Histology of the Mammary Gland. conies a depression. From the miilillo of this liepressed area there appears an elevation that later becomes the teat. Ill cattle a single excretory canal enters from the bottom of the mammary envelope (point of the teat), into the tissue (the milk duct), the end of which, the milk cistern, breaks up into the secondary lactiferous ducts. The lower opening of the teat con- tains unstriped muscle fibres which act as a sphincter to prevent the escape of milk. (Meckel, Kolliker, Langer, Bonnet, Profe, Schwalbe, Huss, Gegenliauer, Klaatsch.) According to the number of the glandular organs there are distinguished the oligomasts and the pol3miasts. Cows are nor- mally tetramasts, and usually possess four distinctly separated glandular masses, commonly termed the quarters, from each of which protrudes a long teat. The four quarters are united to- gether in pairs and are arranged s^mimetrically. Between their bases and the yellow abdominal fascia they have a rich layer of fat. The ndder is attached alon^ the linea alba to the yellow abdominal fascia, and to the tendons of the abdominal muscles, by two layers of elastic tissue, the suspensory liga- ment (ligamentum suspensorinm niammarum) which penetrates the udder between the two halves. Although the quarters situated on one side show no visible anatomical separation, injection tests with colored gelatin, and ob- servations in cases of inflammation of the udder in natural and artificial infections have proven that the secretory canal systems of the anterior and posterior quarters are separated in the same way as those of the opposite quarters. These canal systems collect into excretory ducts and terminal tubules and finally empty into the milk cistern, which in its iipper part is greatly dilatecl and in its lower part is more constricted. Each quarter possesses a teat (6 to 10 cm. in length) from the milk sinus of which, the duct of the teat (ductus lactifera) of about 8 mm. in length, passes to the outside. The entire udder is covered by fine, slightly hairy skin, which extends posteriorly and supe- riorly into the escutcheon or so-called milk mirror. The size of the udder varies in the different breeds and indi- viduals. In the sheep and the goat there are two milk glands, each possessing a teat which stands out in a divergent direction from the one opposite. Each teat has one excretory duct. While the teats of the sheep are finely haired, those of the goat are hairless. The blood vessels of the udder are derived from the branches of the external pudic artery and anastomose with the various venous branches, through which the blood flows posteriorly through the perineal vein into the internal pudic vein and finally into the obturator vein. The greatest part of the venous blood flows laterally into the external pudic vein and anteriorly into the subcutaneous abdominal vein, which forms the immediate continu- ation of the external pudic vein and which is known as the milk Pathological Anatomy of the Udder. vein. It runs bilaterally of the median line, penetrates posteriorly and laterally to the xiphoid cartilage of the breast bone into the deeper parts and then empties into the internal thoracic vein. The lymph vessels which are very numerous enter two large lymph glands which lie bilaterally in a depression at the posterio- superior portion of the udder and are known as the supramam- mary lymph glands. The lymph passes thence to the lumbar glands and into the thoracic duct. The nerves originate from the lumbar plexus. The udder is supplied by the internal branch of the ilio-hypogastric nerve, the external branch of the lumbo-inguinal nerve, and the external spermatic nerve. In the goat the external spermatic nerve divides in the abdominal cavity into three branches, of which the median and the caudal branches pass through the inguinal ring to the udder. The cephalic branch passes to the abdominal muscles. The caudal branch (inferior) is purely a vascular branch. The median branch passes to the udder, and ramifies to the milk ducts and the teats. Pathological Anatomy of the Udder. Of the pathological processes which are of importance from a practical standpoint, the inflammations and changes which have more or less influence on the quality of the milk are of special in- terest. The other anomalies will be mentioned only briefly. Not infrequently there may be present in cows supernumerary teats, or supernumerary milk glands, which may be considered as a reversion to early stages in the evolution of cattle. Usually two rudimentary formations occur which are generally situated behind the posterior normal glands and normal teats. These may at times yield milk (Burkart, Dauberton). These accessory glands may also occur between the normal teats. In several instances as many as four supernumerary teats were observed. If the udder is abnormally small in its development or is en- tirely absent, it constitutes hypoplasia or aplasia of the udder. According to Bosetti the absence of the mammary gland was ob- served in a cow two and a half years old. Although there were four, small teats on the skin, no milk was secreted even after the birth of a healthy calf. The milk veins were well developed on both sides. The opposite condition, hypertrophy of the udder, with or without secretion, is most conspicuous in male animals. Pusch ob- served a buck which produced 70 gm. of colostrum-like milk daily, and which possessed nipples 7 to 9 cm. in length. Gurlt has re- ported that the udder of a steer was as strongly developed as in a cow, and produced daily 11/2 liters of secretion. It is known that newly born kids and suckling colts occasion- ally secrete milk for several days (Gurlt, Martin, Hess, Ibel). Schmidt, of Dresden, reported a giant udder with an entirely Anatomy, Pathology and Histology of the Mammary Gland. normal milk secretion, (16 liters). A functional hyperemia in the ])e,^inniiii>- of the lactation period increased tlie four quarters unifornily to such an extent that a day after parturition the udder touched the .ground with its central surfaces. Before and after parturition an abnormal amount of hy- peremia occurs physioloii'ically in the udder (hyperemia conges- tiva). In inflammations the same condition may be present, the capillaries are abnonnally dilated, and greatly distended with l)lood. This condition may result in the exuding- of fluid and the solid constituents of blood. These are known as capillary hem- orrhages. In larger extensions of these liemorrhages they are spoken of as sug'gilations, and when the blood is contained in a sac-like cavity or swelling it is known as hematoma uberis. If in the congestive hyperemia the fluid constituents of the blood pass into the tissue of the udder, it results in edema of the udder. The same condition may develop as a result of hydremia, as for instance after changing from dry to sloppy foods (Bang), or as a result of multiple eml)oli of the blood vessels, or from a varicose condition of tlie veins of the udder. Edema of the udder manifests itself as a soft or tense swellino: of the tissue, which retains the impression of the finder. While the teats usually remain normal on account of their slight but dense connective tissue, quantities of fluid collect in the front of the udder and between its glandular substance and the skin. The edema frequently extends posteriorly to the udder and up to the vulva. In- fections of wounds with the bacillus of malignant edema may result in edema of the utlder. To those engaged in milk hygiene the most important of all pathological conditions of the ndder are the inflammations which result from a reaction of the glandular tissue to any inflam- matory irritant. In most instances the inflammations of the udder are produced by microl)ian infections of various kinds, particularly by poly-bacterial infections. The bacteria penetrate the udder either hj way of the blood circulation or from the outside through the orifices of the milk ducts. In such cases it is spoken of as a hematogenic or galactogenic mode of infection. If the infection results from a mixture of bacteria, and is not caused by one kind alone, the affection is a mixed infection. Tlie infection may result from traumatic conditions when injuries extending into the paren- ch^nma of the glands make the infection possible, or from galactif- erous-traumatic causes when the infectious material enters the milk cisterns upon milking tubes or straws. The infection may take place also through simple contact of the orifice of the teat with the infectious material. Thus the different forms of mastitis, the peracute, acute or chronic inflammations of the ndder may arise, depending upon the character of the infectious material and upon special accessory conditions. The possibility of galaetiferous infection was first experimentally proven by Frank. The character and the varieties of inflammations of the udder were further established bv the work of Kitt, Nopard and Mollereau, Lucet, Bang, Hess and Borgeaud, Guillebeau, Zscliokke, Sven Wall, and others. Pathological Anatomy of the Udder. The principal producers of mastitis are the colon-paratyphoid group, staphylococci, streptococci, Bacillus pyogenes hovis, Bacillus tuberculosis, and the actinomyces. Colon infection and severe mixed infections usually result from galactiferous contact, or after the introduction of milking tubes, straws, quills, cat-guts, and hairpins. Highly acute, inflam- matory conditions develop in the affected quarters, whether af- fected throughout or only partially with parenchymatous mas- titis. Hot, painful swellings of the quarters, with collateral edema Fig. 1. Acute inflammation of the right forequarter with collateral edema. (After Kitt.) of the surrounding tissues, are the associating symptoms of this form of inflammation, which either results in recovery with atrophy of the affected parts of the udder, or with regeneration of the epithelia destroyed by the disease or on the other hand the di- sease becomes chronic and may even terminate with complete gan- grenous and ichorous destruction of the affected part of the udder. In the iDfectious forms of mastitis the supramammary lymph glands may swell to fist -sized nodes. If the process becomes chronic a suppurative softening of the affected parts of the tissue, or a suppurative demarcation of ne- crotic parts of the tissue results. These conditions are designated as suppurative and purulent mastitis respectively. 6 Anatomy, Pathology and Histology of the Mammary Gland. The acute forms of mastitis interest those engaged in milk hygiene but little, since noticeable changes in the milk quickly fol- low the commencement of the inflammation, and the animals soon stop their secretion. On the other hand the hidden forms of inflam- mation are of the greatest importance because the milk is fre- quently almost unchanged, and does not always indicate its ined- ible condition. Such conditions of the udder may vary from a simple catarrh to a purulent inflammation. The manifestations of these forms of inflammation vary to a great extent, and the symptoms may be only slightly pronounced, so that a single clin- Fibriiious form of parencliymatoiis mastitis; separation of quarters plainly visible. (After Kitt.) ical examination may cause a suspicion, but a positive diagnosis cannot always be established. Literature shows that slightly marked swelling of the affected quarters, increased local temperature, nodular formation of the parenchyma, and induration of the glandular tissue, may appear in the most varied forms, sometimes with and sometimes without general symptoms. At the beginning it may be localized around the base of the teats, but tlie hardening of the glands then pro- gresses forward, upward and backward (Sven Wall). Tlie examination of the milk ducts should not be neglected. The mucous membrane of the cistern may have become inflamed, Pathological Anatomy of the Udder. resulting in ulcerations, scar formations or polypoid prolifera- tions, which are difficult to recognize. Sometimes such changes of the teats are characterized by cicatricial contractions (strictures). The udder, which usually becomes affected in the individual quar- ters, may remain either normally soft, or may become somewhat harder in consistence. The yellowish-red, normal color of the cross-section disappears, and changes into a grayish-orange or brownish-gray tinge. The parts which are of a harder and tougher consistence show an increase of connective tissue ; the interstitial connective tissue changes into a bluish-white thickened network. Fisr. 3. Purulent mastitis showing necrotic foci. (After Kitt.) The edema of the skin which develops at the beginning of the inflammation results sometimes in extensive sclerosis, even the parenchyma of the glands being sometimes dislodged by the pro- liferating connective tissue causing the quarter to atrophy and harden. Tuberculosis although almost invariably resulting from a hematogenous infection, appears either in the form of a single focus (tuberculosis uberis circumscripta), or it may be dissemi- nated over the entire parenchyma (tuberculosis embolica dissem- inata), or the tissue may be diffusely affected, becoming infiltrated throughout almost its entire extent (tuberculosis diffusa). These 8 Anatomy, Patholosy and Histology of the Mammary Gland. forms of the disease may be present in combination in the same udder. During the tuberculous invasion nodular indurations of the tissue develop, which hypertrophy and become tense, hard and knotty. The lymph glands usually manifest hard, painless, thick- eiung, and notlular fonnations. Caverns may also develop in tu- berculosis of the udder. Actinomycosis which commonly develops from the penetration of actinomycotic barley beards, or particles of straw into the tissue, or more rarely by embolic infection, may also be produced experimentally by the injection of solutions containing actin- oniyces through the milk ducts. Actinomj^cosis of the udder has been observed in cows by Peterson, Rasmussen, Bang, Harms, and Jensen. Nodular formations, connective tissue proliferations and softening of the tissues, localized or in larger areas, are also ob- served in this disease. Botryomycosis and glanders enter into consideration only so far as the udders of mares are concerned. For completeness, various growths may also be mentioned as anomalies of the ndder, such as tibroma, adenoma, adenofibroma, adenocarcinoma, chondrofibroma, chon- (h-oma, lipoma, sarcoma, angioma, etc., which are dependent on the tissue elements and the character of the tissues of which they are composed. Cystic formations have also been observed. Not infrequently the connective tissue and the subcutis of the udder of cows may show bone formations in the form of liony hooks and plates, (ossificatio plana or racemosa). Parasites have also been found in the udders of cows, namely eehinococei (Behmert and Steuding). For further information see Kitt, Pathol. Anatomy, 1910, Vol. 1, page 280. The author once concluded that a goat affected with adenoma papilliferum uberis was troubled with mastitis, basing this decision upon an examination of the milk, although the secretion contained no speeifie inflammatory agents. The continually increasing quantity of milk was remarkable. Postmortem and histological examination finally revealed the adenoma in the udder. Structure of the Tissue The external skin of the teats possesses neither hair nor sebaceous or sweat glands, and continues as cutaneous mucous membrane into the milk ducts, which it lines up to the cistern. The mucous membrane has no glands, possesses fine folds running lengthwise, and is covered by pavement epithelium w^hich is supported upon a well developed papillary base, and is firm and horny next to the lumen. The papillae are extraordinarily long; they apparently branch near the base, and slant towards the orifice of the teats. This cutaneous mucous membrane of the milk duets continues without demarcation, with the mucous mem- brane of the milk cistern, which is covered by several layers of cylindrical epithelium, and possesses accessory glands whiph are lodged in the connective tissue. The wall of the teats contains bundles of involuntary muscles running lengthwise and crosswise, forming a strong and elastic encasement around the canal of the teats. The supporting structure is penetrated by numerous blood structure of the Tissue. 9 vessels and lymph vessels. Numerous and strong elastic fibres strengthen the dense fibrillar connective tissue of the teats. In order to describe the finer structure of the parenchyma of the udder it is necessary at first to touch on the further develop- ment of the organ from birth until the moment of the appearance of the secretion. (a) Normal Appearance. The milk gland is an organ which performs increased func- tions only at certain times. It does not secrete during the entire Fig. 4. Vertical section through the lower end of the teat canal which is closed by a horny plug (a). life but only when the newly born offspring is to be nourished by the milk. The udder of a virgin animal does not correspond even in its finer structure, with the appearance of a fully secreting udder, and this again varies in its finer structure from a gland which is at the beginning or at the end of the lactation period ; even this is not all, since the microscopical appearance changes in ac- cordance with the condition of activity, where a lobule or only a part of the lobule may be found on examination, depending whether the cell-complex is just forming the secretion or has al- ready discharged its secreted product. The gland of a newly born calf shows but relatively few cell tubes and cell buds, imbedded in connective tissue rich in fat and branching in all directions. These prac- tically form the basis of the glandular ducts and are without alveoli. The end of the tubes is frequently somewhat dilated, or thickened in the form of a club. 10 Anatomy, Patliolosy and Histology of the Mammary Gland. With puberty the alveoli appear in the cow suriouinled ])y strong connective tissue. In older virgin individuals they sometimes show a slight amount of secretion. A considerable increase of the glandular tubes appears only- after the first conception. The tubes become more dilated and branch more and more, forming alveoli, from which other ducts bud out. Although indications of secretions in the cells may not yet be visible, the cavities contain a homogenous or fine granular mass of cells or cell fragments. The gland prepares for the secretion, growing at the expense of the atrophying or expanding connective tissue, until ready to commence its secretion. Fig. 5 Superior portion of the teat canal (a) 'with a reflection of the cutaneous mucous membrane of the cistern (b). The cell lining of the larger glandular ducts is of double layers, as in the cistern, while that of the smaller ducts and al- veoli is composed of only a single layer. The epithelium of the latter appears cubical or flat, while the upper layer of the former is cylindrical; in the deep layer the cells are more cubical and rounded, partly wedged in between the bases of the superficial cylindrical cells. The borders of the cells are sharp and the proto- plasma is clear. The nuclei of the epithelia frequently show mi- tosis, that is, division and multiplying forms. The cells rest on the so-called basket cells and the membrana propria. The basket cells structure of the Tissue. 11 should be considered, according to the investigations of Benda and Bertkan, as involuntary muscle cells because of their appearance and their staining qualities. They probably play a part in the emptying of the glandular ducts and the milk secretion. Blood capillaries, lymph vessels and nerves run in the inter-and intra-lobular con- nective tissue, which is strengthened by elastic fibres, and contains involuntary muscle cells. Therefore, the same tissue elements are represented as in the teats, with the ex- ception of the many-layered pavement epithelium. Fiff. 6. Structui-e of the mammary gland in secretion, Hematoxylin. 1 X 800. (a) Secreting glandular alveoli. (b) Alveoli with dormant cells. At the end of pregnancy the picture again changes consid- erably. The protoplasm of the previously clear epithelial cells of the secretory system becomes cloudy, the nuclei larger, their chro- matin collects in flakes on the periphery of the nuclei, the borders of the cell become indistinct, the cells become swollen, the nucleus lies_ in the center, and the indications of the division by indirect fission of the nucleus appear relatively in groups. Some epithe- lial cells show two nuclei at this stage; towards the alveoli fat globules appear. Leucocytes with which a few eosinophiles are mixed, collect beneath the epithelial cells and penetrating the 12 Anatomy, Pathology and Histology of the Mammary Gland. epithelial layer, separate themselves from the epithelial cells and enter the alveoli, which at this stage contain fatty secretions, leucocytes and epithelial cells in all stages of degeneration. A\'itli these manifestations the gland cell connnences its function. The desquamation of epithelial cells and the cell de- generation disappear; the cellular infiltration of the connective tissue recedes until it is very slight between the now greatly di- Chronic mastitis of cow. 1 X 800. (a) Thickened interstitial tissue. (b) Alveoli. (c) Bloort vessels. (1) Epithelial desciuamation. (2) Colostral bodies. (3) Cellular infiltration. (4) Fatty degeneration and necrosis. (5) Milk concrement. lated and distended glandular ducts. The cells are finely granular on the basilar border, and at times show striation, that is, fine streaks running in parallel directions (bioplasts according to Altmann). The nucleus is large and vesicular in shape; the upper part of the cell is granulated and shows large and small fat globules. This granulation and streaking may be seen, according to Steinhaus and Duklert, at each act of secretion. The fine fat globules collect Structure of the Tissue. 13 into larger ones, which are only separated from the lumen by fine protoplasm, or having been expelled have already entered the al- veoli. With the collection of the secretion these dilate, the cell becomes flattened during the expulsion of its products, and the part lying towards the lumen appears indistinctly bordered as if shredded after the expulsion of the fat. They soon become smooth again, and by the pressure of the alveolar contents and the dilation Fig. 8. C'lronic mastitis of cow. 1 X 90. (a) Healthy portion, (b) Glandular portion with chronic mastitis. of the alveoli, the cells sink and become so flat that the nuclei not mfrequently appear bulged out towards the lumen. After the expulsion of the secretion the formation of additional secretion again commences in the cell, the protoplasm again becomes cloudv and granular, and so on, a continuous change of the form of the cell taking place. During the entire lactation period, but more so in the later stages, manifestations of atrophy of the gland appear, at first 14 Anatomy, Pathology and Histology of the Mammary Gland. commencing at the base of the gland, and finally during the end of lactation in the entire ndder. Epithelial cells are thrown off, the alveoli become fewer, smaller, and irregularly distended, the con- nective tissue increases, and cellular infiltration starts under and between the epithelial layers. The epithelium contains no fat globules, it is sharply bordered towards the alveoli and the pro- toplasm becomes pale. Finally the last remains of the secretions Fig. 9. Acute streptococcic mastitis of sheep. 1 X 1000. (a-1) Blood capillaries. 2. Thrombosis by disseminated streptococci. (b) Glandular alveoli, with clumps of streptococci. (c) Migration of leucocytes into the infected alveoli. disappear, the plasma cells and leucocytes taking care of the resorption. At the end of this process the gland is at rest, and the cow is dry. Of course these processes are not always so schematically uni- form as they have been described. During the entire lactation period, colostrum-forming, and retrogressing lobules may be ob- structure of the Tissue, 15 served; likewise certain parts of the udder may remain in secre- tion during retrogression until storing of the secretion, leucocytio resorption activity and connective tissue proliferation cause them to cease their activity. (b) Pathological Appearance. Any kind of irritation of the gland, such as stasis of the milk, especially in chronic catarrhs and inflammations, may result in the most varied kind of pathological conditions, either in mixed form or individually. The manifestations vary, depending upon whether degeneration and destruction of the tissue, or reparation and recovery gain the predominance. Sometimes desquamation of epithelium, with or without fatty degeneration, occurs together with cellular infiltration of the in- terstitial connective tissue and capillary engorgement as the only indications of inflammation ; or, on the other hand, the changes in the interstitial parts may be very pronounced, while the changes of the parenchyma may be less prominent. The inter- and intra- lobular connective tissue extends forming thick indurations, from which the separated epithelium is compressed to small necrotic nests. In other stages of inflammation the cellular infiltration of the tissue predominates. The alveoli and the milk ducts are plugged up thickly with leucocytes, and dilated with the pus. In highly acute inflammations the rapid breaking down of cells, de- struction of epithelium, serous and cellular infiltration of the tissues even to their dissolution, are the principal manifestations. The ducts and the alveoli are inundated with serous, bloody co- agulated masses. In stasis of the milk, and in all inflammatory manifestations, especially of the acute form, the alveoli contain hyalin and con- crement arranged in layers, in addition to inflammatory cells and broken down cellular products. Chapter II. PHYSIOLOGY OF LACTATION AND CHARACTERISTICS OF MILK IN GENERAL. As already mentioned the udder secretes only in certain lactation periods between births. The lactation lasts under nat- ural conditions in healthy animals as long as the young needs the glandular secretion for its nourishment, and stimulates the lactation by the irritation of the intermittent suckling. Shortly before parturition, or at the time of parturition, the glandular tissue terminates its increase in development, and the milk secre- tion starts and becomes actively established. The causes of the increased cell production during pregnancy, and for the secretion after this time, are variously explained. Nervous irritation from the genitals to the milk glands may by means of reflex action stimulate the glands into activity. That such reflexes on the genitals may originate from the milk gland is proven (Pfaundler). Reflex actions in the opposite way, however, have not been proved (Halbau). It has been impossible either experimentally (extirpation of the lumbar cord) or by accident (fracture of the spine), to pro- duce a complete ''nervous isolation," since as emphasized by Pfaundler, there are still remaining the nervous connections through the vasomotors. However, the re-section of nerves, oper- ations on the spinal cord, transplantation experiments, etc., by Eckhardt, Rolirig, Sinety, Busch, Mirnow, Pfister, Ribbert, Golts and Ewald would suggest that besides the nervous influences, which undoubtedly exist, there must be some other agent which stimulates continuous growth during pregnancy, terminates the same with the end of parturition, and inaugurates the secretion. Hematogenic influences may be readily accepted, as they may be led to exert their action either by the quantity or by the quality of the blood. After parturition the 1iody and the milk gland have at their command great quantities of blood Avhich was previously utilized by the gravid uterus. The plethora which appears at this time may be held responsible for the inauguration of the secretion, after the udder has been rendered ready for action by the increase 16 Milk Secretion. 17 of its growth tlirougli nervous influences. On the other handit has been observed that in other conditions, in which there exist also a diversion of great quantities of blood from the genital parts for the supply of other organs, as for instance after operation on very large tumors in the region of the genital organs, no. secre- tion appears even when the udder is prepared for the secretion. As a matter of fact the secretion may commence before birth, and even in early abortions, or if the fetus dies. At times when the uterus is only so slightly distended that the quantity of blood set free after abortion is hardly sufficient for an effective hypere- mia of the milk gland, the secretion of milk may result (Smety, Kreidl, Mandl). Therefore the explanation that the quantitative influences of the blood may give rise to a stimulation of the milk secretion (Freund), can scarcely be accepted. Consequently the qualitative changes of the blood must be considered as more prob- able factors. Authors have diversified opinions upon this question. While some accept the view that substances are eliminated from the impregnated organs, or by the fetus itself into the blood of the mother by internal secretions, and that these act as stimu- lants on the milk glands, others believe that the factors causing lactation lie in the assimilation of certain nutritive substances. The supporters of the theories of ''stimulation substances" (Sinety, Halban, Starling) take the stand that stimulating sub- stances which cannot be utilized for the cellular growth and cellu- lar activity, contrary to the nutritive substances, cause the devel- opment of the gland during pregnancy, and at the same time pre- vent it from secreting (stimulines, hormones [I stimulate], sub- stances of pregnancy). Development of the gland and prevention of secretion may, of course, be the action of one and the same sub- stance (Hildebrand, Starling), or its development, as long as the growth continues, may retard secretion. With birth the stimula- tion of growth and development ceases, and secretion commences. Contrary to this, the theories of nutritive substances empha- size the fact that the glands at times may start the specific activity without the presence of certain stimulines, probably through nutri- tive substances which are present in the blood at various times. Eauber attempts to explain the activity of the gland after birth by declaring that after the expulsion of the fetus a nutritive material becomes available, which has served prior to birth for the preparation of nutriment for the offspring. While the ex- planation of the author that the lymph cells play the most impor- tant part in this can no longer be considered, still it furnishes the basis for all new theories relating to the action of nutritive substances. These views were streng-thened in 1908 by Schein by the state- ment that during pregnancy the mother animal, in order to meet the requirements of the fetus and of the impregnated organs, en- 2 13 Physiology of Lactation ami Cliarat'teristics of Milk in General. riches lier blood with the so-called "milk producing substances." Pfanndler recommends the designation " offspring- nutritive pro- dncing substances." Since during pregnancy the continuously developing placenta utilizes and consumes these sujjstances for use in the nourishment of the young, there remain for the milk gland only slight remnants, just sufficient to result in the necessary stimu- lation for the cellular increase in the gland. After parturition Avhen the activity of the phieenta is completed, the milk gland takes up the released nutritive sul)stances for its own use (specific af- linity of the substances to the cells of the milk gland), and is stimulated to secretion by the quantity of the disposable material. Sehein's milk producing sul)stances in the blood constitute the initial material for the formation of specific components of the milk, milk sugar, casein and milk fat. The material acquired by the mother, through placental con- tact with the fetus, while aiding in the development of the latter is also of benefit to the activity of the milk gland, whose product adapts itself exactly to the requirements of the young, as far as it concerns the material which the young uses for the growth of its body. If conception again takes place the developing placenta of the new fetus enters into competition with the lactating gland, and draws from it milk producing substances for its own use, whereby the secretion of the milk gland becomes reduced or ended. Influences exerted on the milk gland by oestrum or puberty, and also the impulse of pregnancy, have not yet been sufficientiy explained through this theory. Pfanndler enlarges upon and ex- plains these phenomena by stating that the withdrawal of certain nutritive substances, through the germinal gland, embryo and ovum, and not the appearance of milk producing substances alone, periodically disturb the equilibrum of physiologically acting sub- stances in the blood, and thereby the antagonizers of those sub- stances (the stimolines, harmones of other authors), are enabled to find specific receptors (affinities) in other organs of the genital apparatus. After birth, continuing intermittent stimulation may retain or increase the lactation of the milk glands for a longer or shorter time. Stasis of the milk diminishes and retards the secretion. Rievel opposes Schein's view, since in his opinion it does not explain how udders of animals in which neither pregnancy nor birth has preceded, could start secretion (lactation of milk glands of the newly born or virgins, occasionally even of male animals). According to the author's view these facts would not oppose the theory of nutritive substances. Schein, himself, aims to bring these observations into harmony with his views, and asserts that the newly born ma}^ give a secretion from their milk glands, when towards the end of pregnancy the activity of the placenta is dis- turbed, and as a result small quantities of the ''milk producing Milk Secretion. 19 substances" enter without changing directly into the blood of the fetus, and thence into its milk gland. Sufficient stimulation for the secretion and formation of the so-called "witches milk" re- sults. Schein explains the formation of milk in virgin mammae, or in milk glands of individuals which have passed their climacteric, by the fact that through the stimulation produced by sucking, the secretory cells are awakened from their dormant state and then utilize the milk producing substances in the blood for the perform- ance of their functions. Finally (1910) he concludes that the oc- currence of milk secretions in nullipera and in women who have passed the climacteric, which differs from the gradually inaugu- rated normal lactation as a result of pregnancy, and also the ob- served secretion by the breasts of newly born and of male indi- viduals, represents a continuous secretion analogous to the normal secreting process in other glands, in which the product is as a rule, however, re-absorbed by the glandular elements. In pregnancy and at birth the secretion is increased to the greatest extent, but other stimulants may under certain conditions stimulate the activity of the gland. Duval's more recent observations contain data relative to the occurrence of milk secretion by women outside of their normal lactation periods. It is not uncommon to observe secretions in virgin animals especially when young animals which are present stimulate the udder intensively by sucking. It should be emphasized however that the udder secretion of virgin animals distinguishes itself in its appearance from the milk of mature milking animals ; it repre- sents a secretion which does not even deserve the name of milk. The experiments which were conducted by various authors in support of their lactation theories appear of interest. The experiments of Starling aim to show the presence of bodies in the blood during pregnancy which prevent secretion, in which claim is made that an interruption of pregnancy in rabbits at a time in which alveoli capable of secretion were not yet present, led to a retrogression of the milk gland, while in the later periods of pregnancy secretion was induced. According to Pfaimdler's view the harmone theory could be effectively supported by the fact that an existing secretion may be successfully interrupted or prevented by the introduction of serum of pregnant animals of similar species. The author does not believe that this proof is satisfactory and mentions observations made in a case in which the secretion ap- peared at birth of twins which were born at long intervals, that is, the pregnancy continued after the first birth, yet the milk secretion continued unchecked. Wucherer observed a case in which a sow gave birth to nine, and seventeen days later to six other pigs. At the birth of the second lot the first born pigs were taken from the sow. These continued to thrive, but of the second lot only three remained alive. He emphasizes the opinion that a transitory 20 Pliysiolotry of Lactation and Characti'ristics of ]\Iilk in General. action of blood serum, as used in Pfaundler's experiment, which corresponds only slightly in its composition M'itli the normal blood serum, can never be favorably compared with natural influences in the body. This exception must hold also for the indecisive ex- jjeriments of Starling-, who by injections of juices from rabbit em- bryos, but not with injections of preparations from rabbit ovaries, placentas and mucous mend»rane of the uterus, produced a devel- opment of the glands, and at times a degree of milk secretion. He believes that tlie true cause of the secretion may be found in the chemical changes which are produced by the growing embryo and are brought to the glands through the placental circulation. Ac- cording to Basch, secretion may be establisluMl in the mammary glands of virgin rabbits b^^ injecting them with placental extract (serum of unlike origin, from man), which was so powerful that it also brought on a secretion of milk in mother animals without the intervention of pregnancy. The placental extract could induce the secretion only when the teats of these animals were stimulated to hyperplasia by the implantation of ovaries from pregnant animals. According to the author's observations these questions can only l)e determined through experimentation, when by uniting two female individuals of like species a basic condition is established, by which the activity of the glands of one of the impregnated indi- viduals as a consequence of its pregnancy may be observed upon the other, and the result of the impregnation of the latter on the lactation of the first mother may also be determined, Such experi- ments have already been made by Cristea of Vienna, by celiotomy of a virgin and a pregnant animal, and uniting both by suturing of the peritoneum, the musculature and the skin, the author establish- ing a double individual, united by a broad peritoneal communica- tion. Of eighteen such pairs (rats and rabbits) six remained alive. In the experiments after parturition of the gravid animals the milk secretion also appeared in the virgin animals to which they were united. Cristea therefore believes in a slow transition of a secretion from the gravid animal into the non-impregnated animal, namely by the way of the lymphatics, since there existed no blood vessel union between the individual animals. With this result the hypoth- esis that the changed distribution of the blood after birth pro- duces the milk secretion collapses, since on account of the lack of communication of the blood vessels it is not possible that an in- creased blood supply of the mammae of the virgin animal would result from parturition of the attached animal. It can make no difference whether milk producing substances or substances which are not assimilable and are not consumers of energy (stimulating and inhibiting substances), stimulate the glands to activity. Eecently Basch observed an abnormal birth to one of a pair of twins (the Blazek sisters showing a condition of pygopagus, union of the pelvis and sacrum with a common introitus vaginae, and a common rectum), in which after the birth of a child to one, lacta- Milk Secretion. 21 tion commenced also in the virgin sister. In this instance nervous connections may exist in the genitals of both individuals. Accord- ing to the author's view this case is not an absolute proof of the stimulation of the gland by hematogenic means. The lactation theories may be laid aside, and consideration only be given to the fact that at birth, puberty, pregnancy, at the conclusion of parturition and also in the disturbances of the gen- itals influences are exerted on the milk gland the character and action of which are still uncertain, although the results manifested by the production of milk may readily be observed. Especially typical and striking are the phenomena seen at puberty and during and at the end of pregnancy. Exceptionally a condition may ap- pear outside of these normal periods of the organs in females, and in single cases even in male individuals, which permits the conclu- sion that the glands react to special stimulation. Abnormalities may occur in the anatomical structure of the gland, pathological manifestations in the sense of inflammatory reactions, etc., may also be observed, and exceptionally the usual functions may be present or may develop, without their being accompanied by gross anatomical changes of the gland ; these however are usually pres- ent at the same time. These influences on the gland originate partially in the gravid genital organs and the fetus; in other instances the germinal glands and the disturbances of their functions are the cause of these influences. Such influences may be classed according to the impulses which lead to glandular activity, as follows (Halban) : 1. Embryonic impulse — action very transitory — ^mastitis neonatorum — witches milk. 2. Puberty — lasting effect — development of the gland. 3. Oestrum — action rapidly transitory — ^hyperemia, inter- stitial hemorrhages, disturbances to physiological lactation, secre- tion. 4. Impulse of pregnancy — lasting between parturitions. Lactation may be sustained for a long period of time by the regular drawing of the milk, and ceases in healthy udders only when after frequent and absolute stasis of the milk (after about eight days), the tissue becomes affected by inflammatory irrita- tions (absorbtion and change of the condition of the epithelium), or when the animals are soon to give birth to young. If no re-im- pregnation takes place the lactation period may last longer, even from one to two years although not to an unlimited extent. The activity of the gland may be retained for a long time through the sucking of the young, stimulation by milking, or artifical with- drawal of milk. Frequent periodical and complete emptying of the milk cis- terns acts favorably on the amount produced. In the cow two to three milkings per day are sufficient to retain the udder in secretion. 22 Physiology of Lactation and Characteristics of Milk in General, The milk formation occurs between the milking- periods and during- the milkings; therefore of these two periods, the first lasts for many hours, the second with more intensive production is com- pleted in a few minutes. The first phase is the work of continued activity of the gland, the second is brought on under the stimula- tion of the sucking, or milking, on the secretory nerves, and as a result of the increased blood supply (stimulation of the vasodila- tors). The capacity of all the milk ducts of the udder represents less than half of the quantity of milk obtained in one milking. According to Fleischmann the volume of the entire udder of a cow with the teats is 6700 c. c. Of this 3000 c. c. is represented by the cavities ; the secretion obtained in one milking may never- theless amount to 7000 c. c. Niiesch substantiates Fleischmann 's statements by an experi- ment; a cow gave daily before slaughter 10 liters' of milk of which 5 . 5 liters was the amount of the morning milking. After slaughter before milking in the morning 2.7 liters of milk could be proven in the ndder (catheterization and calculation of the amount remaining in the udder), which proves secretion during the process of milking. The two phases may be considered as though the glandular cells which tire after the milking gradually recover (increased blood supply) and recommence their secretions. The collecting secretion will increase until a certain relative pressure between the collective quantity of secretion and the tissue with the blood vessels is established, when the secretion is retarded or ceases until renewed stimulation of the glands by milking, emptying, massage, (electric irritation), or stimulation of the central nervous system from milk accumulations causes the milk to till the cavities of the udder again. If the usual milking time is omitted a flow of milk may result, that is the pressure under which the secretion is held finally over- powers the resistance of the sphincter mnscles at the opening of the teats (directly or by reflex), whereupon formation of milk again takes place. Nervous influences on the secretion are exerted by the sper- maticus externus and by the sympathicus. Experiments which were conducted for the study of the ener- vating influences on the secretion produced contradictory results. Rohrig severed the ramus inferior of the nervus spermaticus externus (vessel branch), and observed an acceleration of the secretion, while the severing of the glandular branch (part of the median branch) resulted in inhibition. Eckhard failed to observe any influence on the quantity of milk after the severing of the ner- vus spermaticus externus. Heidenheim and Partsch demonstrated an increase of the quantity of milk from the cutting of the nervns spermaticus externus, but only when strychnine or curare had been administered at the same time (test by Sinety on guinea pigs). Milk Secretion. 23 Although Bagch could not establish a quantitative increase by sev- ering the nervus spermaticus externus, he found qualitative changes (formation of colostrum). Pfaundler concludes from these and other experiments that an action of the peripheral nerves on the development of the gland and its functions, especially from a qualitative point of view, must figure in the consideration, but that these influences have only slight importance. Insignificant as well in their results on the secretion were the severing and re-sectioning of the spinal cord, or interference with the sympathetic system. Basch again observed the formation of colostral milk after re-sectioning of the coeliac ganglion. From this he concludes that the regulating influence of the nervous system exists through reflex action, especially from the sympa- thetic, but that at the same time the gland is also capable of independent secretion. As a matter of fact far reaching influences of a nervous character are observed. 1. Psychic influences. 2. Eeflexes, which are caused by local stimulations (sucking — ^milking — electrical stimulations, etc.). 3. Eeflexes from the genital region. These points are only briefly mentioned here, since the various conditions will be discussed in subsequent chapters, when consider- ation will be given to the quantitative and qualitative changes which appear under varying influences. An active part in the emptying of the milk from the cisterns, and in the passage from the upper part of the duct and alveolar s^^s- tems, is played by the sucking and pressure exerted during the milking (pressing outwards, sucking from the gland), massage of the udder (pressing out into the cistern), the contractility of the tissue (elastic fibres, involuntary musculature, filling of the blood vessels), and the vis a tergo of the newly formed secretion. Chapter III. MICROSCOPY OF MILK IN GENERAL. If milk is examined tlirougii a microscope one chiefly sees nnmerons small fat cells floating in the fluid or milk plasma. These will be considered later, but at first the cells and cell fragments originating from healthy and affected udders will be discussed. Between the milk globules, by which term the small fat droplets are designated, bodies may be seen which are hard to define unless stained. After special treatment, however, they may be readily recognized as cells or their fragments, or as a precipitation of soluble or suspended substances. Since the external skin of the udder, and the lining of the milk passages and milk secretory ducts in the udder are of similar for- mation, we naturally are only concerned with the upper layers of pavement epithelium, cylindrical epithelium, and the deeper cubical epithelium of the terminal ducts and alveoli, and only in severe tissue changes would cells of other parench^niiatous parts appear in the milk. Naturally in such an actively working organ, even in a physiological normal condition, leucocytes of the most varied kind, and even red blood corpuscles may be found. In cases of special stimulation from physiological or pathological causes, the resulting cell mixture may be of a most varied character depending upon the location of the stimulation, and its quality and duration ; hence at times certain leucocytes, and again reel blood cells or epithelia, may predominate in the mixture. 1. Cells from compound pavement epithelium. Following the intensive manipulation and stimulation of the teats by milking, the appearance of cells from the upper layers of the pavement epithelium of the outer skin, and the milk duets is natural. As a matter of fact in the fresh milking periods during which irrita- tion from the extraction of the milk is especially evident, the milk always contains fine folded platelets of round, oval, or irreg- ularly distended and curved borders, which frequently when folded in several layers, appear as small clasped cysts without special structure. These bodies have been described by Winkler, and were con- sidered by him as indications of pathological changes. The author 24 Cellular Content of Milk. 25 took a stand against this view of Winkler, as he had observed them in the milk of entirely healthy animals, but not until the present time has he been able to offer an explanation of the nature of these bodies, designated as "skinlets" or "shell." They represent desquamated cells of the stratum mortificatum of the pavement epithelial layers singly or in groups. Although usually no parti- cular structure is manifested yet in single instances typical flat, round nuclei can be seen. If the teats of a slaughtered cow are taken and the cistern and milk duct are carefully cut open, and from the surface of the milk duct a small quantity of the cellular layer is scraped Fig. lO. off, an examination by the usual method discloses the typical "shells." 2. If cells from the cistern are prepared and examined, elongated or oval, or quadrangular cells with oval nuclei, frequent- ly elongated at the base, will be found, singlj^ or in groups. Single fat drop- 1 e t s may frequently be seen in the plasma sur- rounding these cells. Sim- ilar cells may also be found in normal milk. They are usually single, although sometimes united in groups arranged like flow- ers. In stimulation, which brings on a desquamation from the mucous mem- brane of the cisterns, or from the parenchyma in catarrhal conditions of the milk passages, they of course appear in masses. Such reactions occur in the cistern for instance as a result of the so-called kneading. 3. Cells from the secreting milk ducts and the alveoli, ap- pearing large or small according to the quantity of fat globules collected in them, often become tremendously distended and bloated (foam cells). Their structure is mostly honeycombed or mulber- ry-shaped when they contain fat ; without fat the cell is surrounded with only a narrow'border of protoplasm. The nucleus is usually in good condition. Film of sediment from milk of a fresh milking cow. Cells from the stratified layer of pavement epithelia of the teat canal. Thionin. 1 X 1000. 26 Microscopy of Milk in General. Fi-. 11. These cells are tlie lar^e colostral bodies. They are in their entire structure and in their stainino- eharacteristic epithelial cells and not leucocj'tes; the amoeboid movements observed in them, if these observations were beyond questioning, do not prove that all colostral bodies represent leucocytes. This point will be again taken up during the discussion of colos- trum. While such cells only appear occasionally in ripe milk they are extremely numerous at the beginning and termination of secre- tion, and in pathological processes, in the latter especially in sul)- acute and chronic forms, butnotin peracute and acute inflammatory conditions of the paren- chjqiia. Such cells may occasionally be noted collected in groups. The author believes tliat their appearance in masses in the milk, that is, the condition increas- ing the expulsion of these epithelia, results from the fact that each cell, which in its singu- lar activity precedes or follows the other cells of the union, becomes desquamated. It does not correspond func- tionally, with the other cells, and is therefore removed from the rows of cells which are de- veloping for a definite purpose or are working for that purpose. Only Avlien uniform work is performed by all of the cells working in unison, and bringing about a uniform condition, will the organ cease to free itself of incapable elements. In inflammation the inflammatory irritation and its consequences soon drive the cells to overproduction. At other times it paralyses or destroys them, even before the formation of milk, depending on the duration of the inflammation. The form of the epithelium varies in accordance with the con- tent of fat. The collection of fat is not the result of fatty degenera- tion, but is produced when the cell is thrown off before its time for secretion, or while still capable of taking up material and produc- ing fat but without strength for the separation of fat. Therefore Cells from the lining membrane of the wall of the cistern. Sediment in catarrh of the cistern. Thionin. 1 X 1000. Cellular Content of Milk. 27 Fig. 12. such cells may be found even in the epithelial groups, which is an additional proof that they with certainty represent epithelial cells. The cells are from 5 to 25, even to 47 /* in size (Schulz). Not infrequently 2 to 3 nuclei of oval or roundish shape are present. The author has never observed more than one nucleus, and be- lieves, with Popper and Schulz, that the appearance of more than one nucleus results from two cells lying on each other, in which case the cell thus formed may appear to possess two or more nuclei. Migrated macrophages may also simulate a polynuclear appearance. Not infrequently epi- thelial cells are thrown off, with a single large fat globule in the body of the cell, known as ' ' seal-ring cells. ' ' In such cases the fat glob- ules have a ''moon" or ''cap" appearance. 4. Leucocytes of all forms are frequently met with in milk such as mononuclear basophiles, eosinophiles, polynuclear basophiles, acidophiles, or cells with neutrophilic and eosinophilic granules in the protoplasm. If the polynuclear cells show no nuclear bridges, they may be found with % or more spherical shaped nuclear granules ( spherical gran- ule polynuclear leuco- cytes, Babs.) The nu- cleus is usually in the shape of a ribbon, or clover leaf, or heartshaped. The protoplasm usually contams fat globules, which in stained preparations appear as fine vacuoles. The lymphocytes are small cells with round nuclei and a verv small border of protoplasm. According to Schulz they never con- tain fat. Large mononuclear leucocytes are also supposed to be present m the milk. If they gorge themselves with fat thev are filled to their fullest extent, and can no longer be distinguished from fat-containing epithelial cells. 5. The red blood cells may be seen as small, round or thorn- Sediment in milk of a cow after milk stasis. Numer- ous desquamated epithelia, among these an "albu- mmophore," and polynuclear leucocytes. 28 Microscopy of Milk in General. apple shaped bodies, witli metachromatic staining substances. They may be readilj'^ recognized as erythrocytes. 6. Degeneration of these various kinds of cells may result in the finding of the most peculiar formations. The protoplasm of the epithelial cells becomes shredded ; the nucleus splits up and eliminates its chromatin into the plasma in the form of dust or flakes. It diffusely passes into the cell pro- toplasm, which appears darkly stained, and in the place of the Fiff. 13. ^Mf The formation of large colostral spheres and desquamation of "seal-ring cells." 1 X 800. nucleus a pale vacuole appears. If the breaking down continues there may appear a disintegration of the cell and of its nucleus into small droplets and fragments of roundish appearance, either with or without a lightly stained border around a small darkly stained center of chromatin (Heidenheim, Colm, Popper, Schulz). These chromatin flakes are probably identical with the so-called free nuclei (Michaelis), which were also observed by Lenfers. The flakes which result from chromatolysis have been des- Cellular Content of Milk. 29 Fisr. 14. ignated up to the present as "Nissen's Globules." According to Ottolenghi they are derived either from leucocytes or from epithelia. If fat-containing cells break down in this manner, fat globules in the shape of grape-like bunches, and single fat globules result, which are united by a mesh of fine protoplasm, or they are sur- rounded in the form of a moon by a narrow border of protoplasm, which crowded to one side rests like a cap on the fat globules. Such moon and cap formations may also result in another way. The leucocytes (mac- rocytes), crowd on to the dead or dying cells, eat their way into the cell bodies and establish in the more and more distending cell actual lacunas, in which the de- vouring leucocytes lie. The remains of the pro- toplasm and of the cell and nuclear membranes float in the shape of caps and moons in the milk protoplasm until the swelling or further breaking down converts them into spheres or globules. At the same time of course the mac- rocytes may t h e m - selves degenerate in the cell, and no longer pre- sent a recognizable nu- cleus. In such cases its respective lacuna con- tains homogeneous, sharply circumscribed proteid globules. The author consi(]ers these epithelial cells which have been destroyed by macro- phages, as identical with the albuminophores of Bab and Schulz which "they described as large lymphocytes, (15 to 20/x), containing fat and 1 to 4 or more proteid globules. _ Besides these regularly formed constituents of the milk, its sediment contains flaky constituents, small irregular shaped coag- ula, which readily tinge with basic anilin dyes, or with nuclear staining substances. Frequently they are without any structure. At times they appear in individual milkings, almost completely dominating the microscopical field. They are the early stages of the corpora amylacea, soon to be descrilied, which apjpear either Budding globules, free nuclei, Nissen's globules, that is cell fragments, in the sediment of cow's milk, 1 X 1000. 30 Microscopy of Milk in General. roiiiul, oval, bean-shaped, or nodular, ranging from very small (1 to 2 /Lt), to an enormous size (5 to 200 m according to Zimmer- mann). These bodies show no concentric formation, or radial stripes. They usually appear during abnormal activity of the gland, and are found in colostrum, in stasis of the milk, in mastitis, in the inactive glands of older animals, etc. Their varied thickness makes active turning of the micrometer screw necessary. These corpora amiilocca (according to Siegert, corp. flava in contra-distinetion from Corp. versicolorata, are tlie ^anie as aniylacea) were seen by Herz, Ottolen>fhi, Iwanoff, and later described by Martin, Lenfers, Winkler and Zimmermann. Wederhake Vvj. 15. Epithelia in different stages of destruction by macrocytes, tliat is so-called albuminophores. 1 X 1000. confirmed their occ-nrrence in the colostrum of women, and compared them with the corp. amylacea of the prostate gland. A section offers the best opportunity for the microscopical study of the nature of these bodies. In preparations of acute mastitis, their development is especially clear. Around small flakes of proteids, possibly precipitated nuclear or cell fragments, layer after layer will be formed until a concrement results, which may even fill the entire alveolus. Lime and salts of magnesium are later absorbed by this basic structure of concentric layers, and fine Milk Concreinents. 31 radiated stripes appear upon its surface in consequence (Fig. 13, Fig. 16 and Table I.). While the alveolar epithelium succumbs to the pressure of the growing eoncrement, and may be absorbed for some time, the eoncrement resists the influences of the organs, and finally is surrounded by connective tissue. Zimmermann states that the bodies may be either in the alveolus or on or under the epithelial layer, and even free in the con- nective tissue. These observations have been confirmed by the author. Tliey stain with metlijdene blue, iodine green, and gentian violet, similar to otlier amyloid substances, but do not give the starch reaction with iodine solution and sul- Fig. 16. phuric acid (Zimmer- mann, and author's ob- servations ) . Wederhake and Winkler claim to have obtained a bluish violet coloration with iodine. The corpora amy- lacea of the mammary glands resist few acids (sulphuric acid, hydro- chloric acid). Otto- lenghi and Zimmermann obtained a solution with pure sulphuric acid. They are therefore pure concrements of se- cretion which form un- der peculiar conditions. Their quality varies, depending on the char- acter of the precipita- tions, which combine to lOrm tnem. Lime eoncrement in the milk sediment of a cow. 1 X 1000. What remarkable significance may be attached to such conditions may be indicated by the views of Herz, who considers them as the initial formation of casein, and those by Winkler, who believes that they change into fat or that they are degenerated epithelium. Leucocytes also crowd upon these bodies, and attempt to dis- solve them just as osteoclasts attack bones. Under their influence, combined with that of the body juices, a destruction, solution and absorption of the concrements may take place, or on the other hand new layers of thickened secretion may form around the old debris, and a new eoncrement develops. This describes, with the exception of the fat globules, the cell elements which may be demonstrated under the microscope, as far as they originate from the udder of the cow. The fat globules will be discussed under the heading of milk fat. Chapter IV. COMPOSITION OF MILK AND ITS BIOLOGICAL, CHEMICAL AND PHYSICAL CHARACTERISTICS. There is very little known with absolute certainty relative to the development of the individual constituents of milk. The theories in this regard are almost entirely hypothetical. It is certain that milk constitutes the specific product of cell activity of the glandular parenchyma, and does not represent a simple trans- udation of the constituents of blood, with a mixture of broken down products of cells (nuclear masses of leucocytes and epithelia, and fatty detritus), nor the fatty breaking down of the epithelium (Reinhardt, Virchow, Skanzoni, Koelliker), nor partial epithelial degeneration of the parts lying adjacent to the lumen (Heiden- hain), nor transformation of leucocytes and lymph cells (Rauber). None of these is the basic pheonomenon in the formation of milk, but it is due instead to the assimilating activity of the cells, which send their secretion into the lumen of the cell tube (Ottolenghi). A breaking down of cells of course occurs to a greater or lesser extent, in accordance with their increased activity, and therefore the milk contains cells and cell fragments in varied quantities, without this throwing off of cells or breaking down of cells having anything to do directly with the secretion proper. The throwing off of useless material, and its natural replacement by functionat- ing elements are only signs that the organ desires to maintain itself in a condition capable of continued secretion. Our attention has previously been directed principally to the functions and activities of the milk gland from a physiological point of view; the morphological condition of the udder and some con- stituents of the secretion have also been noted. In this chapter the chemical qualities of the milk will be considered, as far as this is necessary for the most ordinary conception of these properties. The quality of the milk — in the liroadest sense — adjusts itself to the requirements of the young. The milk gland offers it nutri- tive and protective material in a form which most favorably meets the requirements of the off-spring. In orcler to give only a few examples attention should he direfted to the estah- lished facts, which show that there exist ahsohite relations between the time required 32 ComiDosition of Milk. for the doubling of the weight of the young and the percentage of proteids in the milk; between the proportion of certain salts and the ash constituent, and the rapid growth of the young; between the growth of the brain and the supply of proteids and lecithin. Milk consists of dissolved constituents, and this solution con- tains substances in suspension ; in the entire mixture there are also undissolved substances in emulsion. The dissolved and suspended substances are designated as milk plasma, which after coagulation separates in milk serum and coagulum. The fat is present in an emulsion; there are in addi- tion to this several salts, coagulums, cells, etc., undissolved or in a precipitated condition. In coagulation the casein which at first is in suspension, thickens, and carries down the undissolved sub- stances, separating more or less from the milk serum in which the soluble salts, milk sugar, certain proteids, ferments, coloring mat- ter, etc., remain. The principal constituents of the milk, which constitute as well the principal properties of the glandular secretions, are the parts which have received the most thorough study. The proteids. Casein, milk albumen, and milk globulin (traces of lactomucins, and possibly traces of other proteid substances, which remain after acid precipitation and boiling, being known collectively as lactoproteins) are the protein constituents of milk. The fat; the milk sugar. The milk further contains lecithin, sarcin, kreatinin, nuclein, urea and sulphocyanic acid. Nothing is known at the present time of some of these constit- uents, whether they occur originally in the milk, or whether they are only split products, which result during the final production of the various principal constituents, or through bacterial action in the milk; of such substances may be mentioned peptone, ammonia, leucin, etc. Of non-nitrogenous substances milk also contains citric acid, cholesterin and under certain conditions free lactic acid, alcohol and acetic acid. _ Gases which occur free in milk are oxygen, nitrogen, and oc- casionally carbonic acid ; the salts are combinations of the bases of sodium, potassium, magnesium, calcium, and iron, with hydro- chloric acid, sulphuric acid, phosphoric acid, carbonic acid, and citric acid. Principal Constituents. Casein is a proteid especially characteristic of milk, occur- ring almost exclusively in the milk gland secretion of mammalia, in quantities of from 2 to 4 per cent. (It is supposed to occur also in the secretion of the sebaceous glands of mammaha and in the coccygeal gland of birds.) The origin of casein is unknown. It was formerly supposed that it originated from an enzymic change of serum albumen produced by the action of enzyme-like bodies upon the albumen. However, since it has been found that the assertion of Kemmerich, relative to the increase of the casein at the expense of the laetalbumen, after the di- 3 34 Bioloiiical, Cliemieal and Physical Characteristics of Milk. gestion of milk at lilood temperature for several hours was incorrect (Schmidt and Tier- fehloi', likewise that casein is not produced by mixing hlood serum and nuicerated milk gland structure, or milk gland juice and ovalbumin, and es[)ecially since it is known that casein rej)rcsents a luiclear albumin containing phosphorus, the euzymic origin of the casein in the above sense is denied. For a time Basch 's hypothesis relative to the origin of the casein was accepted, namely that the nucleic acid which is set free in the alveoli by the activity of the gland, combines with the transuded blood serum, forming the nucleo-albuniin, the "casein." Investigation of the experiments of Basch by Odenius, Mendel, Levene and Lobisch proved however that Basch 's hypothesis cannot stand. At the present time it must be admitted that the cells of the milk g-laiid break up the proteids into more simple bodies, and then bnild up the casein from these products. The casein is distinguished from other proteids containing phosphorus, as for in- stance from the nucleo-proteids, l>y the absence of the xanthin group, the pyrimidins, and the pentose group. The consistence of casein from various species of animals varies chemically to a considerable extent. By special reactions with casein anti-serum (precipitation, complement fixation), the caseins from different species of animals may be differentiated one from the other. Tn the splitting up of casein into its various con- stituents, quantitative differences in these split products are found which indicate the differences in the individual caseins. The cow casein contains according to C. Tano-1 52.99 Ellenberger .... 53.07 Burow 52.825 Hammarsten ... 52.96 It is insoluble in water and in alcohol, but with bases forms solutions, the so-called caseinates. Alkali-caseinates form opales- cent solutions, while solutions from caseinates of earthy alkalies represent cloudy, milky fluids. Casein is slightly acid, the solution of which with the bases is accompanied by the formation of salt-like compounds. The characteristics of casein are of especial interest, as they give to the milk its well known properties of rennet-coagulation, and easy acid coagulation, etc. Casein is present in the milk as caseinate of lime, in suspended condition as dicalcium-caseinate, which gives an acid reaction to phenolphthalein, and a neutral reaction to litmus. Acid abstracts calcium from the caseinate, the casein being precipitated (that is casein from the milk of cows and other rum- inants) as coarse, flaky material, while the casein from the milk of solipeds and women is precipitated as a fine, flaky substance. This difference in its properties is traceable to the physical condition which is mani- fested by the casein molecule of the various kinds of milk (Fuld and Wohlgemut) ; but it may also be the result of a variation in the quantity of salt and proteid present in the milk. In the presence of di- and tri-phosphates the casein dissolves by combining with a part of the bases, so that the neutral and alka- line phosphates change into monophosphates (Hammarsten^ Arthus). H. S. P. N. 0. 6.81 0.832 0.877 15.65 23.141% 7.13 0.76 0.80 15.64 22.60 % 7.095 0.725 0.808 15.64 22.906fo 7.05 0.758 0.847 15.65 Casein. 35 Casein is also soluble in other salts, but not, or only to a very slight extent in NaCl, Naa SO4, NaNOs, KCl and others. In the presence of an excess of acid the casein which is first precipitated is again dissolved into a syrup-like mass, but may be again recovered as casein after neutralization. Neutral calcium casein suspensions do not coagulate in boiling, but they form a pellicle on the surface. (The nature of this manifestation is not entirely clear, but depends probably on the drying and transforma- tion of the casein into a more solid form.) Casein is precipitated even in the presence of relatively small quantities of acid while boiling under this condition changes it slowly into a body not susceptible to the action of rennet. In over- heating and likewise in boiling and over-heating with small excesses of alkali, casein is split up through hydrolysis. Even under the action of water, casein is split up into a pro- teid body which is coagulated by heat, passes through a filter and is probably identical with whey casein. The latter substance is formed after the precipitation of the cheesy substance, through the action of rennet, and is a mixture of reduction products of the casein originating through the action of the rennet (Raudnitz). One characteristic property of casein is its precipitation by rennet in the presence of earthy alkali salts. The precipitation of casein has no connection with the action of the rennet as such. This may occur even without having precipitation as a result. If for instance a casein solution is mixed with active rennet, and another solution mixed with inactive boiled rennet, then in the mixture con- taining active rennet, para-casein is formed without any action being noticeable. Only after the addition of soluble calcium salts will precipitation of the para-casein calcium result in the glass which contains the active rennet, but not in the glass containing rennet which has been inactivated by heating. In the change of casein by the rennet ferment, there results in addition to the substance designated as para-casein, another proteid body free of phosphorus, with the properties of albumose, the whey-proteid (Hammarsten). The change of the casein to para-casein, and whey proteid may be a splitting up of the casein, or it may depend on a change in the grouping of the molecules, or it may correspond to a change in its physical condition. The action of rennet in the curdling of milk is practically the same as in casein solutions ; however it is influenced by the other (dissolved) substances, by the other proteids and salts, and pos- sibly also by the physical condition of the fatty emulsion. Curdling with calf rennet develops in accordance with definite laws. In milk that has been brought to low temperatures (refrigera- tor) the action of the rennet may be established by subsequent heat- ing; the precipitation, however, will not take place until the mix- ture is heated to 37 deg. C. (Morgenroth.) 3(3 Bioloyical, Clioinic-al and Physical Characteristics of Milk. Coagulation may not always appear if the milk is immediately heated to .TT (leg., which would indicate that some of the rennet is destroyed at 37 lieg. If the same milk is utilized under the same experimental con- ditions, it can be seen that the amount of rennet necessary for the coagulation of the milk is nearly proportionately opposite to tlie leng'th of time necessary for the coagulation to ])e completed; this fact is expressed by Storch and Segeike as follows : "The product from the quantity of ferment and time of coagulation is constant." Each kind of rennet has a certain strength which of course is changeable, and rela- tive for each sample of milk. In strong dilutions of the rennet the action does not corre- spond with the time rule, the time of coagulation becoming continually longer UJito intinityj that is, coagulation finally no longer takes place. The action of rennet depends on the most varied factors, which may either hasten or retard its action and influence the l)recipitation. Acids for instance strengthen the rennet action, likewise earthy alkali salts, while alkalies, albumoses, neutral salts of high- er concentrations, heating of the milk, talcum, caolin, and muci- laginous substances retard the rennet action. Shaking reduces the strength of the rennet if it is in solution. The following data are taken from a work of Smeliansky in order to show the in- fluence of various additions on the rennet coagulation of cow's milk. It appears that: 1. Heating the milk results in retarding the action. The longer the heating lasts the softer and smaller are the flakes. 2. Addition of water likewise retards the action. 3. Mucilaginous substances retard the rennet action from taking place, and the flakes formed aie soft and loose. Barley water esi)ecially influences its consistence while corn water principally alters the time of coagulation. If boiled milk is diluted with equal parts of a mucilaginous infusion and water, the mucilaginous portions coagulate more quickly than the watery parts. 4. The addition of soda solution renders the flakes soft, and retards coagulation. Milk containing 0.5% of soda is entirely prevented from coagulating even after standing for 24 hours. Four per cent of table salt renders the flakes softer. Potassium carbonate acts the same as soda while the other salts respond according to their alkalinity. 5. Milk of lime retards the action ; chlorate of lime accelerates it. If boiled milk for instance coagulates after 6% hours, the time required for coagulation after the addi- tion of Ca Clo is only S to 15 minutes. It causes the flakes of raw milk to become loose and soft. According to Smeliansky, the reaction indicates the character of the coagulation, and the time required for it. Sugars exert no influence. On the other hand Reichel-Spiro have determined a slight retarding of coagulation in the presence of a high content of cane sugar. Cooking the milk retards the process (lowering the acidity as a result of "the loss of COo and precipitation of lime salts, Eaud- nitz). In overheated milk no coagulation or only poor coagulation takes place. The addition of water retards coagulation (Weitzel), likewise physiological salt solution or whey which is free of ren- net (Reichel-Spiro). Hammarsten, Lorcher, Peters, Weitzel, Gerber and Eaudnitz conducted experiments relative to the action of salts on coagulation, the results of which according to Raudnitz may be interpreted as follows : Rennet. 37 1. The cliemical reaction of rennet is hastened by the distri- bution of the rennet and its quantitative relation to the casein, pos- sibly also by elevated temperatures up to an unknown limit. Alka- line earths and acids probably act in a similar manner by activat- ing the rennet. 2. The chemical reaction is retarded : (a) By the destruction of the rennet : temperatures over 41° C, free hydroxylions ; (b) by inactivation of the same: anti-rennet; _(c) by changes of the casein : temperatures over 80 deg. ; formalin. 3. The physical reaction is hastened by higher temperatures, free Iwdrogenions, and the neutral salts up to a certain concentra- tion, especially the salts of alkaline earths. 4. The physical reaction is retarded by reducing the concen- tration of the mentioned salts below a certain point, especially^ of the alkaline earths ; therefore heating the milk and the salts which precipitate lime, and calciumions will produce this result. Higher concentrations of neutral salts have the same effect. It may also be possible that some of the alkaline action should be considered here. It is known that by the injection of rennet into an animal an anti-rennet may be produced. The rennet acting as antigen induces in the body of the rabbit the formation of a specifically acting anti-body, which works against the action of the antigen in the re-agent glass, very likely through fixation. Normal serum also contains rennet-inhibiting substances. The action of the rennet may be inhibited or entirely prevented by the addition of horse blood as has been proved by Hammarsten, and later by Eoden. The same inhibi- tion is exerted on the action of trypsin and pepsin and is referred to as an anti-ferment action of the blood sernm. Blood of cattle added to cow's milk also shows this chai- acteristic (Schern). Inhibition action is traced back to the anti-ferment substances of a specific nature contained in the blood, and the presence of an anti-rennet is considered probable. It should however be noted that Eaudnitz and Jakoby prevented inhibition by neutralizing the serum with acid. The strength of the rennet may be tested in various ways. That quantity of milk is measured which is coagulated by one part of rennet in 40 minutes at 35 deg. Market rennet has a strength of 1:10,000 to 1:100,000 (fluid rennet and solid rennet). Meunier ascertains the quantity of milk which is coagulated by one e. c. of undi- luted gastric juice in ten minutes. Schern employs solutions of rennet (standard rennet prepared according to Morgenroth) of varying density (1:100:200:300, etc). One part of these rennet dilutions is mixed with nine parts of milk, so that milk-rennet dilutions of 1:10D0: 2000: 3000, etc. are obtained. After an action of two hours the samples are placed in the incubator. The dilutions in which coagulation may now be demonstrated give the relative value of the rennet for the respective milk, and if a mixed milk of healthy animals had been used it establishes the " rennet-titer. " it is to be regretted that the standard rennet solutions are not constant, and that they weaken by storing, etc. For this reason it is necessary to establish the rennet-titer before each test on the milk of healthy animals, or on casein solutions. In addition to the rennet of calves, extracts and ferments from other organs of these animals act on milk in a similar manner, such as extracts of spleen, kidney, liver, lung, thymus, intestine, ovaries, testicles and muscles. Eennet from the stomach of a calf is known as chymosin; rennet from the stomach of a hog, and from the gastric juice of man as parachymosin (Bang). Eennet enzymes may also be demonstrated in the bodies of other animals, fish, birds and snails. 38 Biological, Chemical and Physical Characteristics of Milk. Enzymes 'vvith the action of rennet have been found in various plants and parts of plants, such as tlie artichoke, branches of fifj trees, candytuft (Iberis ])innata), yellow mustard (Jsatis tinctoria), etc., also in bacteria (}>roteolytic) and in yeast. The indiviilual kinds of rennets vary considerably in their sensitiveness to various influences. Whereas the rennet of calves is very susceptible to heat, and exerts its action readily in alkaline solutions, the parachymosin is less influenced liy the harmful action of heat, but is jirreatly affected in its action by the presence of alkalies. The rennet enzyines obtained from plants act in an optimal way at high tem- peratures (sykochymas at 65-70 deg. C. for raw, at 85 deg. C. for sterilized milk). Aside from casein, milk contains proteids which are coagTilable by heat. (1) Lactalbumin which is related to the sermii albmnin but is not identical with it (it has a slight optical polarization: — 36.4 to — 38 against — CO.l to — 62.6, Sebelien). (2) Lacto-globulin may be precipitated with the aid of mag- nesimii sulphate. It is contained in milk in quantities of about . 1 per cent, of the total proteids. The lacto-albumin is obtained from the residual solution after saturation with magnesium sulphate and acidifying it, or by almost complete saturation with ammonium sul- phate. 3. Lacto-mucin has been also demonstrated in milk by Storch, Siegfeld, Yoltz and Eosengren, whereas other proteid substances such as albumose, peptone, albuminose, lacto-protein, gelatin, galaetozymase and opalisin, are considered more recently as pro<1ucts of the preparation of other proteid bodies, at least so far as their appearance in ripe milk is concerned. The proteids which remain in the fluid after precipitation with acid and boiling are collected under the term "lacto-protein." The milk fat consists of a mixture of triglycerides, clioles- terin, lecithin, and a coloring substance, and distinguishes itself considerably from the fat of the body and from the nutritive fat by its chemical and physical characteristics. Although the milk fats manifest considerable dependence upon the nutritive fat, as will be seen from the later chapters, nevertheless a transition of the nutritive fat into milk fat cannot be asserted. The same state- ment would also apply to the transition of body fat, although in this instance a closer relationship between the substances must be admitted. It is possible that transitory relations exist, by means of which split up body fat may be converted in the milk gland into milk fat, and thus the nutritive fat takes ])art indirectly in the formation of milk fat after first having been deposited as body fat. It should be considered however, that the specific activity of the cell builds up the fat from the constituents at hand, and utilizes whatever material is placed at its disposition, such as nutritive fat, when such is present, or body fat in emergencies. The ])roduct will approach in its properties the material which has been utilized, but will always remain peculiar to the species of animal producing it. A formation of fat from proteid is possible, as may be seen when cows are fed with substances free of fat, and after the body fat deposits have been used up. It is probable that the carbohy- drates of the food here take part in the formation of fat. Fat Content. 39 The fat which is contained in milk in the form of very fine globules, causes in part the white color of the milk through the reflection of light. The size of the fat globules varies in the milk of the same cow and depends upon the individual, length of the period of lactation, the race, feeding, and upon whether the first, middle or the last part of the milking is examined. According to Woll, D'Hunt, Schellenberger and Gutzeit the diameter varies between 0.8 and 22 /. with an average of 2.2:2.5:2.9:3.6 /^. Variations in the percentage of fat are caused by change of food, etc. These changes also have an influence on the size of the fat globules, and according to Woll the fat globules become larger with dry feeding, a statement which could not however be confirmed by Schellenberger and Pankowsky. According to the investigations of these authors the feeding of green forage, especially clover, produces large-sized fat globules. The length of the period of lactation should be considered since the variations of size at the beginning of lactation are more con- siderable than in ripe milk, in which the milk globules appear more uniform and mostly of medium size. In colostrum they vary from the sizes of dnst to 20/^ and over. Donne and Schulz found that colostrum contains large, broad oil drops in addition to the small and minute fat globules, which show a less uniform appearance and contour, when compared with the usually spherical fat globules of ripe milk. In interrupted milking the size of the milk globules bears a certain relation to the fat content. With the increased quantity of fat which obtain in the milk toward the end of a single milking, the size of the fat globules also become larger (Schellenberger, Woll). With the extension of the lactation period the size of the fat globules decreases, but their number increases. According to Gutzeit and Schellenberger the following values were obtained in milk from different breeds: Size in 1/1000 mm. No. per ec. in millions. Gutzeit : Schellenberger : Voigtlander 2.73 1944 to 4476.9 Jersey 3.5 2.95 2064.1 to 4643.3 East Friesian 2.30 2521.0 to 5911.0 Angus' 2.95 2.20 2886.0 to 6200.0 Simmenthal 2.56 2995.0 to 5210.3 Dessau 3070.0 to 6308.6 Swiss 2.33 4008.0 to 5326.7 Shorthorn 2.76 Montavoner 2.62 Ilolstein 2.58 Breitenburger 2.46 According to Grimmer the number of milk globules fluctuated in 21 tests on three herds of blackish-brown lowland cattle in Pomerania, from 1,330,000 to 3,073,000 per cubic millimeter, having an average diameter of 2.6-3.7/^. The milk globules retain their form through their surface tension and are not surrounded by special capsules which could be considered as membranes, as has been thought by former authors. 40 Biological, Chemical and Physical Characteristics of Milk. Although the milk globules eaunot bo outiroly fiood from jnoteiils l»y washing (eovering the luilk with water and allowing the ^^epaiatioii of fat), the ileuioustration of the remains of juoteiiis cannot be considered as proof of an actual "haptogen ukmu- brane " which must be broken down during the butter-making process, in order to make possible the flowing together of the milk fat, but it does constitute a proof that rem- nants of proteids, even after the most careful washing of the cream, remain around the fat globules. At least it has never been jiossible to demonstrate membranes of the fat globules, neither in boiled milk, in which during continuous heating larger fat cdumps develop, nor in fat extractions (Soxhlet, Quincke, Alorres). Milk sugar is also a specific substance of milk. It is formed in the i>iancl and is found only in its secretion. If sucking is in- terrnpted, it may be present in the urine, from which it immedi- ately disappears upon amputation of the lactating gland, or it may not appear at all when the gland is amputated l)efore the appear- ance of lactation (Sinet, Magnns-Levy, Znntz). After the com- plete removal of the gland in goats and cows, however, a temporary hyperglycosemia and glycosuria appear. If parts of the gland remain, lactosuria results. After the injection of glucose, lactose appears in the nrine (Porcher), likewise after the ingestion of large quantities of dex- trose. Since the blood in the mammary vein before parturition and during lactation contains considerably less glucose than the blood of the jugular vein (Kaufman and Lagne), it may be accepted that glucose has been utilized in the gland, and further that glucose is the material from the constituents of which the lac- tose is formed in the gland. Of the various salts milk contains compounds of potassium, calcium, magnesium, iron, traces of manganese, aluminum, phos- phoric acid, hydrochloric acid, carbonic acid, sulphuric acid, citric acid, fluorine and iodine. Carbonic acid, oxygen and nitrogen have been demonstrated as gases in the milk. Besides these substances, lecithin, cholesterine and coloring matter are present in the milk, besides ferments and substances which are collected as residual substances; these have been pre- viously mentioned. Eaudnitz and Grimmer have recently published compiled arti- cles relative to the individual constituents and chemical properties of milk which contain the collected material of many experimental results, and at the same time show how much is still unsettled in regard to the composition of milk and the characteristics of the substances which it contains. Certain physical characteristics of milk correspond to its chemical condition. These adjust themselves according to the pro- portion of the various constituents, and to the conditions attend- ing the mixing of the different component parts. The appearance of the milk is influenced by the suspended casein and the proportion of fat. Skimmed milk, Avhich is almost free from fat constitutes a non-transparent, somewhat bluish fluid, as compared with the whitish yellow color of whole milk. The ad- Specific Gravity of Milk. 41 dition of alkalies to milk free of fat renders it transparent. Ham- marsten furnished the proof that a calcium caseinate solution which corresponds to the composition of milk is almost as non-trans- parent as milk. The milk becomes less transparent the smaller the fat globules are. This is most strikingly apparent when the fat globules are broken up to dust-sized bodies (for instance through homogenization). The appearance of fresh milk is also influenced by the coloring matter present in the milk plasma and in the fat. It is known that the skimmed milk of certain cows varies considera- bly in color; at times it is bluish white, sometimes more yellowish green, again transparent, other times of a non-transparent whitish color, and also the fat has a more yellow color during the pasturing of the animals than at the time of stable feeding. The non-transpareney as mentioned above is no proof of the presence of fat in the milk; therefore all methods which are destined to establish the quantity of fat or addition of water by the establishment of the whiteness, are of no use, as for instance, Heeren 's pioscope, Feser 's lactoscope, etc. Tf milk is allowed to stand for a time, cream forms on the surface ; the fat globules rise and collect usually as a distinct layer of cream above the milk. The rapidity of the separation depends on the temperature, the size of the fat globules, and the density of the milk plasma. The quantity of the cream is not in parallel rela- tion to the quantity of fat ; it depends on the size of the fat globules. The separation of cream may be hastened and increased by centrifugalization. During separation while allowing to stand, about 85% of the fat rises to the surface, while by a perfectly operating centrifuge the separation of cream may be accomplished up to 0.01% of its M. The specific gravity of the milk depends on the solid sub- stances, the relation of the mixture and the condition of the sus- pended, dissolved, and emulsified constituents of the solid siib- stances. Corresponding to the variable composition of cow's milk it is natural that the specific gravity of the milk should vary. It fluctuates considerably, varying from 1.027 to 1.034 at a temperature of 15 deg. Similar to the impossibility of speaking of milk of normal composition, one cannot speak of milk of normal specific gravity, and even to give average figures would be of very problematical value; but to take such average figures or even smallest values as a iDasis for the calculation of falsification would be a gross error. Milk from many cows would under ordinary con- ditions have a specific gravity of 1,029 to 1,033. The specific gravity is measured, or is calculated from the values of fat contents and solids, according to formulas, which, depending on the milk from certain breeds, or certain localities, show slight variations. This formula made on the basis of the value of the specific gravity of the milk fat (about 0.93), and the solids or dry substances (1.6001), which is quite constant, is according to Fleischmann: 42 Biological, Chemical and Physical Characteristics of Milk. 1000 1000—3.75 (d— 1.2f) In these equations s stands for specilic gravity, d for dry substances or solids, and f for fat. The following- vahies may also be calculated from the fat con- tents of the milk and its si^ecilic gravity. 1. Total solids : d=1.2f+2.665X™^=^^ s 2. The fat-free solids are shown by deducing the percentage of fat from the percentage of the total "solids. 3. The specific gravity of the solids _ ' sXd ~ sXd— (100 s— 100) 4. Finally the fat contents when the solids and specific grav- ity are known : f=0. 833 (1-2.22^2=122 S The values obtained from formulas are of course not abso- lutely correct, but represent the results only approximately with the analytical methods of weights, the fat-free dry substance of the milk is not of absolute constant composition, but varies, so that its specific gravity which is based upon the sugars, proteids and salts, varies more or less from the number which has been accepted by Fleisehmann as the average value (1 . 60). The equations hold only for cow's milk. If milk is freshly drawn, and immediately tested it shows a considerably lower specific gravity (0.0008-6.0015), than after cooling. The milk ''contracts" and becomes constant in its specific gravity only after standing for several hours. The cause of this manifestation is not yet entirely clear. Toyonaga aims to explain it by the fixing of previously uncooled and fluid fat globules, which is the most plausible explanation ; other authors believe that the contraction is the result of a cessation of the expansion of the casein. The density of the milk varies in accordance with the tempera- ture. The maximum (for water at 4 deg.) lies almost near its freezing point, namely at . 3 deg. C. The freezing point of milk is somewhat lower, namely — . 54 to — 0. 57 deg. This is especially influenced by the presence of salt, less by the sugar contents of the individual samples of milk, and it is induced by the relatively constant amount of soluble salts in the salt contents, which is subject to only slight fluctuations in the milk of healthy animals. For the sake of completeness the electrical conductibiiity of the milk should also be mentioned. This varies according to the re- sistance which is offered by the fluid to the current. It fluctuates Polarization of Milk. 43 within wider borders than the freezing point, and is influenced ac- cording to Zanger by general diseases, through local affections of the udder, by estrum, pregnancy, feeding, etc. The conductivity is diminished by the fat globules ; therefore skim milk conducts better than whole milk or cream. The conductivity of the different quar- ters is inversely proportional to the quantity of milk, in milk from different quarters of one cow (Schnorf). The viscosity of milk is a factor which principally depends on the condition and on the quantity of the casein and the fat. Higher temperatures reduce the viscosity, likewise shaking ; quiet standing increases it. The surface tension of milk is lower than that of water (0.053 against 0.075). Of the physical properties the specific gravity of milk and its serum, and the polarization of milk serum, are of special impor- tance for the practical testing of milk (see technique). For practi- cal results, however, the determination of the fat contents is also necessary. As it has been shown the total solids may be determined by the aid of the fat contents and the specific gravity and the fat-free solids may be established by deducting the percentage of fat, these four factors are generally sufficient for the preliminary tests. For more accurate study these preliminary tests are com- pleted by the establishment of the specific gravity of the milk serum, or still better by the ref ractoscope to determine the chlorids of calcium serum, which renders more rapid work possible. This is a method whose satisfactory use in practice has been proven by the numerous works of Mai and Eothenfusser. Publications relative to the polarization of milk were issued by Valentin in 1879, and later continued by Villiers and Bertault, Braun, Utz, Lam, Radulesku, Ripper, Schnorf and others, on ren- net serum, acetic acid serum and milk serum, which had been pre- pared by voluntary coagulation. The given values of the authors varied in accordance with the method of preparation of the serum; nevertheless it could be estab- lished that comparatively uniform figures were obtained whenever the work was carried out under similar experimental conditions. In 1908 Cornalba showed that contrary to the variance in the amount of colloidal substances dissolved or suspended in milk, the sum of the dissolved constituents of milk is very constant. Whereas in samples of mixed milk the sum of the first substances varied between 5 and 8 . 585 per cent, the differences for the total dissolved substances were only 6.05 to 6.25 per cent. Milk serum which contains the dissolved substances, offers therefore constant results in the examinations, the same as the examinations which lead to the establishment of the fat-free solids, which still include the casein. Examinations of serum are therefore of the highest practical value for the demonstration 44 Biological, Chemical and Physical Characteristics of Milk. or establishment of the addition of water, provided that the sornm is always prepared in the same way. Ackennann, Mai and Roth- enfnsser have in their fundamental works, determined tlie practi- cal importance of the polarization of the proteid-free serum, and have proved that with the polarization of the chloride of calcium serum we possess means which are better adapted than any other to the detection of the adulteration of milk by water. Refrac- tion is the most valuable accessory to the various methods of tests of recent times. Ackermann found in 2,800 samples of normal milk, variations in the scale division of Zeiss 's immersion refractometer, from 38.5 to 40.5. Even slight additions of water reduce the refraction con- siderably; the addition of 5% of water results in a 1.3 lowering of the scale division, while 10% lowers it 2.3. According- to Mai and Rothenfusser the original refraction of 39 scale divisions is lowered to a refraction of : 37.9 vrith about 4% addition of water 37.7 a 5% 37.5 I i 6% 37.3 i ( 7% 37.1 i i 8% 36.9 i i 9% 36.7 i i 10% 36.5 i i 11% 36.3 i i 12% 36.1 I i 13% 35.9 i i 14% 35.7 i i 15% 35.5 i i 16% 35.3 I i 17% 35.] i i 18% 35.0 i i 19% 34.8 i i 20% 34.0 a 25% 33.3 i i 30% 32.6 ( i 35% 32. i i 40% 30.9 i I 50% In the establishment of the refraction index of the chloride of calcium serum it was also discovered that it is impossible to estab- lish normal values for the chloride of calcium serum, as well as for other constituents of milk. Mai and Rothenfusser also estab- lished the general rule for milk, that only in the presence of rigor- ous controls of the same origin can the addition of water be satisfactorily determined, and the extent of the adulteration established. Ferments in Milk. 45 The experiments of Weigner and Yakuwa are of interest since they demonstrate that the refraction and specific gravity of the chloride of calcium serum are theoretically of equal value. Mai and Rothenfusser, on the other hand, emphasize the fact that of two theoretical methods of equal value the man in practice has to prefer the method which offers, with the same certainty of the results, greater advantages in regard to rapidity, convenience, and saving of material, advantages which the method of refrac- tion possesses. The investigations of Mai and Eothenfusser prove that the variations in the results of continued tests, from day to day may reach in mixed milk of one stable . 1 to . 55, and in longer periods ( 22 days ) , up to 1 . 0. Changes of feeding have no marked influence. The milk of individual cows failed to show any important fluctua- tion during the time in which the tests of the entire stable Avere made (0.2 to 0.6). More considerable may be the fluctuation between the find- ings of normal milk and the secretion from cows Avith an affected udder, and the variation between the findings of milk from the same animal while healthy, and within 24 hours after the udder becomes diseased. The milk of individual animals with affected udders shows, not infrequently, values which are considerably below the values of normal milk. This has been proved by the work of Metz^ger, Fuchs, Jesser and Henkel, and from the experience of the official milk control station. These abnormal values, however, do not affect the worth of this method, if the results are compared through the use of satis- factory control tests, and confirmed by other methods. Ferments in Milk. Immune Bodies. Milk as Antigen. For the testing of milk special characteristics which it pos- sesses, which may be collected under the name of reaction manifes- tation of ferment action, and for which at present there is still no satisfactory explanation, are of importance. Under the term ferments (enzymes) those substances are included which hasten chemical changes with an explosion-like rapidity (Uexkuell), and without using themselves up they act in relatively minimal quantities. Their activity is inhibited by the products of the reaction. Higher degress of heat and certain toxins (ferment toxins, as for instance hydrocyanic acid) inhibit their activity, the ferments being thermolabile. The author desig- nates as ferments all of those bodies with ferment-like action, with- out consideration as to whether the nature of the ferment is known or not. A careful distinction must be made between original fermen- 4G Biolotiical, Clieinical and Pliysical Characteristics of Milk. tative action and fcrniont-like bacterial activity sometimes taking- place in milk. The original "ferments," the natnre of which is disputed, originate from the blood, or are formed from the cells of the blood and the parenchyma of the ndder. They are either eliminated the same as products of metabolism into the surrounding parts, or they are anchored to the cell and are only set free in the breaking up of the cell (ecto- and endo-ferments). The ferments in their action are destined to certain substances to which they fit, "as the key fits the lock" (Fischer). They act either through hydrolytic splitting, through oxidation, or through reduction. Those ferments are of importance to the milk inspector, where diminished or increased presence or complete absence offers cer- tain conclusions as to various conditions in the udder or in the milk. These are the amylase (diastase), the indirect oxydase (per- oxydase), the superoxydase (catalase) and the indirect reductase ( aldehydreductase, ' ' aldehydcatalase " ) . Besides those mentionefl, milk also contains other bodies whieli are included among the ferments; for practical milk examinations, however, they have little or no bearing. Mention need only be made here of the proteolytic ferment, " Galacta,se," found by Babcock and Eussell and bodies acting like pepsin or trypsin (Jensen, Freudenreich, Spolverini and others). These are only present in very small amounts. Kinase and fibrin ferment have also been demonstrated in milk. The proteolysis could be explained through the presence of leucocytes in the milk. Similar to the proteolytic ferments which cannot be utilized for diagnostic purposes, the lipase and the salol-splitting salolase (the existence of which as a ferment is dis- puted by Desmouliere, Miele and Willen ; the alkaline reaction of various kinds of milk is sufficient to split up the salol) can not be likewise utilized for the purpose of di- agnosis. Rullmann in 1910 proved by the examination of aseptically drawn milk, that salolase is not an original ferment; the author considers the splitting of the salol to be the result of bacterial action. Of the ferments in milk which split up the carbo-hydrates, the amylase (diastase, galactoenzyme), whose action is similar to the ptyalin of saliva splitting up the polysaccharid starch into dex- trose and maltose, is of the greatest interest (Moro). This fer- ment was first found by Bechamp in the milk of women, later by Zaitscheck, Koning, Seligmann and others in cow's milk. One hundred c. c. of mixed milk can be split up b}^ 0.015 to 0.020 gm. of amylase. Amylase is destroyed by heating for 30 minutes at 68 deg. C. (Koning) ; the optimum of its activity lies at 45 deg. C. The substances designated as oxydase and peroxydase exert a special action. They transmit the oxidation either by "activation of the oxygen of the air," (direct oxida- tion) or by abstracting the active oxygen, for instance from peroxide of hydrogen (per- oxydase). Substances acting as reagents indicate their oxidation by the formation of coloring matter. The occurrence of direct oxydase in milk, the action of which appears even without peroxide of hydrogen, is uncertain. Rull- man has found traces of direct oxidation in milk drawn under sterile conditions ; the quantity however is almost nil for practical purposes. The indirect oxydase acts only after the addition of hydro- gen peroxide or other oxygen carriers (for instance super-borates), Catalase. 47 by abstracting active oxygen after the formula HoO.^H.O+O (Jensen). The active oxygen oxidizes the added ''chromogenic" substances, as guaiacol, ursol, paraphenylendiamin, etc., to coloring matter. The peroxydase is injured by long heating, even at the relatively lower temperature (50-60-70 deg. C), and is destroyed at about 75 deg., so that boiled or pasteurized milk may be dis- tinguished from raw milk by the non-appearance of the color reaction. The action of the superoxydase (Raudnitz) or catalase (Loew) develops in a different way. It splits the HoOo according to the formula 2 llo0o=2 H.O+aO, which join to a molecule of 0.. Other authors include the superoxydase with the oxidizing fer- ments, as the freed oxygen is utilized in the body for the oxidation (Seligmann). According to others it is included with reductase, as the action of the ferments on H.^Oo equals a reduction of 2 HoO, and molecular oxygen O2 which passes out without being utilized for oxidation, whereas the oxygen freed by peroxydase is imme- diately utilized for further oxidation changes ; therefore the per- oxydase is an oxidyzing, while the catalase is a reducing ferment (Grrimmer). Original catalase has been demonstrated in the milk of all animals ; it originates in the cells of the milk gland, especially from the leucocytes. It is secreted, but may be set free in the breaking down of cells or may appear bound to the cell. That catalase is derived from the cells (especially leucocytes) is not contradicted by the fact that cream is richer in catalase than skim milk since leucocytes and other cells are also included in the separation of the cream. These conditions were indicated by Friedjung, Hecht and Pallazzi, and later confirmed by Koning. This also explains the reason for the centrifuge foam, rich in leucocytes, giving such a strong reaction. Since the formed elements (cells) are precipitated with the casein, and probably a part of the free ferment is also drawn down with it, milk serum is always poorer in catalase than the original milk. Catalase passes through infusorial earth filters, but consider- able quantities are retained. Light, storage, etc., affect catalase, even it it is relatively resistant. A leucocytic extract, which was kept exposed to the light in the laboratory of the author, showed even after months, an unweakened action to HoOs, while hydrogen sulphide, hydrocyanic acid, potassium cyanide, mercuric cyanide barium nitrate, hydrochloric acid, sulphuric acid, acetic acid, oxalic acid, and potassium nitrate affected its action (Faitelowitz). it appears noteworthy that H3O2 inhibits the ferment in its action, in the presence of excessive amounts of peroxide of hydrogen the terment splits up less H,0. than if the diluted peroxide ofVdro- gen IS gradually added. Heating to 62-70° C. destroys the original catalase in a short time, ihe optimum temperature appears to be about 37 deg. C. 48 Biological, Chemical and Physical Characteristics of Milk. An original "ferment," the nature of wliicli is by no means definite, is Scliardinger's formalin methylene blue reductase, which according to .Tronmisdorff, will be designated as Schardinger's ferment (synonyms are indirect reductase, aldehydcatalase, alde- hydreductase). Fresh milk in a mixture of formalin and aqueous methylene blue sohition (Schardinger's re-agent), is decolorized inside of a few minutes. Smidt explains the action of Scharding- er's ferment by the fact that the formalin changes into formic acid and thereby reduces the methylene blue. The character of its action however is not yet solved. The Schardinger ferment exerts its best action, at Cw to 70 deg. C, it is destroyed above 70 deg. As has already l)een indicated by Smidt and confirmed by Tromms- dorff, Schardinger's ferment is very sensitive. It is injured b^^ small excesses of formalin, and by relatively larger quantities it is destroyed. Romer and Sames established more recently, the interesting: fact that boiled milk ■with 0.3 c. c. of a 1% of ferrosulpliate solution also s'ives the reaction, and this disap- pears again when the mixture is boiled for a half hour. The authors point to the care ■ndiich must be taken in judging' the so-called enzyme reaction, since it is possible, with the aid of simple chemical reagents, to produce similar effects to those obtained in the supposed enzymatic reaction. Very little is known relative to the origin of the formalin re- ductase in milk. This ferment is not in every sample of milk, being frequently absent in milk from an animal whose off-spring is still sucking, and in animals which are just fresh in milk (Schern). It is absent when the time of milking is over-extended, and in stasis of the milk (Romer and Sames), and it does not decolorize, or only incompletely so, in the first part of the milking, better in the middle of the milking, and rapidly in the last portion of the milk- ing. This also corresponds to the relative frequency of fat in milk but no one however has been able to establish a complete par- allelism. The authors conclude from this that the same conditions under which the gland excretes especially large amounts of fat, cause the quantity of Schardinger's ferment to be likewise in- creased. Milk as Antigen and Carrier of Anti-Bodies. Since the fundamental experiments of Ehrlich relative to the formation of immune substances in the animal body, we possess an explanation for manifold manifestations between the inter-action of the disease-producing agent and the animal's power of protec- tion, known as Ehrlich 's theory of immunity. The substances which are formed in the body in the com- l)at against certain invaders are the anti-bodies ; the harmful sub- stances which are capable of stimulating the body to the formation of anti-bodies are the antigens. Antigens may be substances of the most varied kinds ; animal proteid, animal cells, plant cells, plant proteid, living and dead bac- teria, bacterial substances, toxins, etc. The antigens are distin- Antigen Action. 49 guislied by groups, wliicli make possible their combining with cer- tain groups of the cell substances of the body. The "haptophore" groups of antigens under certain conditions fit as a key fits the lock, into the haptophore group of the "receptors," thus making- possible the binding of the antigens to the cell. These terms were applied to these bodies by Ehrlich. _ The simplest way of explaining the mechanism of the antigen action and the anti-body formation is by using toxin as an example, A toxin is an antigen with a haptophore binding group, and a poison-producing group, the toxophores. If the toxin enters the body of an animal it may find groups on the cell to which it fits, the so-called receptors, which bind its haptophore group. If this has been the case the toxophore group exerts its action, the effect of the toxin becomes noticeable and the animal suffers as a result of the toxin. If there are no receptors present for the specific toxin it is impossible for the toxin group to exert its action, and the animal is therefore resistant against this respective toxin. It is possible that as a result of the receptors of the cell com- bining with the toxin, the cell molecule is destroyed. But if the damage is not too serious, the protoplasm is stimulated to produce numerous receptors, — an over-production in fact. As not all of these are necessary for the performance of the cell function, the superfluous ones are rapidly thrown off into the body fluids. If such free receptors combine with the haptophore groups of the toxin, the latter is no longer able to combine with the protoplasm of the cell. These free receptors therefore protect the body against renewed action of the toxin, that is they act as antitoxins, and con- stitute the antitoxic part of the serum. Besides the antitoxins, the action of which lies principally in the neutralization of the binding group of the toxin (anti-bodies of the first order), there are still more complicated receptors, for instance those which possess an active or ferment-producing group ; they are anti-bodies of the second order. Finallv there are anti-bodies of the third order, which are unable to act by them- selves, but must utilize a third body in order to exert an action on the antigen. ^ Immune bodies of the third order become complete in their action, only through the utilization of the complement. These im- mune bodies of the third order possesss therefore a binding group for anchoring the antigen, and a binding group for the complement. They are amboceptors, in contradistinction to the uniceptors of the first and second order. Some anti-bodies resist heating for a half hour at 56 deg. C; they are thermostabile, as for instance the antitoxins, the agglu- tmms, the amboceptors, while others, as for instance the comple- ment, are destroyed at this temperature, as they are thermo-labile. , , . ^^' /^^ instance, hemolytic anti-bodies are produced in a rabbit by treating the rabbit with red-blood corpuscles of another animal, then the hemolytic rabbit serum lo-^es its action by heating to 56 deo-. C 50 Biological, Clieuiical and Physical Characteristics of Milk. The red blooil corpuscles however are again dissolved when to the heated, "inacti- vated" rabbit serum, guinea-pig serum containing complement is adde> *The cow with maximal production stood last year in ninth place. 17 cows pro- duced over 3000 kg. each. ^ The fluctuation is not in fat content alone, but also in the other solid substances. Milk which is rich in fat as a rule contains more of the other solid constituents as well. The proportion of individual factors of the dry substances is variable; in cattle from the highlands for instance, the casein was 76.24% of the dry sub- stance, m cattle of the lowlands it averaged 73.78% (Fischer). ^■f. ^a^^^^i'om the milk of the mountain breeds is generally under otherwise similar con- ditions the richest m fatty acid of molecular weight; the fat globules of the brS of the lowlands are smaller than the fat globules of the cattle from the highlands Babcock ThZZ^fJ''''\"f\'^''T''\''''' P^^^"'^^ '^'^'^ ^^^ ™«r« imfforrLt globules than the Holstemswhile_ Ayrshires have small, irregular fat globules in their milk Milk with large fat globules is preferable for butter making, since these produce butter of good consistence and good taste with a low melting point. proauce outter ot The ash content of milk from highly bred animals is some- times somewhat lower in CaO and P.O. than that of the common breeds but the fluctuation is such that definite deductions cannot be established In highly improved breeds Pages found: CaO in 143 to 0.227% and RO. in 0.18 to 0.273%; in common breeds the same elements amount to 0.15 to 0.204, and 153 to '^96 respectively. '" ' These characteristics of breeds are general, but they are not so constant that individual strains, individual families, and espe- cially particular animals may not present exceptions. This fact iSiduS br^'V ^^^^^"^^ ^^^ increased milk production within mother was 3 08 tn 3 77% ^!t,'^ T^^ f"™^!" ^^ '""'^^ ^^ ^^^'^ the fat content of the Sly-- but i soon as th^: Sf ^^ r?'°* "^ ^^' ""''^^ «^ ^^^ ^^"g^*^^ ^^^-^^^^^^ "^^t^" no longer sufficW ?o 5 ff '-^'^^^ or exceeded 3.77%, the influence of the bull was maiS lower than i^f^rT/''''?r^t *^' Percentage of fat, and the percentage re- tTer'l Lid down by Galt^n f" ^"^'^ experiences of Hogstrom's were^onfirmld by 54 Internal Innnenccs on the ("liaraeter of Milk. The great variation wliieli occurs in the milk production of individuals of the same breeds depends on hereditary qualities. According- to the statistics of the dairj^ control station at Algau, animals of the Algauer breed produce : Quantity of Fat Percentage Quantity of Milk ■ Fat Maximal production 5201 kg. . 4.(i03 181.93 kg. Minhnal production 1255 kg. 2.493 45.31 kg. Difference 3946 kg. 2.11 136.62 kg. Among 50 of the Jeverland breed Maximal production 8699 kg. 3.713 286.76 kg. Minimal production 2449 kg. 2.482 75.21kg. Dilference 6250 kg. 1.231 211.55 kg. The production of single individuals during the lactation period is sometimes remarkably large. Some of the folloAving data relative to production is taken from Kirchner's handbook. Pei'centage Quantity Author Cow Quantity of Milk of Fat of Fat Kirsten Wesermarsch .. 11291 kg. 2.78 , 324 kg. 5th calving Kirsten East Friesian . . 9047.75 kg. 3.07 277.77 kg 6th calving &• "•"' -11.11 XVj^. Woll Guernsey 6768 kg. 5.745 388:8 kg. ''Yeksa Sunbeam" Kirchner also quoted a case in which a farmer observed that a seven-year old cow in the second month after calving still pro- duced 50 liters of milk per day. Just as the quantity of milk and percentage of fat may vary, so also the fat-free solid substances may vary in the individuals, although only mthin narrow limits. The rule also holds good here that an individual with milk rich in fat will at the same time pro- duce more fat-free solids. Normally fed animals which are not individually large pro- ducers cannot be brought up to a remarkable increase of produc- tion through any agency. The elimination of the poor assimilators of food in favor of good producers, which is a matter of economic necessity, should be based upon the capacity of the individual cow to properly utilize her food. Only through a systematic test of milkings and production records can the profits of the dairy be increased. In judging individuals as milk producers by their external conformation, the following rules of the German Society for Breeds and Breeding may serve as a basis : Influence of Age. 65 (a) Heavy milk production is usually associated: 1. With low body weight, 2. With low measurement at the shoulder, 3. With a straight back, although slight deviations should not be considered as signs of small milk productiveness. 4. With more or less prominent hips and rump according to the characteristics of the breed. 5. With the more pronounced depth of thorax ; heavy milkers are often narrow and flat chested ; 6. With long shoulders, 7. With long rumps, 8. With long, narrow head, 9. Generally with fineness of horn, 10. With fine bony structure ; 11. The most important is the udder. The best cows have large udders of spongy-granular consistence, with large tortuous mammary veins, large milk wells, and easily movable skin. The skin should lay together over the perineal surface of the udder in 4 to 6 or more large, well developed folds. The udder should collapse thoroughly after milking, and the animals should be easy milkers. Relatively early calving seems to have a good in- fluence. The possibility of estimating the qualitative production of milk from external conformations is only very slight. As a rule, as shown by investigations, the smaller and shorter animals with fine long bones produce milk of higher quantity, and above all milk with a large yield of fat. The productiveness of one and the same individual varies, especially with age and the lactation period. Cows with the first calf, provided normal conditions prevail, do not produce as much milk as after subsequent calvings; as a rule when cows reach the age of 7 to 9 years with the fifth and sixth calf, the maximum pro- duction is obtained. With the advance of age the production again gradually recedes. The proportion of solids is higher in cows with the first calf than in those which have calved several times; the quantity of fat on the other hand, as compared with that of older cows, is smaller (Teichert, Hittcher, Hogstrom, Vieth and others). The variations which are manifested in the production of milk during single lactation periods are considerable, and depend en- tirely upon the individual, as does the length of the milking period. For a few days after parturition a product is secreted which has very little in common with milk, and which may be considered as a product of glandular inflammation as a result of physiological irritation. It corresponds strikingly in its appearance and com- position, as well as in the microscopical appearance of its cream and sediment with the inflammatory product of the milk gland. This product called colosirum is a yellowish or even yellowish-red, slimy fluid, with an acid reaction. Corresponding to the increased content of albumen, globulin and 6(3 Internal Influences on the Character of Milk. fat in colostrum, as compared "n-ith ripe milk, the amount of dry substances in eolos- tral milk is very high, and its si)ecific gravity is increased. Tiie amount of urea, cre- atinin, cholesterin, and lecithin in colostrum is increased. The milk at this stage is rich in fat-containing glandular epithelium in the form of foam cells, and seal-ring- shaped cells with so-called caps and moons, and in allniminophores. Numerous leuco- cytes are to be found, and during the first days red blood corpuscles are also present in great numbers. According to Emmerling, cow colostrum, on the ?norning after the birth of the calf, consists of 76.14% of water, and 23.86% of dry substance, of which 4.705% is casein, 0.58 albumen, 8.320 globulin. Compared with normal milk, the fat content is increased or diminished, the milk sugar diminished, and the ash contents increased. Engling found the following values for colostrum : Immediately after After 10 After 24 After 48 After 72 calving hours hours hours hours Specific gravity 1.068 1.046 1.043 1.042 1.035 Solids 26.83 21.23 19.37 14.19 13.36 Casein 2.65 4.28 4.5 3.25 3.33 Albumin and globulin 16.56 9.32 6.25 2.31 1.03 Fat 3.53 4.66 4.75 4.21 4.8 Milk sugar 3.0 1.42 2.85 3.46 4.1 Ash 1.18 1.55 1.02 0.96 0.82 The composition of the ash differs from that of ripe milk, as may be observed from the findings of Sehrodt and Hansen : Eipe Milk (10 days Colostrum after calving) KoO 17.4 24.12 NaoO 10.10 8.72 CaO 22.99 22.69 MgO 6.88 2.92 FeoOs 0.42 Traces SO3 2.82 4.10 P9O5 34.30 30.73 ^ "Cl 6.85 8.30 The ferments in colostrum also deserve special consideration. The amylase content is considerably increased, also the amount of catalase. During the colostral period the milk further con- tains hemolytic amboceptors and increased complement. Formalin methylene blue is not decolorized. The reaction of the colostrum is acid. The colostral period lasts from 3 to 5 days after calving. In heifers the transition period results more slowly than in old cows (Deisman, Hittcher). Up to the end of this period there is a constantly increasing approach to the properties of ripe milk^ together with an increase in the yield, which continues to increase until the first or second month, and then gradually recedes and finally rapidly diminishes towards the end of the lactation period. The reduction of the milk yield corresponds with an increase in the percentage of fat. The fat globules become smaller and more numerous. At the end of the lactation period the milk again assumes the character of colostrum, becoming especially rich in chlorine, and sodium oxide, while the phosphoric acid and the potassium contents appear diminished. The milk becomes salty, bitter, and its reaction alkaline. The entire time of lactation or one lactation period, usually lies between the birth of two calves^ Influence of Disease. 67 and is divided into the lactation period and the dry period. Good milk cows give milk on an average for 300 days. Cows which are not bred again, or which cannot be impregnated, may have a con- siderably longer lactation period. During estrum a considerable diminution of milk in quantity and quality may be observed in cows. Sucking calves may at this time become affected with digestive disturbances. Hittcher and Neumann state that the quantity and the proportion of fat dimin- ish, while the casein contents and the specific gravity of the milk are increased. There are however no set influences in one and the same animal, and still less so in different individuals. Sometimes the quantity of milk even increases, and not infrequently the milk becomes abnormally rich in fat (Martiny). Fascetti and Bertozzi found diminished quantity, increased specific gravity, and in- creased dry substance, which they supposed resulted from the in- creased proteid contents, especially from the increase of fat. The volatile fatty acids in the fat according to Nilsen are diminished, and the degree of acidity of the milk is frequently increased (Mez- ger). As a whole, however, the milk is not materially changed (Weber). No observations have been made on the influence of coition and the beginning of another pregnancy. However the milk of cows far advanced in pregnancy frequently has a lower value. It coagulates sometimes as early as in the sixth, seventh, or eighth month of the gestation period. Finally it becomes slimy, yellow, and shortly before the cow goes dry it shows a similarity to colos- trum. The amount of phosphoric acid and lime, contrary to that in colostrum immediately after calving, is diminished, and the taste is bitter and rancid (Backhaus). If cows are spayed 5 to 6 weeks after calving the milk is supposed to be richer in fat, casein, and ash. The lactation period of such cows is considerably lengthened, according to Grouin ex- tending to 6 years. Lajoux on the other hand states that in healthy animals the quality of the milk remains the same, but during the course of lactation the cows do not dry off so rapidly and the yield is therefore greater. Milk which is produced after abortion is supposed to be sim- ilar to that of ripe milk (Schaffer and Hess). The lactation period however is short, and the milk yield small. If the cow remains farrow for a long time a greater yield is obtained. This however is only slight, and does not compensate for the shrinkage during the latter part of the milking period. Influence of Diseases. Relatively little is known of the chemical changes which milk undergoes from the influence of general affections of ani- mals. We are in possession of better information relative to the 58 Internal Influences on the I'liaraoter of I\Iilk. occurrence of specific disease agents in milk, and it is known that these pass into the milk either directly from the blood being then eliminated with the milk, or else they reach the milk through sub- sequent contamination of the milk with excretions. A rapid diminution of the milk yield is characteristic in all acute diseases associated with great pain and fever, and in some cases a sudden cessation of the secretion may be observed. Whenever the yield of milk of a cow suddenly shows a con- siderable diminution, all of her milk should be excluded from mar- ket, even though the animal shows no visible affection and before the disease can be recognized as a general or specific affection. In the sense of the pure food law the milk of every severely affected cow should be considered unfit for food without any further con- sideration. Sometimes this unfitness of the milk is numifestod by strong objective perceptible changes, as compared with the secretion of healthy animals. The milk may become bitter, salty, have an increase of ash and albumin, and coagTilate more rapidly than healthy milk (Jensen). The fat content of the milk is at the same time diminished or in- creased, while the sugar and ash contents may show fluctuation. The amount of catalase present, according to Spindler, may in- crease considerably, especially in cases of peritonitis and tubercu- losis. The reaction of the milk remains acid or becomes slightly alkaline. According to Schnorf, most of the internal affections, even when the udder is not involved, produce a diminution of sugar and proteid contents as a result of increased metabolism. The electrical conductivity of the milk of animals with general affections is subject to great fluctuations. After tuberculin injec- tions with subsequent fever, the milk shows a slight increase in its electrical conductivity. The index of refraction in pathological milk is normal, and not diminished ; the temperature at which freezing occurs is not infrequently higher. During the course of individual diseases the following should be considered: An elimination of toxins and toxic products of metabolism with the milk is to be feared in all septic and pyemic diseases. If with this there is a possibility of contamination with pathological excretions, as for instance in septic metritis, hemorrhagic or ichorous enteritis, or in the retention of putrid afterbirth, the milk should be considered harmful. In septic metritis the infective agents pass from the uterus into the meat and into the udder, from which they may be eliminated. Basenau demonstrated the Bacillus morlnficans hovis, a meat poisoning organism of the colon typhoid group, in the meat during the existence of septic metritis. The stapylococci and streptococci which are frequent participants^ in mixed infections of the uterus, are also eliminated with the milk, provided the udder has not already ceased its secretion. Influence of Disease. 69 Milk from cows affected with acute and sub-acute intestinal inflammations should be judged in the same way as milk from animals affected with septic metritis. The ingestion of milk from cows affected with bloody or fetid diarrheas should be especially guarded against. The appearance of sickness in man after the ingestion of such milk has been satis- factorily proved by Gaffky and Follenius. Two assistants and a helper of the Hygienic Institute of Giessen drank milk of this character and became sick with dullness, headaches and chills. After two days diarrhea, vomiting and high fever appeared. The clinical manifestations in the two assistants simulated those of typhoid fever, while in the helper they were similar to those of Asiatic cholera. The milk originated from a cow affected with hemorrhagic enteritis. Gaffky demonstrated rapidly growing and strongly virulent colon bacilli both in the bloody excrements of the cow and in the stools of the affected patients. In the presence of infectious diseases the milk of the en- tire stable should be withdrawn from use, or should be rendered safe by suitable treatment, as for instance by pasteurization. Such milk should never be sold as certified or infants' milk. Jensen ex- tends this prohibition even to milk from stables in which white scour of calves, and other calf affections of an infectious nature have occurred. Dangerous properties of the milk should also be considered in the appearance of other diseases, as for instance malignant catarrh- al fever, purulent broncho-pneumonia, traumatic pericarditis, rin- derpest, etc. (Bongert). In all cases of hemorrhagic, purulent, acute or chronic inflammations of the kidneys the milk should be judged similarly to milk from animals with intestinal inflamma- tions. In such affections the freezing point of the milk approaches zero, and the refraction index is lower. At the same time these values in animals affected with inflammations of the kidneys vary extensively. Special Infectious Diseases. Tuberculosis of animals, especially its hygienic importance, is considered here in connection with tuberculosis of the udder. It should be mentioned at this point that some investigators be- lieve that the toxins of the tubercle bacillus pass into the milk. A change of the quality of the milk will occur only in cases in which the advanced chronic affection of the animal results in lasting emaciation, or when an acute attack of the disease, associated with fever, appears during the chronic course of the disease. In tuber- culosis the milk may become bluish, and poor in fat, the sugar and proteid substances may be diminished, or the latter may be even in- creased (Storch). Several tables, which indicate the experimental results of Monvoisin, are taken from Grimmer 's ''Chemistry and Physiology of Milk." "Q Tnternal Influcnoes on the CliaracttT of Milk. 1000 gm. of milk coiitainod Tube.vuiou. o..ws Avitiiout Healthy cows tuhorculosis of the udder. Acidit V as lactic acid 1 . 543 . OG-t 1 . 292 Totarnitrogeii 5.87 8.67 4.21 Fat 46.5 29.6 59.7 Sugar 43.5 29.8 43.9 Solids 142.3 126.05 147.5 Ash 7.3 8.2 6.7 Clilorin (sodium chloride) ... 1.4 4.13 1.05 Freezing Point — .55 — — Eef raction at 15 deg 1 . 3434 1 . 3416 1 . 3442 In rinderpest;, according to Busson, the amount of fat and sugar diminished rapidly, whereas the casein, albumin and salt increased. The passage of the contagion of rinderpest into the milk in a direct way from the blood is j^robable; the milk, how- ever, can be contaminated with certainty through infectious secre- tions and excretions. Rinderpest is of no practical importance from the standpoint of milk hygiene, to most of the European countries (with the exception of Turkey), since it has been eradi- cated with the aid of veterinary police measures and even in the event of any possible introduction, it Avill be immediately sup- pressed. Milk from cows affected with contagious pleuro-pneumonia is supposed to have caused the death of children (Randou, Lecujer and Wiedemann). Secretion of milk is immediately reduced at the onset of this disease, it becomes poor in fat and sugar, richer in albumin and ash, its appearance resembles that of colostrum, and its taste is peculiar. The contagion of pleuro-pneumonia appears to pass into the blood but rarely, and therefore its elimination in the milk can occur only exceptionally, if at all. Contagious pleuro- pneumonia is also subject to the most stringent veterinary police measures, and therefore has but little practical imjoortance for milk hygiene. Similar conditions prevail with pox of cattle. This disease however demands our interest for the reason that the infectious agent of cow pox must be considered as a mild form of smallpox of man. Cattle usually become affected through transmission of the disease from naturally infected men, or from those vaccinated with cow pox. The infection occurs if during milking the contagion of pox is rubbed into visible or invisil^le wounds of the skin of the udder. The infected teats manifest roundish or oval, hard papules of the size of a pea, which after 1 to 2 days change into yellowish- Avhite vesicles of a mother-of-pearl luster. After ripening into pns- tules which requires from 8 to 10 days, the lesions show a charac- teristic depression in their center, the so-called navel of the pox. They either rupture and suppnrate, or dry and heal, leaving a superficial scar. The udder becomes sensitive to pain, the milk is thinner, and Influence of Disease. 71 of lower specific gravity, but richer in albumin (Jensen). The injection of the contagion of pox into the ducts of the udder results in the development of pox vesicles on the walls of the milk ducts. After 2 to 3 days a swelling of the udder, with increased sensitive- ness, develops and the secretion is changed. It becomes purulent and bloody on the eighth to the tenth day (Lienaux and Hebrant). Transmission from animal to animal may be brought about by milking, and the entire herd in a stable may rapidly become af- fected. The course of cow pox is usually benign. According to Herz the milk becomes rich in cells, contains colostral bodies, and it has an unpleasant taste. Careful examination showed the fol- lowing results : Beginning of After 13 After 40 observations days days Specific gravity of the milk 1 . 0265 1 . 0270 1.0215 Specific gravity of the whey 1 . 0245 1 . 0235 1 . 0209 Acidity according to Soxlilet-Henkel . 5.3 6.6 4.1 Fat 5.36% 4.02% 5.54% Solids 13.31 11.82 12.25 Fat-free solids 7.95 8.81 6.72 Ash 0.72 0.72 0.8 Transmission of pox from cattle to man is of course very readily possible, and is not at all uncommon as a result of milking affected animals. After the ingestion of infected raw milk the pox exanthema may develop on the face (Jensen). The so-called false or gangrenous variola which may be fre- quently observed on the teats of fine-skinned, fresh milking animals should not be mistaken for true pox. These eruptions are pro- duced by the ordinary pus-producing organisms, which have been rubbed into the skin during milking or have penetrated the skin by means of various injuries. Small furuncles and skin abscesses result, which heal without influencing the formation or secretion of the milk. Healing is of course retarded through the act of milk- ing, and during the presence of the pus cells, blood and pyogenic organisms may pass into the liiilk in small quantities. These false pox lesions are not very important. Of much greater importance than cow pox is foot-and-mouth disease which sometimes appears extensively. This is a highly acute febrile disease which is transmitted to cloven-footed animals with remarkable ease. The most striking symptom which occurs in association Avith the disease, the vesicular eruptions, may also affect the udder, and especially the teats. The udder swells, becomes painful, and red-bordered vesicles develop in sizes up to that of a walnut, which burst during milking or spontaneously, leaving painful ulcers. During the beginning of foot-and-mouth disease the yield of milk is considerably dimin- ished, sometimes one-quarter less than the usual yield, as a result 72 Ttitcnial Influences on the Character of Milk. of tlie febrile affection and on account of the inappetence due to the pain caused by the vesicles in the mouth and on the feet. The effect of the disease upon milk secretion varies according to the individuals, the age and the lactation. Siedamgrotzla-^, Weber and Born have published the effects of the disease on milk secre- tion during outbreaks in certain herds. In 43 cows the quantity of milk at the height of the disease dropped from 745 to 364 liters, and again rose after the eradication of the outbreak to 522 liters. Thirty cows of another herd gave only 30 liters instead of 300 liters of milk during a period of eight days. In a third herd the quantity of milk dropped from 510 to 260 liters, later rising to only 350 liters. Other figures showed a decrease from 750 to 280 liters, with a subsequent rise to 400. The diminished yield per cow per day Avas from 5 to 6 liters and even more. In cows that have been milking for a long time the loss in milk reaches as high as 75%, in animals in the middle of the lactation period up to 43%, while in fresh milkers it may amount to 55% (Hutyra and Marek). Sugar and fat contents diminish, but at times the amount of fat may become considerably higher. The volatile fatty acids are diminished, but the milk contains more albumin and salts, an in- creased amount of throAvn-off epithelium, colostral cells, pus cells, and also red blood corpuscles (Lavena, Kalantar, Herberger, Kreis, Vogler and others). The catalase content is increased even if the udder manifests no changes (Bertin-Sans and Gaujoux). Honigiiiund examined five cows affected with foot-and-mouth disease, one of which was not visibly affected on the day of the examination although already infected. The individual data in- side of nine davs were as follows : Quantity Tempera- Specific Fat Con- Nitrogen- of INIilk ture Gravity tents ous Subs. Sugar Solids Ash 15 L. 38.7 1.032 3.05 2.99 4.24 11.62 0.74 6—7 39.6 1.031 5.4 2.97 3.63 13.00 0.63 6—7 38.9 1.030 4.3 2.99 3.80 12.81 0.89 about 8 39.0 1.030 3.43 3.04 3.91 11.33 0.65 8 — 10 38.6 1.031 3.06 3.04 4.15 11.01 0.70 8 — 10 38.4 1.029 2.9 3.1 4.49 12.03 0.69 about 10 38.6 1.030 2.84 3.19 4.57 11.21 0.71 10 — 11 38.5 1.032 3.45 3.24 4.41 11.77 0.67 about 12 38.4 1.031 3.25 3.33 4.38 12.30 0.70 It appears also from the other investigations of Honigmund, in which the animals showed s^niiptoms of the disease as early as on the first day of the examination, that the fat and ash content is greater in the first day than in normal conditions. The total solids and also the fat-free solids fluctuate considerably. When catarrh of the milk ducts becomes associated with foot- and-mouth disease, the milk becomes yellowish, of a rancid, bitter taste, colostrum-like, and similar to the secretion during other in- Foot-and-Mouth Disease. 73 flammatory conditions of the udder, that is, slimy, watery and in- termixed with coagulum. ' It is an important fact that milk from animals which are af- fected with foot-and-mouth disease will contain the virus of foot- and-mouth disease, if it has been contaminated by the vesicular contents. Nocard succeeded in proving, however, by careful ster- ile drawing of the milk from cows affected with foot-and-mouth disease, that the milk does not contain the virus of foot-and-mouth disease as it leaves the udder. Nevertheless it is not satisfactorily proved that a direct elimination of the virus may not take place at the beginning of the febrile state, as at this time the virus is present in the blood If the udder itself is affected by the eruptions of foot-and-mouth disease it is hardly possible to avoid contamination of the milk with the vesicular contents. Considering the ease with which the virus of the disease is spread, it may be assumed that the entire milk of a herd affected by the disease, under ordinary conditions of milk production, contains the contagion of foot-and-mouth disease, strict veterinary pohce measures must be inaugurated to prevent the spread of the disease. Sale of the milk should be permitted "^Tl^^. ?y^^^^^* heating. The maintenance of a temperature K,-^^' one-half hour will make the milk perfectlv safe Milk containing the living virus of foot-and-mouth disease must be considered deleterious to human health, since it has been estabhshed by experiments and observations that the disease is transmissible to human beings. Vesicular and ulcerated inflam- matory changes of the buccal mucous membrane with fever and general symptoms develop with possible vesicles and ulcers on the hands, arms, breast, lips, ears, and in the throat. Vomiting and diarrhea may be associated with symptoms of a gastro-intestinal mtlammation, and the affection may even terminate in death (Bus- senius and Siegel, Jensen, annual reports of the Imperial Board ot Health, Hertwig, Stickler, Schreyer, Krajewski, Walkowski, and others). Bongert suggests the separation in dairy stables of the non-altected, slightly and severely affected animals into isolated groups and m order to reduce the economic losses as low as pos- sible the milk of these groups should be treated in different wavs Heated milk from the non-affected animals for instance, could be utilized as infant's milk. The milk from slightly affected animals could be marketed as ordinary milk [after pasteurization], while the milk from the severely affected cows or milk changed in its consistence, should be excluded from consumption even in a heated condition. Even with this separation the losses will necessarilv be high as a result of the enforcement of stringent sanitary regu- lations. .' to According to Ebert sour milk 3 to 4 davs old is no longer capable of transmitting the infection. The transmission is possi- 74 Effect of Internal Influences. ble through cheese and butter (Frohner, Ebstein, Thiele, Schnei- der, Frick, Frohlicli). The general rules which have been indicated above obtain also in changes of the milk in malignant oedema, blackleg, or parturient blackleg of cattle. Transmission of these diseases through the consumption of milk from affected cattle, or through the diseased products of contaminated milk, is not to be feared; besides milk production ceases very rapidly in the affected animals. The same rules should apply in judging milk from animals affected mth hemorrhagic septicemia, a disease which is pro- duced by a bi-polar bacterium. This disease is transmissible to calves, through sucking or feeding milk from affected animals. Anthrax of cattle should also be mentioned. This runs in an acute or sub-acute form, and as a rule is associated with a sudden cessation of the milk secretion, which occurs even as early as at the beginning of the fever. The anthrax bacilli only multiply towards the end of the disease sufficiently to cause a direct passage from the blood into the milk. If the secretion has continued to some extent this direct passage is possible even if no hemorrhages, such as are typical during the course of anthrax, have developed in the parench^ana of the udder. The demonstration of anthrax bacilli in milk has been accomplished microscopically, and by inoculation and cultural experiments, but not in all the cases which have been examined (Bollinger, Chambrellent and Mous- sou, Feser, Monatzkow). In severe cases the milk becomes yellowish, bloody and slimy. At the appearance of the fever the fat and sugar contents are in- creased, while the proteid contents are diminished. The danger of infection through the ingestion of raw milk con- taining bacilli is slight, since the anthrax bacilli are digested by the gastric juice. More dangerous than the bacilli which may pass into the milk from the blood are the anthrax spores which may reach the milk through contamination with manure of affected animals, or through straw and stable dust, since the resistant spores are not destroyed by the gastric digestion. The virus may also be present at times in normally healthy animals after they ingest food containing anthrax spores.. The milk may become infective through contamination with feces from such bacilli car- riers. In spite of the fact that there are remarkably frequent opportunities to obtain milk with bacilli and spores from localities in which anthrax persists epizootically as a disease of the soil, yet only one anthrax infection of man is known to have occurred through the ingestion of milk. This resulted in a patient with typhoid fever, who after drinking li/o liters of milk became affected with intestinal anthrax. The milk was derived from a cow mth a malignant pustule on the udder, which had died in the meantime from anthrax. Rabies. 75 Lehnert states that the calf of a cow affected with anthrax re- mains well, although it may suck the mother through the entire course of the disease. Even though milk offers a splendid nutritive medium for the anthrax bacillus, an increase of bacilli only occurs during the first three hours. Keeping the milk at room temperature for 18 to 24 hours, is followed by the death of the bacilli (Caro). At the beginning of souring the vegetative forms of the virus are quickly destroyed; the spores however remain active (Inghilleri). If anthrax bacilli are cultivated in milk, coagulation occurs under the rennet action of the peptonizing bacterial ferments. The coagulum again slowly dissolves, and the milk separates into fat and whey. Less important than anthrax is rabies, as this disease occurs much more rarely in cows. According to Nocard and Bardach the milk of animals affected with rabies contains the virus. Never- theless the danger to man from the ingestion of such milk is hardly probable, since it is impossible to affect experiment animals by feeding fresh milk (exceptions are rats and mice). A nursing infant of a woman affected with rabies remained well, although it was fed with the milk of the patient until one day before her death (Bardach). The uninjured mucous membrane of the mouth, pharynx, and the intestinal tract does not offer opportunity for infection. This opportunity is afforded only when destruction of tissue and small wounds permit the entrance of the contagion. Thus for instance Galtier succeeded in producing rabies through rubbing brain material of rabid animals into the mucous mem- brane of rabbits. According to the observations of Virschikowsky the rabid virus is destroyed by the gastric juice. Very little, or nothing at all is known relative to the special relationship of other infectious diseases to milk, as for instance malignant catarrhal fever, croup of cattle, the blood diseases of cattle caused by spirochsetes, trypanosomes and piroplasma, or in- fectious vaginal catarrh and infectious abortion. In the presence of infectious vaginal catarrh and contagious abortion the milk secretion is supposed to be diminished. It should be remembered that in such affections the passing of the disease agents from the blood into the milk is possible. [That the bacillus of infectious abortion is eliminated by the milk has been definitely established. See Bureau of Animal Industry Circular No. 216]'. In a case of icterus in a woman Mayer observed the passage of bile acids, especially taurocholic acid into her milk. Finally two other diseases should be mentioned which ma3^ be transmitted from animal to man : 1. Milk Sickness. A rather peculiar disease, called ''milk sickness," is found in the central part of the United States, where it at times occurs as an epidemic among cattle and people. In cattle, the first indication of disease is dullness, followed by violent Effect of Internal IiiHiii'nces. trembling and great weakness, wliieli increases during the suc- ceeding day until the animal becomes paralyzed and dies. Through the ingestion of flesh, milk, or dairy products of an alfected animal the disease is transmitted to man or to another animal, and at- tacks produced in this way most frequently prove fatal. In man the disease develops with marked weariness, vomiting, retching, and insatiable thirst. Respirations become labored, peristalsis ceases, the temperature is subnormal, and the patient becomes apathetic. Paralysis gradually follows and death takes place quietly without rigor mortis. Many efforts have been made to elucidate the question re- garding the nature and cause of this disease, but although many theories have been discussed none of them has so far been general- ly accepted. Some investigators hold that the disease is of micro- organismal origin, some that it is due to auto-intoxication, while others think it is caused by vegetable or mineral poisons All seem to agree, however, that the disease is limited to low, swampy, uncultivated land, and that the area of the places where it occurs is often restricted to one or a few acres. Furthermore, when such land or pastures have been cultivated and drained the disease dis- appears completely. The discovery of a new focns of this disease in the Pecos Val- ley of New Mexico in November, 1907, gave Jordan and Harris the opportunity of studying this peculiar affection by modern bacter- iological methods. As a result they have succeeded in isolating in pure cultures from the blood and organs of animals dead of this disease a spore-forming bacillus which they name '' Bacillus lactimorhi." With this bacillus they have reproduced in experi- ment animals the symptoms and lesions peculiar to milk sickness or treml^les, and from these animals the same organism has been recovered in purit}^ It therefore appears to have been demon- strated that the bacillus in question is the probable cause of the disease. As Jordan and Harris have already indicated, more com- prehensive studies, based on a larger supply of material, are desirable in order that the many obscure and mystifying features connected with the etiology of this rapidly disappearing disease may be elucidated. From the above facts it seems evident that milk sickness is an infectious disease communicable to man, and the cattle owners should therefore not be permitted to make use of the meat or milk of affected animals for human consumption. Trans.] 2. Malta Fever. On the coast of the Mediterranean, in South Africa, India, China, Philippines, America, and especially on the Island of Malta, there occurs in goats a disease which exists in the animals without producing any or at most only very slight sjnuptoms. Cows may also possibly be affected. The infected animals eliminate for months, frequently at intermittent periods, the virus of the disease (Micrococcus melitensis , Bruce). Follow- Mastitis. 77 ing the ingestion of such milk ' ' Malta Fever ' ' develops in man. It has a protracted course with recurrences, and is accompanied by anemia, headaches, rheumatic pains, constipation and swelling of the joints. Malta fever terminates fatally in about 3% of the cases. The goats show on postmortem, swelling of the spleen and lymph glands, frequently also inflammations of the kidneys and lobular pneumonia. The virus is relatively resistant against souring of the milk, but at 70 deg. C. it dies in 10 minutes. According to Zammit about 10% of all the goats on the Island of Malta eliminate the virus, while 50% of the animals show by the agglutination test that they are or have been under the influ- ence of the Micrococcus melitensis. We are in possession of better information concerning the changes which milk undergoes in inflammations of the udder than we have regarding the effect on the milk secretion as a result of general diseases, or regarding the importance of milk from affected animals from a hygienic standpoint. Changes in Appearance, Consistence, Contents, Etc., During- an Attack of Mastitis. Relatively very little is known as to the influence of the dis- eases ot the udder on the chemical and physical character of the milk, although it is well known that with the changes in function and condition of the organ the product is also changed, as com- pared with the product of the normal gland. Even in the same disease the product varies in accordance with the intensity dura- tion and the extension of the disease, the same as it naturallv varies m accordance with the nature of the injury to which the parenchyma is subjected. As a result of these conditions the re- sults o± the data of different authors vary considerably It may be said in general that in affections of the udder the projDortion of the proteids, sugar, salt, fat, and enzvmes in the milk becomes altered and that the relation of the individual pro- teids, the salts and the enzymes, also undergoes fluctuations. In acute and greatly extended chronic inflammations, both fluid and cellular constituents of the blood may pass into the milk, cells of the parenchyma are thrown off, coagulation sets in, and brieflv, the milk changes more or less rapidly in appearance, taste and contents, so that it deviates considerablv from the milk of healthv cows. ' ^ ^J At times none of these characteristics appears, especially in the early stages of chronic inflammations of the udder, or after the subsidence of the acute symptoms, and it is then onlv possible with tlie aid of certain methods of examination to differentiate such altected milk from normal. Therefore of special importance to milk hygiene are the chronic inflammations, and inflammatory stages in which the 78 Effect of Internal Influences. clianges of the secretion appear slowly, and relatively late, while inflammations of an acute character very quickly produce a tre- mendous change in the secretion, the mixing of which with market milk would be the grossest negligence. It is to be regretted that such cases occur. Appearance of affected milk : In forms of inflammation which are associated with rapid development, painful swelling and in- creasetl temperature of the udder, the milk nsually has a bloody discoloration, later becoming yellow (colostrum-like), and finally changes into a custard, or honey-like secretion, in which thick, yellow and yellowish-brown flakes are suspended in a more or less clear serum or plasma. Such changes are observed in samples of milk in acute forms of mastitis, through infection of bacteria of the colon group, in mixed infections, in acute attacks or in great extension of strep- tococcic mastitis, and in infections with the Bacillus pyogenes, etc. In chronic affections the milk clianges only slightly or not at all during the beg-inning of the disease, or it may appear normal long before the disease as such is considered cured. If such nor- mal appearing milk from affected quarters is allowed to stand for several hours a white, yellowish-white or yellowish sediment settles to the bottom. At the same time the quantity of cream is increased and changed, appearing yellowish, tenacious, and when shaken it assumes a cloudy or wavy appearance. If the migration of the pns corpuscles from the blood vessels becomes more inten- sive the milk appears thick, ^'-ellowish, cream-like, and after stand- ing separates into a yellowish-white to ocher colored sediment, which may amount to two-thirds or more of the entire mass, and into a dark, transparent, yellowish-grey to greenish-yellow skim milk. The sediment layer is at times increased, at other times decreased. The cream becomes granular, shredded, and tenacions. If red blood corpnscles are eliminated in great numbers they col- lect in the form of a red disc on the yellow to yellowish-brown base, which is composed of leucocytes and coagulation masses. In hemorrhagic stages of the inflammation the milk is pinkish or brownish-red; by sedimentation it separates into a Bordeanx-red or rust-colored precipitate, and a pinkish-red layer of cream over the reddish-gray skim milk. In other cases the milk becomes grayish and watery, and only a few thin conglomerates and fat globules indicate the layer of cream. Cream and sediment are especially rich in cells in all forms of inflammation. Epithelial cells are desquamated into such milk in the form of colostral cells, or entire epithelial bands, and numer- ous polynuclear leucocytes, besides single epithelial cells, into which macrocytes penetrate (albuminophores), erythrocytes, cell debris, fragments of nuclei, as well as Nissen's globules are found. Besides concrements of the most varied quality, casein and Mastitis. 79 fibrinous flakes appear (Zscliokke, de Bruin, Kitt, Sven Wall, Doane, Russell and Hoffman, Rulnn, Ernst, Balir and others). The taste of milk from affected quarters of the udder is also affected markedly, the milk becoming salty, bitter, and pungent. According to Craandijk in 67% of cases the taste of the milk changes in streptococcic mastitis. From the appearance which the affected quarter manifests, as compared with healthy quarters, from the change in the behav- iour of the animal, from the varying quantity of the secretion against the quantity from healthy quarters or the previous yield of the same quarter, the milker becomes suspicious of the existence of an abnormal condition in the suspected quarter, and the tasting test reveals a salty, bitter taste which assures him of the appear- ance of a change in the activity of the gland. If the udder secre- tion could be examined on the hollow of the hand before being milked into the pail, in order to determine the possible presence of flakes, etc., as should be the duty of the milkers, then the mix- ing of such mill! from affected quarters would not occur to the extent that it does at present, as has been proved on numerous occasions. A great deal would be gained if the milk from those quarters which produce a milk so changed that its abnormalities can be recognized by its appearance or taste could be totally de- stroyed. As a matter of fact milkers can much more readily rec- ognize developing inflammations of the udder (as for instance streptococcic mastitis) from the varying conditions of the udder, or quarter, the quantity of milk, and the behavior of the animal, than the veterinarian can by a single clinical examination. Therefore the method applied in practice consisting of a single clinical examina- tion of the cows producing infant milk at the time of purchase, or every 3 to 4 weeks is not sufficient to determine the presence of ud- der affections. Periodical examinations of all cows producing certi- fied milk, supplemented by tests of the milk obtained at the time of the examination, are necessary when the inspection is to serve its purpose. At the examination in the stable a comprehensive history should be taken from the milkers relative to the general condition of the cows, their action during milking, the condition of the teats and the gland tissue, the inflammatory changes noted, in fact all points which may offer valuable supplements to physical examina- tion. One may learn from questioning that the cow milks very hard from one quarter, that she sometimes refuses to ''give down'"' her milk, or that she "draws up" the milk or that recently the cow has shown a tendency to kick during milking. At other times one may hear that the parenchyma contains knobs or lumps or that the teats contain beads or warts, or are ''fleshy," the quantity of milk is diminished, the milk is sometimes hot, "heated," or that the cow has the "cold garget" Avithout any inflammatory indications of streptococcic infections. The milk is ropy, the 80 Eii'cft oi: lulenuil iullueiicc- quarter is ''blind," tlie milk contains stringy clots and other tilings. The keeping of milk records and the taking of milk samples at least every four weeks, should be reqnired of all owners of animals which ])rodnce milk for city consnmption and those fur- nishing it to wholesale milk dealers. Together with the visible changes in the milk, changes of the value of the chemical and physical properties occur which have been especially studied by Guillebeau and Hess, Schaffer and Bondzynski, E. Seel, Mezger, Fuchs and Jesser and Mai and Ixothenfusser, These changes in the contents and properties are therefore especially important since frequently values are obtained which suggest adulteration with water. Irreproachable comparative tests of milk obtained directly from the stal)le may indicate however that in the specific cases the investigations M^ere l)eing made Avitli al)nornial milk. According to Schaflfer and Bondzynski 's examinations tlio milk from cows affected with mastitis showed the following values : Water Solids. Fat Pro- Milk Total % % teid Sugar Ash P0O4 CI. In non-infectious garget 92.83 7.17 0.82 4.01 0..53 0.79 7.3.5 35.76 In yellow gait 89.34 10.66 1.99 6.00 1.84 0.83 In parenchymatous mastitis 90.26 9.74 2.16 4.21 1.01 0.97 19.21 27.79 In comparison with healthv milk 87.75 12.25 3.4 3.5 4.6 0.75 20.0 14.0 The milk sugar content was also considerably diminished; the amount of mineral substances on the other hand was increased. Guillebeau and Hess give the following values in milk from cows with affected udders: Duration of the Disease and Origin of the Milk Specific Solids. Fat Nitrog- Milk Ash Gravity enous subst. Sugar 7.45 0.52 6.17 0.85 5.15 0.22 4.26 0. 0.82 9.80 1.95 2.98 4.06 0.81 1.0314 11.28 2.72 3.50 4.35 0.70 7.69 1.09 5.74 0. 0.87 23.58 9.30 8.53 4.68 1.07 1.5.88 4.50 5.37 5.14 0.87 9.66 2.09 0.53 6.74 5.13 2.09 0.85 1.5.88 4.50 5.37 5.14 0.87 1.0430 20.94 0.97 16.65 2.61 0.71 1.0379 18.18 2.80 7.93 2.04 0.91 11/2 clays 2 (i 5 " udder recovering 7 " 2 " 2 " 11/^ ' ' from two affected quarters ly. " from two affected quarters 1 " 8 ' ' from two affected quarters 2 ' ' from two affected quarters 21 " In most ca.=es the specific gravity is lower (Seel, Mezger, Fuchs and Jesser) and approaches the normal only towards the end of the disease. In mixed milk from all four quarters the specific gravity is less influenced. The quantity of fat, according to Seel, and in some cases of Mezger, Fuchs and Jesser, is very much reduced. The latter authors emphasize the fluctuation of the fat in sudden jumps. The experience of the official milk control station in Munich also gives similar results, at the beginning of the affection frequently finding abnormally high or again abnormally low fat contents of the milk. Mastitis. 81 The amount of milk sugar as a rule is reduced, and rises only with the appearance or recovery. ^ ^ The solids are likewise usually diminished ; the fat-free substance is also, and only becomes increased after signs of recovery have been noticed. The amount of proteid coagulable by heat frequently increases enormously, as compared with the contents of casein which diminishes. The ash content on the average is increased. Eelative to the composition of theash the data appear to be contradictory. Although Seel found in 15 cases out of 18 a diminution of chlorides against an increased quantity of P2O5 Mezger, Fuchs and Jesser observed an increase of the chlorine content and a diminution of the phosphoric acid, while Steinegger and Allemann found that the amount of P0O5, CaO, K9O and Mo-Q diminishes, m general, while the quantity of CI., NooO and SO3 increases. According to Hashimoto the ash of abnormal milk closely approaches the ash of blood serum (0.78%), consisting of 8.9863 K2O; 36.544 NasO; 7.44 CaO: 1.738 MgO: 17.380 PoO. and 33.627% CI. ^ The reaction of affected milk is mostly alkaline (Seel, Mezger, Fuchs and Jesser, Hoyberg, Auzinger, Ernst), or more rarely acid (Zschokke, Henkel, Wyssmann and Peter, Ernst). The determination of acidity is recommended by Plant as a means for the diagnosis of udder affections. Independently from the degree of acidity, the coagulability on the addition of alcohol is frequently considerably increased but not always, and in some cases not con- stantly. (Henkel, Eullinann and Trommsdorff, Auzinger). The refractability of the calcium chloride serum not infrequently suffers con- siderable changes upward and downward. Eipper, Ertel, Mairhofer, Schnorf, Mai and Eothenfusster, Henkel, Mezger, Fuchs and Jesser found considerable changes in this respect and proved that the daily variations in the refraction may be very great in milk of individual quarters, and even in the full milk of an animal. Frequently however the refraction of the calcium chloride serurn shows no change when compared with the milk of healthy animals. The same variation obtains in the lowering of the freezing point of milk from affected quarters; the values may be considerably higher than that of healthy milk, or on the other hand they may be lower. More frequently a high value is observed (Schorf, Quiraud and Laserre, Crispo, Bertozzi, Pins). According to Schnorf the elec- trical conductivity is always increased, never normal or lower. According to Bonnema the increase of chlorides results in an increase of the electrical conductivity. A change in the contents of original ferments appears very early during the affection, together with an increase of cellular elements, especially leucocytes (Zschokke, Bergey, Trommsdorff and Rullmann), and fibrinous flakes (Doane, Eussell and Hoffmann). According to Koning the increase of the catalase content in freshly obtained milk is an indication of the affection of the ud- der, provided the colostral period has passed. The publications of Spindlers and Rullmann (who were enabled to obtain asepti- cally milked samples with which to work) and the author's obser- vations confirm Koning 's findings. The author observed that in slight, local affections of a chronic nature, without febrile mani- festations, the content of catalase usually runs parallel with the cell content, and it rises when there is an especiallv marked throwino- off of epithelia (presence of typical colostral cells). * The faculty of splitting up added starch solution likewise in- creases m milk from affected udders as compared with that from healthy udders. There are no observations relative to the quanti- tative effects of peroxydase. According to Weichel the peroxy- dase content of affected milk from an artlfically affected goat dis- appeared, whereas the healthy milk gave the guaiac reaction ^2 Effect ul internal Intlueuces. The reaction again appeared when the secretion became of a milk- like consistency. Al'lected milk behaves in various ways on the application of f ormalin-methylene blue solution ; frequently a very rapid decol- oration of JSchardinger's reagent may be observed (Rulimann, Sas- scnhagen, Eievel). iSometimes in typically changed samples the reduction does not take place (author's observation). As the above-mentioned enzymes (not amylase), at least in part may appear to be brought on by bacterial action, their abnor- mal presence in milk has a diagnostic importance only in freshly milked samples. The case is different wdtli the complement con- tent. As indicated in the chapter on antigens, blood constituents pass directly into the milk during periods of physiological and pathological irritations. Therefore in mastitis, as proved bv Bauer and Sassenhagen, complements are demonstrable in the milk. This, according to Sassenhagen, is possible even in affec- tions in which the Trommsdorff value of the centrifugalized cells per 1000 parts of milk is still remarkably slight. The alkaline reaction of affected milk, the altered proportions of mineral salts, at times the passing into the milk of l)loody parti- cles, and the diminution of casein, reduce the coagulability of the milk towards added rennet. Affected milk therefore generally utilizes a considerably larger quantity of rennet than normal milk before it becomes coagulated (Schern). The spontaneous coagulation of affected milk also appears to be considerably delayed. Infectious Agents of Mastitis. Nocard and Mollereau, Kitt, Lucet, Bang, Guillebeau and Hess, Zschokke, Jensen, Streit, Glage and Sven Wall have offered sufficient information regarding the infectious agents of the dif- ferent forms of mastitis. Most cases of mastitis are produced by streptococci; they consist of chronic inflammations of one or more quarters of the ud- der. The disease is of relatively small influence on the general condition of the animal. Bacilli of the coli-aerogenes-paratyphus-paracolon groups pro- duce highly acute, parench^nmatous lesions. The general condition is severely influenced through infections by bacteria of the paratyphus-B group. Locally a gangrenous, septic mastitis de- velops with this infection, and the milk is markedly ichorous, while in colon infections the secretion is of a sermn-like character (Weichel). A third form of inflammation of the udder, also of a chronic nature, is produced by a representative of the group of the BacUhis pyogenes, Sven Wall's pyobacillosis of the udder. The Bacillus pyogenes colonizes with a special predilection in the pres- Streptococcic Mastitis. go eiice of streptococci or staphylococci, and in these mixed infections causes severe necrotic inflammations of the udder, and may con- tinue to produce chronic mastitis in the atfected udder tissue after the disappearance of the other bacteria. Other forms of mastitis are produced by tuberculosis and actinomycosis, and they usually result through emboli of the in- tective agents. _ They may be of a traumatic origin ( actinomycosis ) induced by irritation with particles of straw, or barley beard« +1 ^^^i^^lie^iore all possible infective agents, as for* instance ^^;j • 1 "^ ^/ecrop/?orH5, may be found in inflammations of the udder, either independently or as mixed infections. Only the more important infections of the parenchyma will be described here. Streptococcic Mastitis. . By far the most widely spread type is the streptococcic mas- tisis, described by Sven Wall as streptomycosis of the udder 1 he works of Berg^ey, Craandijk, Trommsdorff and Rullmann, Kunze Russell and Hoffmann, Savage, Riihm, and Ernst give gen- eral nifoiTnation on this condition. The disease is either sporadic or epizootic among the animals of a stable according to the stable conditions Ihe disease may attain an especially wide distribu- tion when the secreiion of the affected quarter is milked upon the floor or into the bedding, and the milkers fail to wash their hands, both bad practices which, it is to be regretted, are quite common. Zschokke Jensen, Bang, and Sven Wall proved experi- mentally that bacteria injected into the cistern penetrate even into the farthest alveoli m from 2 to 24 hours. ^ By inoculating with strains of streptococci of different ori- gin varying reactions may be produced in the udder (Bang- ^^re«- tococciequi^^i^dStrejtococci agalactice; Gminder: streptococci of the stable air and of infectious vaginal catarrh). The manifesta- tions also vary after the injection of individual strains into the same animals, and from injections of the same strain into various animals. In other words the course of the disease varies in ac- cordance with the virulence of the organism, the resistance -L" ^'""a^ '.f lie extent of the local invasioi which agahiis influenced by the lactation period. According to de Bruin fresh milking animals more frequently become affected with the acute torm having inflammatory manifestations, while in old milkino< o^S^ secreh'or''' '''' itself mostly to the altered appearance n.rf^f^r"''/^ ^/i^^''^ '^''^^'^ ^' ^^'^* ^^^iier or later the affected pait ot the gland becomes destroyed. Sometimes the streptococci remain for weeks in the folds of the mucous membrane of the cistern without infecting the par- affPot^^' TT f f 'Tf ^,f "V^^^" ^''^''^ ^^^^^^^^1- qiii^kfv becomes attected. Unfortunately the disease does not often subside even g^ Ert'et't of Iiilcnial lullueuees. through the physiologically cliy period, and the affection re-ap- pears immediately after parturition. The destruction of all streptococci involves a difficult task for the entire body. The dissolution of the streptococci progresses only very slowly even in actively or passively innnunized animals. Living streptococci may be demonstrated in the abdominal cavity of test animals, numy hours after an intra-peritoneal injection. Not infrequently a delayed death appears in apparently recovered animals (v. Lingelsheim). The long strei^tococci appear to rep- resent specially adapted forms which have great tenacity. Never- theless at times recovery takes place. According to Zschokke the? relation between recovered and unrecovered cases is as 7 :5. According to the experience of the author in practice, infectious mastitis is not curable, or only with the greatest difficulty, and if so, always with a loss of productiveness, which even remains after the physiologically dry period. The chronic irritation causes a change in the connective tissue structure of the parenchyma of the udder so that the usual development of the gland during pregnancy cannot take place. The principal aim in treatment therefore should be prompt drying of the suspected udder, in order to make possible the most rapid and most complete recovery, which, ac- cording to Zschokke may be expected only when the quarter has been allowed to remain dry for a long time. This is also necessary in order to prevent a spread of the disease, which is to l)e feared since the hands of the milkers and milking upon the straw may transmit the infective agent to other quarters. Care should be taken therefore to keep the milk from the healthy quarters of the udder separate from the secretion of the affected quarter. As long as the most primitive requirements of clean milk production on the part of the milkers are so carelessly neglected, which unfortunately has been the case up to the present, the im- mediate drying of the affected quarter offers the only means of preventing the further spread of the disease. If, however, there is assurance that the affected animal or the affected quarter, respectively, is individually milked, and the milkers follow instructions, an atteuipt may be made by special frequent milkino^ (into a jar) to produce a hyperemia of the udder. With this method success can only be expected in the early stages. The extent of the spread of the disease may become obvious by the findings after examination of individual herds. In such cases it is necessary to milk each cow, or still better each quarter, separately. The results vary, depending on the technique of the examination. The lowest number of affections is olitained when only a clinical examination is made. This therefore does not suffice in order to eradicate the disease effectively, or to single out the affected animals. The data of the different authors vary relative to its occurrence. The following figures are given which were obtained by systematic examinations of entire herds. Streptococcic Mastitis. 85 Out of 260 animals Trommsdorff found 15.6% affected, Riilmi 31.25% out of 16 animals, Russell and Hoffmann found in 188 sam- ples 50% with ''streptococci." Savage found similar values (55%). The author examined from April 1, 1907, to November, 1908, 1697 samples of milk from individual cows, and found in 348 sam- ples the typical signs of streptococcic mastitis. In 1908 and in the following years he has demonstrated : 1908. No. of animals, 1695. Streptococcic cases 353 1909. No. of animals, 738. Streptococcic cases 301 1910. No. of animals, 597. Streptococcic cases 203 1911. No. of animals, 876. Streptococcic cases 279 Therefore 20.6; 20.9; 40.6; 34 and 31.8%, respectively, of the animals were found to be affected with streptococcic infections of the udder. If the milk of the individual quarters of the affected udder is examined various stages of the affection in the different parts of the udder may frequently be found. Out of 528 quarters of animals with affected udders 276, or 52.2%, showed lesions in individual quarters. 39.2% of the cows had the disease in one quar- ter, 25.9% showed it in two quarters, 18.5% in three quarters, and 16.2% in all four quarters. According to Zschokke out of 662 affected quarters 193 occurred in one quarter of the animal, 211 in two, 109 in three, and 149 in all four quarters. The contamination of market milk with the secretions from animals with udder affections is relatively high. In spite of the fact that proof of the mixing of milk from affected udders with market milk is possible only in very pro- nounced cases (typical streptococcic chains with characteristics of animal origin), nevertheless the following results, obtained in examinations, demonstrated conclusively that the secretion from quarters affected with streptococcic mastitis had been added to the whole milk: 1908, in 352 out of 1578 samples=22% 1909, in 501 out of 1629 samples=40.5% 1910, in 243 out of 1211 samples=20% 1911, in 432 out of 1273 samples=33.9% The hygienic importance of the affection to the consumers of milk may be illustrated from the following data. I. Hoist, in 1894, had the opportunity of examining in Chris- tiania four series of affections of acute gastro-intestinal catarrh. I. Four ^rown persons and four children out of three families in the same street became affected four hours after the drinking of milk which originated upon one farm. Those persons who drank no milk or only that which had been boiled were spared with the exception of a child who became affected, although only slightly, after drinking boiled milk. gg Ef'tVot of Tnferiial Tiifluences, The appearance of the milk showed nothing abnormal, but it coagulated ou lioiling and sliuwed a tremendous number of bacteria, especially streptococci, which could not be distinguished from the Streptococcus piiofienes. The veteriiuiry examination coufinned the suspicion that a ])us-containing secre- tion was being yielded liy one cow. The milk from the cow with mastitis on the ilay in question was a % Easten — 186 samples ."57 % Eastles — 185 samples from all parts of England 75 % The simplest proof of the constant occurrence of streptococci in market milk is the usual acid fermentation of cow milk induced by streptococci. A method for distinguishing- these frequently observed strep- tococci from mastitis streptococci has not yet been discovered, either through the fermentation of various kinds of sugars by the streptococci, or through the investigations of creatinin forma- tions, hemolytic action, acid formation or their actions in the pres- ence of various temperatures of cultivation. It should be borne in mind that the behavior of the various strains of mastitis strep- tococci has been described in such a variety of ways, that either the presence of remarkably numerous strains or a strong instability of characteristics, or confusion with saprophytic forms, must be accepted. The formation of acid by the streptococci is sometimes de- scribed as strong (Zschokke, Nenski, Groning, Kaiser, Heinemann, Miiller, Koning), at other times it appears insignificant (Sven Wall, Rullmann). Lohnic classes the streptococci of mastitis with the group of lactic acid streptococci, especially with the group of Streptococci g until cri, with close relationship to the group of Streptococci rosenbacli, having the following characteristics : "Form of the cells variable; capsule formation is frequent and appears to be as- sociated in certain forms with the presence of sugar in the nutritive media. Spores are not formed; the bacteria are Gram-positive; the intensity of the growth has no sig- nificance. Coagulation of the milk results, in these varieties, either through acid formation or through a rennet-like ferment; gas formation is rare; the pathogenicity varies remarkably." Miiller in his work on comparative examinations of lactic acid bacteria (Typ. giin- theri, etc.) presents the following: 1. "The strains studied manifest marked differences either in their cultural or morphological characteristics with the exception of the strain causing "sour brood" among honey bees. ' ' 2. "The action on carbohydrates is practically uniform." Streptoccccie Mastitis. 89 3. "Influencing individual strains relative to their acid formation in the sense of increasing or decreasing it, is possible. The characteristics which the freshly isolated strains possess are more or less permanent. ' ' 4. "There exists a relation between the group of Streptococcus guntheri and the Streptococcus agalactiae since their capability of forming acid is about the same. ' ' 5. "The oft recurring confusion of the two may be explained by certain similar forms of growth which both possess. ' ' 6. "The supposition that the pathogenic streptococci represents lactic acid bac- teria of the Typ. guntheri which have adapted themselves to parasitic conditions, is sub- stantiated by the findings, since it was possible in the various strains of streptococci to produce transition forms, which correspond to the Typ. guntheri." Therefore from these few examples it may be seen that it is impossible to separate the streptococcus of infectious mastitis from the group of the lactic acid streptococci. Nevertheless it would be a great error to identify the ordinary lactic acid ^ig- ^'^^ streptococci with patho- genic streptococci of man and animals. If the fact is taken into consideration that some streptococci, as for instance that of Kefir, the streptococci of sour milk, and others, have a fa- vorable influence on the nutrition of man, the ne- cessity of their strict identification for control- ling the milk supply is apparent. Although it is not possible to absolutely dif- ferentiate one strain by cultural and biological characteristics, from a culture strain of differ- ent origin, nevertheless there are certain morphological characteristics of the streptococci in the -smears made from sediments, which are sufficiently constant to absolutely warrant the definite assertion that the streptococci in certain positive cases originated in an infected organ, and were not incidentally leading a saprophytic existence in the milk. It has been known for a long time that parasitic bacteria in the animal body, under the influence of the animal's protective strength, attain certain peculiarities of form which they lose under ordinary cultural conditions (under certain conditions it is possible to cultivate capsulated anthrax bacilli). Reference is made to the capsule of anthrax bacilli and to the formation of botryomy- cotic clumps by streptococcic forms. Consideration of the question whether such changes of form in bacteria are developed as protec- Sediment of milk, one day old, from an udder affected with streptococcic mastitis; (a) streptococci of in- fectious mastitis, (b) subsequently developed strep- tococci; 1, 2, 3 and 4, cells from the udder. 90 Effect of Internal Influences. Fiff. tive agents against the ininiunizing jjowers of the body, would re- quire too lengthy a discussion. The fact should suffice that strep- tococci originating from aifected udders almost invariably show signs of such transformation. It is not intended to assert that a steptococcus in milk which does not possess these form peculiari- ties is not a streptococcus of mastitis, or that it does not originate from the udder, and that under abnormal conditions (for instance cultivation at 37 deg. in raw milk or in serum) the streptococci Avhich are present could not undergo changes of form which under certain conditions simulate the forms of ''animal" streptococci; but for normal conditions of milk inspection the morphological characteristics of animal streptococci offer certain definite appear- a n c e s of recognition which have always been joroved by control tests made in the respective stables. These characteristics are the following: The streptococcus takes on a diplococcus- like separation, the cocci apparently press each other, become disc- shaped, and in profile ap- pear like a dash. They stand at right angles to the length of the chain (compare with equine distemper streptococci according to Rabe.) A fine capsule is formed around the "animal" milk streptococci, which is sometimes more, at other times less pro- nounced. This sometimes swells to a broad mucin capsule (com- pare Lingelsheim on streptococci, Wassermann-Kolle's Hand- book of pathogenic micro-organisms III, pp. 309 and 310, and Sven Wall, p. 29). The endococeus, especially in short chains is spherical or swollen to a club shape. With slight practice one almost invariably succeeds in dis- tinguishing, by one or the other given characteristics, the "animal" mastitis streptococci from streptococci which have gained access to the milk accidentally (even though they may also possibly be de- scended from "animal" mastitis cocci). In this way the author succeeded, from April, 1907, to Novem- ber, 1908, in demonstrating l)y the aid of smears that_ secretions from cows with streptococcic mastitis were mixed with market Sediment of market milk in which the typical _ animal forms of streptococci (a, b, c) make possible a diagnosis that tlie milk contains the secretion of an animal af- fected with streptococcic mastitis in spite of the oc- currence of other forms of streptococci (d and e). Streijtocoeeie Mastitis. 91 milk. Out of 1840 microscopically examined samples 336, or 18.26% showed the presence of such an infection. In 91 cases, or 4.945% the changes were not very pronounced ; later control however proved that milk from cows affected with yellow garget had been mixed with these shipments. 18 . 26 % -h 4 . 945 % = 23 . 205 % , proved contaminated with streptococcic pus out of 1840 milk samples. Miiller intended in his work to distinguish milk streptococci, especially the streptococci of mastitis, from strains of streptococci pathogenic to man. In confirmation of the work of Nieber, Fischer and Berger, Miiller came to the conclusion that the I'ie- 19. recognition of milk strep- tococci pathogenic to man is impossible. Although milk streptococci as a rule coagulate milk some- what more quickly, there are also strains which coagulate milk somewhat more slowly, and strains which dissolve the blood cells in Schottmiiller 's blood agar, and these in their agglutination value stand very close to the pathogenic streptococci of man, that is, they ag- glutinate even in dilu- tions of the serum of 1:400—800. At the same time several of the abso- lutely pathogenic strains fail to give any agglu- tination, and other ap- parently saprophytic va- rieties give a higher ag- glutination value. Bau- mann proved that there is no uniform agglutination value of the individual kinds of streptococci, and that spontaneous agglutina- tion frequently appears in tests of their cultures. Together with Horauf, the author found that mastitis strains show similar characteristics on Schottmtiller's blood agar to the less pathogenic strains of man, a fact which has recently been con- firmed by Gminder. Lingelsheim makes the statement that strepto- cocci producing toxins are always obtained from subacute and chronic processes. Acid formation and milk coagulation are common to the entire Sediment of red milk. Many red blood corpuscles, several polynuclear leucocytes and colostral cells. Streptococcus brevis with capsules. 1 X 1000. 92 Effect of Internal Influences. Fio-. 20. group of pathogenic streptococci. Of the pyogenic strains of man, according to Andrewes, the iStreptococcus pyogotes and the Strep- tococcus viitis produce acidity without coagulation. Sven Wall proved these characteristics from the mastitis strains isolated by liim. According to Adametz, the mastitis cocci sometimes coagulate very intensely, the same as is the case with the streptococci of enteritis of sucklings (Petruschky). The fermentation in various sugars using Gordon's bouillon mixtures, varies greatly with the different pathogenic streptococci and milk streptococci, so that the possibility of differentiation by this means is quite impossible, which is likewise the case by testing their virulence on small test. animals. Pathogenic strains may at times show great variations of viru- lence, while according to Heinemann strains of the Streptococcus lacticus may become virulent by passage through rabbits, until they Avill produce changes in rabbits which correspond in their ap- pearance, extension and character, to those caused by pyogenic strains re- covered from man. Through their action on animal bile, or on sodium taurocholate, M a n d e 1- baum differentiates the Streptococcus miicosus and Pneiimococcus from Streptococcus pyogenes and other streptococci (Neufeld, V. Levy). The author used the mastitis Sefliment of milk from an udder with acute inflammation. straiuS llC had OU haud Short forms of streptococci. 1 X lOoi). ,,-, -• -, -i on cattle, hog, horse and chicken bile, but failed to observe either a clearing of the culture media or an influence upon the form and appearance as shown by the microscope. The establishment of the ''virulence number" through phag- ocytic experiments also fails to yield the desired result. In short up to the present time the absolute separation of culture strains of varied origin, the differentiation of saprophytic streptoccoci from mastitis streptococci, and these from pathogenic streptococci of man has not been successfully accomplished. We have, however, in certain morphologic indications, for instance streptococcic Mastitis. 93 the cross-position of the segments, the capsule-like covering and other characters, a way of distinguishing streptococci originating in the udder of an animal from such as have subsequently gotten into the milk. If these distinguishing signs are present then smears from the sediment of market milk permit the deduction that secre- tion from an affected udder has been included in the milk. If, on the other hand, these signs are not present in the streptococci of the milk, it cannot be asserted that the milk is not contaminated with the secretion of affected udders, it is not Fig. 21. Although IS known what factors (streptococci, toxins, in- flammatory products) convey the unwholesome- ness to the milk, and al- though in spite of the fre- quent occurrence of mas- titis injurious effects re- sult with relative rarity, nevertheless the secretion from udders affected with streptococcic mastitis, and mixed milk which is contaminated with such secretion should be con- sidered capable of im- pairing the human health, since 1. There are known cases in which severe dis- turbances of health re- sulted from the ingestion of such milk. 2. The investiga- tions of streptococci scientifically justify the suspicion of harm arising from their ingestion. What are the conditions of the mastitis streptococci among themselves? Formerly a Streptococcus hrevis and a Streptococcus longus were distinguished, but it was shown that these distinguish- ing features were not absolute (Staeheli). The differences of the in- dividual strains and the forms of their growth in culture are as in- constant as their pathogenicity, acid formation, and other biological characteristics, so that, as expressed by Kitt, it would be necessary to distinguish as many varieties as there are mastitis cases if it was desired to accept the differences of the individual mastitis strains as indicative of different varieties. All the smaller and greater differences should be considered as indications of adapta- ^.f •:^ ( i £ cj ^ '^^^^^^ES^^ •^ ^^ ;v? '^' '^"^ f^^^^^^B /'/^ »% ^ " •■ff-1>'>X's| 7 K'-^V i k » " - *r. ^\ %! ^ p <■ •''i *- \. '- * \ n. '- . '. k I I \ A / * 'O. •C-* *;-f ^*w»* f'' , ^ • %--^ < } 'l -^ , J ~> Streptococcic pus from milk of a cow with streptococcic mastitis. Streptococcus longus. 1 X 1000. 94 Effect of Internal Inlluenoes. tioii to the various energies of reaction of the various animals and organs, and as the investigations of the author showed, to energy reaction of the same milk ghmd at different times. For instance it appears that certain changes in form liear a definite rehition to the number of leucocytes in the milk. Thus the author obtained the following results in the same quarter of a cow examined at dif- ferent times : L. — Leucocytes. Sir. — Streptococci. Dec. 17, 19ns. Jan. 4, 1909. Jan. 20, 1909. Jan. 2o, 1909. Cow Xo. 29 L. 8tr. L. Str. L. Str. ].. Str 1 rio-htfore 0.3 .1 0..5 0.2 2 left fore 0.2 0.9 Bipl. 0.4 brevis 2.0 hrevis 3 rii-ht hind 500.0 longiis 2.0 brevis 1.9 brevis 3.0 brevis 4 left Ivinil 500.0 longus 20.0 longus 0.5 brevis 10.0 longus Cow Xo. 34 Dec. 17, 1908. Jan. 5, 1900. Jan. 1('>, 1909 Jan. 29. 1909. 1 right fore 0.1 0.2 0.1 0.2 2 left fore 0.2 Dipl. Drops 0.3 0.5 3 right hind 0.4 Dipl. 0.3 Dipl, 3.0 longus 50.9 brevis 4 left hind 0.3 Dipl. 0.5 brevis 4.0 longus 60.0 brevis Dec. IS, 190S. Jan. 4, 1909. Cow Xo. 31 L. Str. L. Str. 1 right fore 0.5 Dipl. 0.3 brevis 2 left fore 1.5 200.0 medium sized 3 right hind 1.2 Dipl. 1.8 brevis 4 left hind 1.3 brevis 0.9 Dipl. Cow Xo. 33 1 right fore 2.0 brevis 0.3 Dipl. 2 left fore 0.5 0.2 3 right hind 1.3 brevis 20.0 longus 4 left hind 0.9 brevis 10.0 longus Cow Xo. 58 Dec. 19, 1908. Jan. 5, 1909. 1 right fore 0.1 0.5 Dipl. 2 left fore 0.4 brevis 0.3 Dipl. 3 right hind 0.3 0.1 4 left hind 0.1 0.1 These differences in the forms of streptococci may be seen dur- ing one milking on the same animal, if they are compared at the beginning, the middle and at the conclusion of the milking. These differences are only slight, so that no definite conclusions should be drawn from them. If however the results from various animals are compared it may be seen, as already indicated above, that certain relations exist between the number of leucocytes and the forms of the streptococci since the streptococci become longer as the number of leucocytes increases. The experiments extended from December 11, 1908, to February 8, 1909, and include three stables with a total of 149 cows. Of these 149 cows 59, or 39.6% were more or less affected. In most animals (140), all quarters were separately examined and Streptococcic Mastitis. 95 showed that out of 560 quarters 112, or 20% were affected. Forty- two of these gave at tmies a greater, at other times a smaller secre- tion with a distinctly changed consistency. The other 70 manifested the infection only after sedimentation, or only through microscopi- cal examination. Some of these 12 quarters were successively (see above) examined, so that the material used for smears from af- fected quarters, and which had been microscopically examined, amounted during the period mentioned, to 134. Fifty-five affected quarters showed the Streptococcus hrevis, 32 the Streptococcus longus; in 47 the infective agent was recog- nized in the form of a diplococcus. The 47 quarters with diplococci had as a rule a very small leucocytic number. In values of over 2.0, longer coccus-chains were always observed. 32 quarters out of the 47 had . 5 :1000 leucocytes 12 quarters out of the 47 had 1 .0 :1000 leucocytes 3 quarters out of the 47 had 2.0 :1000 leucocytes In the 55 cases with Streptococcus hrevis the change in the leucocytic number varied to a greater extent. In 18 it represented 0.5:1000 or 32.73%. In 14 it represented 1.0:1000 or 25.47%. In 8 it represented 2.0:1000 or 14.55%. In 3 it represented over 2.0:1000 or 5.45%. In 12 it represented 5-20 and more :1000 or 21.82%. The 32 longus-cases were divided as follows : Leueocytic Quantity. Number of Cases. Percentage. Under 0.5:1000 1 3 125 up to 1.0:1000 1 3 125 up to 2.0:1000 3 9.375 up to 5.0:1000 3 9.375 up to 20.0:1000 3 9.375 up to 100 and more:1000 21 65.625 In other words : In leucocytic quantities Tip to 0.5, 63.00% showed 85.0% brevis, 2.00% Dipl. longus Up to 1.0, 44.40% showed 51.9% brevis, 3.70% Dipl. longus Up to 2.0, 17.65% showed 64.7% brevis, 17.64% Dipl. longus Up to 5.0, 0.00% showed 50.0% brevis, 50.00% Dipl. longus Up to 20.0, and more 0.00% showed 33.0% brevis, 66.60% Dipl. longus The leucocytic values will be taken up again later in the dis- cussion of the "Trommsdorff" test. _ From this tabulation it may be seen that the length of the chains actually grows with the increase of leucocytes, or with the amount of sediment. In high leucocytic values and short forms of the infective agents, the latter are frequently present in exceed- ingly large qantities. The opinion that the form of the streptococcus represents an adaptation to the energy reaction of the respective animal and or- gan is thereby substantiated especially when the streptococci are J)() Effect of Inlenial Inlluences. found in the secretion of one and the same ])ai't of the udder of a cow at different times. In the same way it is impossible to establish rnles for definite differentiation of the strei)tococci of the yellow i>aroot amon,^- them- selves throni^h the stndy of their niorpholoi>ical relations, by com- parison of their biochemic characteristics or the pathogenic viru- lence of individual strains, since the acid production and acid susceptibility which are present in mastitis streptococci at first may be easily changed by artificial means, and individual strains have proven the possession of stronger, others a weaker pathogenic action for test animals (Groning, Sven Wall). The author does not desire by any means to establish a theory of unity for mastitis streptococci. To be sure there are marked differences in the various strains, especially in regard to the pro- duction of clinical symptoms, which cannot be attributed alone to the variation of virulence, and to unequal resisting powers. It is possible that with the aid of newer methods of differ- entiation (blood media, etc.) it will be possible to establish a fun- damental type of mastitis streptococci in strains freshly cultivated from animals. Even if with the continuance of cultivation new characteristics, as for instance hemolytic properties, may be acquired by the cultures, and the earlier characteristics become lost, the characteristics acquired by the respective strains of streptococci in their former growth may remain constant for a sufficient length of time to permit the establishment of the type of varieties, as has already been the case with the streptococci of man (Petruschky, Schottmuller, Baumann, Schulze and others). Enrst, Gminder and others have demonstrated that the mastitis streptococci mostly correspond to the mitior sen viridans or mucosus hom. group, respectively. Based on the grounds previously described, milk hygienists, bacteriologists, children specialists and veterinarians sometimes more and at other times less imperatively have demanded the ex- clusion of cows with streptococcic mastitis from the production of milk (Jensen, Weigmann, Rievel, Sven Wall, Euhm, Trommsdorff, Seiffert, Ernst and others). This requirement is natural from the hygienic standpoint, but its practical execution is rendered very difficult by the remarkable prevalence of the disease, and as a matter of fact as long as the general control of production and the examination of milk of indivi- dual cows are not required a thorough enforcement cannot be hoped for. For the present the exclusion from the market of all milk which shows changes in a recognizable way, as for instance through a collection of yellow sediment, should be considered satisfactory. At the same time from an economic standpoint only milk from affected quarters should be excluded, while the sale of milk from healthy quarters should be allowed. Udder Tuberculosis. 97 TUBERCULOSIS. Occurrence of Tuberculosis in Cattle. Tuberculosis of the udder in cows appears with relative fre- quency, corresponding to the frequent occurrence of tuberculosis in cattle. Tuberculosis in the udder is manifested in different forms, the circumscribed, lobular, focal tuberculosis and the diffuse tuber- Fia-. 22. im Wa)>^in, may occasionally be infected with tubercle bacilli; all milk in the production of which no special care is taken in the selection of the milking animals and no clinical examination or tiibercnlinization of the animals has been undertaken, should l)e suspected of contain- ing tubercle bacilli, and the larger the herd which produces the milk, the greater the danger. German investigators established the following tigures for the presence of tubercle bacilli in market milk: riaee. TuIk rcular %. Berlin 61 Halle 33.3 Berlin 14 Berlin 30.3 Market milk Berlin 55.5 Dairies nnder veterinary control .. 0. Danish milk ." 38.5 Leipzig 10.5 [The percentage of tubercle bacilli found in the milk supply of large cities in this country has been accurately determined in only a few instances. In 1907 Anderson proved that in Washing- ton, D. C, 10.7% of the dairies supplied milk containing virulent tubercle bacilli, Schroeder found 7.7% of the 26 dairies examined w^ere distributing infected milk to Washington, D. C, while still later Mohler showed that abont 3% of the 73 samples of milk ex- amined contained tubercle bacilli. The apparent discrepancy in these results may be readily explained by the fact that during the last 6 years strenuons efforts have been carried on by the Bureau of Animal Industry to eradicate tuberculosis from among these herds, ■with the result that in the District of Columbia the number of tuberculous animals has been reduced from 18.8^0 to 1.2% in 1914. Hess has found that 17, or 16%, of 107 samples of milk dis- tributed in New York City contained virulent tubercle bacilli, while Campbell made extensive investigations of the occurrence of tubercle bacilli in the market milk of Philadelphia, and found 18 or 13 .8% of the 130 samples examined to contain living bacilli of tuberculosis. — Trans.] Under What Conditions Do Tubercle Bacilli Enter the Milk? The infection watli tul)ercle bacilli is natural when the animal is affected wdth tuberculosis of the udder, or may occur indirectly wdien through contamination of the udder wdtli feces in pulmonary or intestinal tuberculosis, urine or vaginal secretion in kidney or uterine tuberculosis, or Avith infected straw, tubercle bacilli are brushed off from the soiled udder into the draw^n milk, or when in Infectiousness of Milk. 101 open tuberculosis of the lungs the bacteria get into the milk through the air or straw. As early as 1869, prior to the discovery of the tubercle bacil- lus by Koch in 1882, Gerlach proved the infectiousness of milk from highly tuberculous animals through feeding and inoculation experiments. This was also emphasized by Ziirn, Kleins, Sommer, and in 1880 by Bollinger, who first pointed to the fact that the milk of a tuberculous cow in which the udder is not noticeably affected may contain tubercle bacilli. The same results are shown by the works of Stein, Bang, Hirschberger, Ernst, Schroeder and Fiorenti, Avho succeeded in producing tuberculosis in test animals with milk of tuberculous cattle, even though there was no udder tuberculosis jDresent. Milk from tuberculous udders always has lieen proved to be especially dangerous (May, Bang). If special care were exercised in milking, it not infrequently happens even in extensive, generalized tuberculosis that the in- oculated animals remain well; thus Xocard from injecting milk of 54 cows affected with generalized tuberculosis succeeded only in 3 cases in producing inoculation tuberculosis. Therefore it ap- pears that in spite of a generalized tuberculosis when udder tuber- culosis is not present, tubercle bacilli are not always excreted with the milk; the possibility of elimination however, that is, that the milk of such a tuberculous cow may contain tubercle bacilli, should at all times be given consideration. Is milk liable to be affected when tulierculosis cannot be clin- ically demonstrated in suspected cows, or when they appear healthy and yet react to tuberculin! Are tubercle bacilli eliminated only with the milk from animals affected with tuberculosis of the udder, or also in cases where the udder is not affected by tuberculosis! These questions may be answered at the present time with great certainty, namely, that tubercle bacilli of cattle are eliminated with the milk as a rule only in animals which are affected with tubercular mastitis. This question is of especial interest in the eradication of tuberculosis in the dairy herd, since it is well known that calves and hogs are highly susceptible to the tubercle bacillus of cattle. It will be advisable therefore to refer to the more important publica- tions on the elimination of tubercle bacilli with the milk, before entering into the c{uestion of the harmfulness of such for man. Delepine, Eavenel, Eabiiiowit?ch aud Kempner, Gelirmanu, Gehrmann and Evans, Moiissu and Mohler obtained positive results from milk of animals not clini- cally affected, but reacting to the tuberculin test, through inoculating or feeding of test animals. Other investigators, as Martel and Guerin, also Hirschberger, aimed to solve the qnestion by inoculating the milk of slaughtered animals or glandular substance from ndders of reacting animals. Their work also frequently gave positive results. ^7? of ihese authors therefore, conclude icith great certaintii that tubercle hacilli maii he eliminated icith the milk even from animals u'hich are not clinicaUy afected with tii- herculosis. Other views are supported by Ascher. Muller, Ostertag. Stenstrom, McWeeney, Pusch and Hessler as the result of their negative findings, namely, if the experiments were conducted under the most painstaking requirements and all contaminations through 102 Tuberculosis. infectoil straw, etc., u\M-e avoiilcil as imich as possihio, tlu\v failed in spite of numerous pvperiifeiits in proiiuciiio- tul;ortni)osis with milk from a tuherculiii reacting animal, and fi(M|ueiitly not even with the milk from an animal clinically affected, but free from tuberculosis of the udder. From the standpoint of milk hygiene the fact is important that in the work of tuberculosis eradication by the agricultural societies the examinations for tubercle bacilli in the mixed milk of individ- ual herds were mostly negative after the clinically affected tuber- cular animals had been eliminated. According to the works of Muller and llessler until July 1907, 2,949 samples of mixed milk of individual herds were examined; all of these herds were sub- jected to the Siedamgrotzky-Ostertag method of eradication. From .■)0 to 200 cows particii)ated in each test and 156 herds gave milk free of tubercle bacilli. As eliminators of tubercle bacilli were found : Two cows with udder tuberculosis, 8 times each. One or more cows with tuberculosis of the uterus, 16 times. One or more cows with tuberculosis of the uterus, 6 times. Once kidney and uterine tuberculosis. Once pulmonary and intestinal tuberculosis. Once a cow whose saliva contained tul)ercle bacilli and 19 times open pulmonary tuberculosis. In five positive tests there was no clinically demonstrable form of tuberculosis, and the subsequent tests of immediately drawn con- trol samples remained negative. These five cases were observed in the beginning of the eradication work. Tlie remaining 2,793 milk samples were free of tuberculosis in spite of the fact that among tlie animals of these herds there were surely a great number which would have positively reacted to tul)erculin tests. The five cases observed at the beginning of the eradication work, in whieli the milk contained tiihercle bacilli, altliough elinicallv o])en cases of tuberculosis could not be found on stalile examination, are explained by Hessler in that the milk liecame contami- nated with jiarticles of the feces from pulmonary cases of tuberculosis, which had not yet developed clinically. This is also suggested by the smaller number of bacilli found in the milk. Tu1)ercle bacilli therefore occur in the milk in great numbers when animals with open tuberculosis, and tuberculosis of the udder stand in the stable. Milk from animals which manifest their tuber- culosis by a positive tuberculin reaction, will usually be free from tubercle bacilli. Such cows belong to the least dangerous class. Nevertheless the investigations of Eabinowitsch, Kempner, Eav- enel and others, who obtained positive inoculation results with milk from reacting animals, prove that such milk may at times contain tubercle bacilli in small numbers. Ordinarily however this will uot be the case, and the milk of such animals may, as a whole, be considered free from tubercle bacilli. Therefore it appears evident that under present conditions of milk production the ingestion of tubercle bacilli with milk is possi- ble at almost all times. Tubercle Bacilli Types. 103 What Danger Threatens Man Through Ingestion of Milk Which Contains Bovine Tubercle Bacilli? In order to answer this question it is necessary to refer to the development of tuberculosis in man, and to consider the fac- tors which are necessary for an infection of his body. These factors in addition to the toxicity of the infective agent, and the quantity in which it has the opportunity to enter the body, depend upon the avenues of infection which it takes and the local and general resistance of the attacked individuals towards the spe- cific infective agent. There is perfect agreement relative to the virulence of the bovine tubercle bacillus for man. The bovine tubercle bacillus is a strain of the tubercle bacillus with such pregnant characteristics that it is almost invariably possible to classify it separately from other strains when obtained in culture, that is, to distinguish the bovine tubercle bacillus from the bacillus of the human type. These bacilli are distinguished as the typus bovinus and typus humanus (only these two types need to be considered from the standpoint of milk hygiene) which are characterized by the fol- lowing peculiarities : Typ. Bovinus. The growth is delicate and in the thin film small wart-like colonies develop; on bouillon a mesh-like fine membrane with wart-like prominences develops proliferating downward, or a membrane of tissue-paper thick- ness results ; the bouillon is probably neutralized and finally becomes alkaline. The bovine tubercle bacil- lus is as a rule of greater toxicity for smaller mammalia. Rabbits develop through intra- venous injections of the bacillus (0.001 gm.), a generalized tu- berculosis from which the ani- mals succumb inside of three weeks. When 0.01 gm. is in- jected under the abdominal skin, it produces in a short time, gen- eralized tuberculosis. Cattle succumb readily to Typ. Humanus. The growth is a luxuriant, uniformly thick and wrinkled membrane, which proliferates on the wall of the tube. The growth is the same in bouillon; the degree of acidity of the bouillon is usually at first diminished, later increased. 0.001 gm, of bacilli of the human type intravenously in- jected produces after months only a chronic form of tuberculo- sis (joints, kidneys, lungs, testicles). The injection under the ab- dominal wall produces only local lesions. Inoculated into cattle the bacilli of the human type (0.05 gm. subcutaneously), produce only slight or no pathogenic ac- tion. The process remains local, and extends only to the 104 Tuberculosis. infection witli the typus bovin- ns, from an extensive form of tnberenlosis. Guinea pigs die more quickly from an inocula- tion with bovine tubercle bacilli than from an inoculation with the bacillus of human type. neighboring glands; a great healing tendency prevails. Intravenous injections of 1 mg. of the typus humanus into the vein of a mouse will show it to possess a greater resistance than when inoculated with the typus bovinus. Ill the last 10 years about 2000 strains of tubercle bacilli from man anil cattle have been cultivated and studied. In these studies even further differences were found Avbich, however, are not as constant as those given above; for instance, the bacillus of the human type in glycerin bouillon cultures is delicate, slender, slightly curved, and of beaded staining qualities, whereas the bovine strain is regular, plump, thick without granular difl'erentiation in staining, and frequently with swollen ends. The pigment formation on glycerin potato is more typical of the human type than the bovine type. The former when placed on serum in hermetically sealed glass tubes remains viable for twelve months, the latter for over a year. Contrary to the views of many investigators of tuberculosis, Nocard, Hueppe, Von Behring, Eomer, de Jong and others support the theory that the tubercle bacillus adapts itself to the infected animal and becomes transformed as a result of its environment. Eabinowitsch, Dammann and Eber have also supported this trans- formation theory. The latter especially attempted to prove by ex- tensive experiments and investigations that Bacilhis liumcoius, by passage through cattle, changes into the bovine type'. This question however appears at the present, to be decided in favor of the stability of the bacillus. Tt has at least been shown with six various strains of the human type, that in passage experiments through 2 to 7 cattle, in from 247 to 512 days, the character of the bacillus was not changed (English Commission and Weber), and that bacilli of the human type by eight subsequent passages through goats, in 516 days, and l\v four passages through cattle in 685 days, were not influenced in their typical characteristics. The immunization experiments which were undertaken with the bacillus of the human type on cattle showed no changes whatsoever in the human type after the pres- ence of the bacteria in cattle for a year and seven months (Baldwin) in spite of their ])ropagation in the udder of the cow. The same results were obtained in three experi- ments by Weber, Titze and Joern, who allowed the bacillus of the human type to exist in the body of cattle for two years and one month and for two years and six months. Eber 's experiments found no confirmation in the Imperial Board of Health; the experiments however are being continued in strict co-operation with Eber. On the contrary it is shown that the bovine bacillus constantly retains its characteristics within the human body. From a boy who was affected since his second year with tuberculosis of the fourth digital bone of his hand, it was possible during surgical interference to obtain material from the same place at five different times, during his age from 8 to 13 years. The in- fection was caused by the bovine bacillus. In spite of their existence for ten and a half years in the human body these bovine bacilli had retained their characteristics. A marked influence in their virulence was manifested, however, since the bacilli, from the second operation, in quantities of 2 mg. could no longer kill rabbits even after intravenous inoculations. From the sub- sequent operations it was found that the virulence was again increased. Griffith obtained the same results with bovine cultures from lupus from which the bacilli were isolated six months, two and three and a half years, respectively, after the first examination. Tt is true that the virulence was several times lower than is or- dinarily the case with the bovine type; the other characteristics of the strain however Transmission of Bovine Tuberculosis. 105 were tenaciously retained. In one of the eases the bacillus persisted in the hnman body for 18% years. Passage through rabbits and cattle again increased its virulence. Al- though through animal passage a change of the virulence is possible, nevertheless this change results only inside of the borders of the type and in the direction of the type. The bovine bacillus therefore does not pass into the human type, nor the latter bacillus into the bovine type. Only a brief statement will be made relative to the so-called atypical strains. It has been demonstrated that there are cultural strains which cannot be classified as belonging either to one or the other type (Kossel, A¥eber and Heuss, Lydia Eabinowitsch, de Jong and others). These strains proved to be mixed cultures of both types. In the same person not only mixed infections of both types may exist in the affected organs, but also a double infection may occur in such a way that in one organ the Typus humamis, and in the other organ the Typus hovimis, may be found in pure culture (Weber, Weber and Taute, Grriffith, Park and Krumwiede, Steffenhagen). In 1901 Koch explained at the International Tuberculosis Congress at London, that tuberculosis of man is produced by a tubercle bacillus which differs from the bovine tubercle bacillus, and expressed himself as opposed to the general prevailing opin- ion of that time, regarding the great danger of the cattle tubercle bacillus for man, and as believing that the transmissibility of bovine tuberculosis to man was so slight compared with the dan- ger which threatens man from tuberculous human beings, that its practical importance was negligible. Although Koch's statement cannot stand in the directness of his declaration, nevertheless at the present time it is generally accepted from the above mentioned differential characters, that marked differences exist between the bacillus of bovine tubercu- losis and that of man, and it is a fruitless work to dispute whether they are differences of varieties or peculiarities of the different strains, which lead to the variations, if we accept the fact that the differences of the strains are obstinately retained. The results are of especial value in differentiating the two types of tubercle bacilli. In association with Shtitz, Koch under- took some experiments to establish points of differentiation. Nineteen calves which were infected intravenously, subcu- taneously, intraperitoneally, by inhalation or feeding experiments \\ii\ii\iQ BacillKs humamis, showed no manifestations of disease, in- creased in weight, and on autopsy conducted several months after infection, showed only caseous purulent changes at the point of inoculation. On the other hand, after the inoculation of bovine tubercle bacilli, severe febrile symptoms and extensive tubercu- losis, especially of the lungs, liver and spleen resulted. The same results were obtained from the experiments of Kossel, Weber, Heuss. Bacilli of the human type were retained in the regional lymph glands ; the changes induced by them gradually retrogressed, whereas infection with the bovine type of the bacillus led to a pro- 106 Tuberculosis. gressive tuberculosis. Iiilialation and feeding experiments showed the slight virulence of the human tubercle bacillus for cattle. In the experiments of Nocard, Meyer, Calmette and Guerin and Zwick, the inoculation of tubercle bacilli of bovine origin into the milk ducts resulted in a tuberculosis of the udder with rapid enuiciation of the animal, terminating in death ; whereas the bacilli of human origin produced only a passing inflammatory irritation, and an interstitial atrophy of the udder. Calves which nursed on these latter infected udders remained healthy (Zwick and Maier), or on the other hand (in one case of Zwick) intestinal tuberculosis, Avitli tuberculosis of the mesenteric lymph glands, developed. At autopsy undertaken 20 weeks after the infection, the ndder of the cow showed atrophy with miliary tulierculosis, without however typical tuberculous changes in the regional lymph glands. From these results the conclusion may be drawn that tubercle bacilli of human origin are only very slightly dangerous for cat- tle. It should be considered however that occasionally after artifi- cial infections the bacilli may persist in the infected region, with or without marked local or at times even generalized changes. Calves may develop intestinal tuberculosis or tuberculosis of the mesenteric hnnpli glands as a result of ingesting a large amount of tubercle bacilli of the human type. Almost the same relation exists in man towards the bacillus of bovine tuberculosis. The principal dangers threatening man are through the possibility of infection from affected human beings, and less so to the possibility of infection with diseased products of animal origin, as for instance milk. The possibility of tuberculosis infection through animal products is presented with remarkable frequency, as may be seen from the above statements; still the rarity of infection with the bovine type is quite striking. Hogs which become readily infected with the bovine type are very frequently af- fected by the ingestion of skimmed milk containing tubercle bacilli. In northern Germany some of the herds show an infection of 50-60, occasionally even up to 90'/f . The experience at the tuberculosis eradication stations indicated that by the elimination of cattle affected with open tuberculosis a marked reduction was obtained in tuberculosis of hogs, and that this measure in association with pasteuriza- tion of the skimined milk, offers a certain remedy against the spread of tuberculosis of hogs. The same opportunity which is afforded hogs to contract tubercle bacilli from the feeding of skimmed milk, would apply to man. The relative infrequency of the infection of man with the bovine type of tubercle bacillus is not the result of a milder virulence of the bacilli but is due to the previous boiling of the milk. Convincing observations have also been made on this point. However before entering into a discussion of these, it will be advisable to illustrate further the possibility of infection for man from the standpoint of the port of entry, and also show the relative condition existing between the necessary infective quantity of bacteria and the establishment of the disease. Insestion Tuberculosis. 107 The development of the affection depends on the most varied conditions, on the quantity of the introduced virus, condition of the port of entry, general resistance, etc. Frequency of Tuberculous Infection Through the Alimentary Tract. If the lesser virulence of the bovine type for man, as compared to the human type, is left out of consideration, which fact is con- sidered satisfactorily proven, the experiments of Ostermann, Schroeder and Cotton show what great quantities of infectious ma- terial are necessary in order to produce tuberculosis by ingestion. Schroeder and Cotton fed milk artificially infected with tuber- cle bacilli, and proved that infected milk which invariably produced tuberculosis when inoculated intraabdominally in 5 c._ c. doses, could be fed for 30 days without causing the disease in the ex- perimental animals. The dilutions were prepared (1) by adding one platinum loopful of a cloudy sus- pension of tubercle bacilli to 10 e. e. of milk. (2) by adding one loopful of the orig- inal suspension to 10 c. c. of sterile water, and of this dilution one loopful was placed into 10 c. e. of milk, (3) by adding one loopful of the original suspension to 100 c. c. of sterile water and of this dilution one loopful was placed into 10 c. c. of milk. It was not possible to produce ingestion tuberculosis with either the second or third dilution during the period of the experiment, although the dilutions were not as high as they occur in the milk of tuberculous animals (with the exception of tuberculosis of the udder). Ostermann by comparing the average number of tubercle bacilli in cow's milk with the minimal dose necessary for producing ingestion tuberculosis in guinea pigs, rabbits and goats, came to the conclusion that an alimentary infection is exceedingly rare. Nevertheless the danger of an alimentary infection with bovine tubercle bacilli, even in high dilutions of the tuberculous material in market milk, cannot be disregarded. The danger of infection to which small children are exposed from the ingestion of food (without attempting to distinguish "bo- vine tuberculosis" from "human tuberculosis") is best illustrated by the clinical cases and also those cases of intestinal and mesen- teric tuberculosis which are found on autopsy. Edens, from October 1, 1904, to September 30, 1905, found 12%, and from this time until September 30, 1906, 13.6% of the bodies of children which he autopsied at the ages of 1 to 15 years, affected with primary intestinal tuberculosis or tuberculosis of the mesenteric lymph glands, whereas in man from 15 to 19 years of age only 3.8% and 2.6%, respectively (all autopsies), showed the disease. The intestinal tract of children appears therefore to be a prominent port of entry for the tubercle bacillus, which is also proven by the works of Orth, Henke, Chiechanowski, Hamburger, Nebelthau, Lubarsch, Bruning, Fibiger and Jensen, S;^anes and Fischer, Price and Jones, Kingsford, Harbitz, Og-^^da, Edens, Wagener and Heller, who demonstrated primary intestinal tuber- JOS Tuberculosis, culosis in varying proportions, np to 47.6% of the tuberculous cliiklren. The frequency, however, with which tu))ercle l)acilli actually pass through the intestinal wall without producing demon- strable changes in the intestines and mesenteric lymph glands cannot be stated. The intestinal tract may be the avenue of infection without itself or its regional Ijanpli glands becoming in- fected. The percentage given above shouhl therefore be higlier. The works of McFadyean, MacConkey, Plarbitz, Weichsell)aum, Bartel, Rosenberger, Raljinowitsch, Ipsen and others offer proof for this contention, as they mention cases in Avhicli apparently healthy mesenteric lymph glands contained tubercle bacilli wliicli although ap])earing to be in a latent form at the time of finding, ])roduced tuberculosis when inoculated into experimental animals. It appears also to be proven experimentally that through the feeding of tuberculous material tuberculosis of the lungs may develop without the presence of intestinal tul)erculosis or tuber- culosis of the mesenteric glands (Bartel, Bongert, Kovacs and others). In this regard the question may be raised as to whether there is any possibility of the tubercle bacilli working up from the intestines into the esopha£>iis, and into the buccal cavity, from which inhalation tuberculosis could result (Uffenheimer, Dieterlen). This objection would not enter into consideration for the pur- pose of milk control, since it is immaterial for the hygienist work- ing along practical lines, whether the infectious agent causes dis- ease in the body by way of the circulation or through inhalation. In this instance it is only necessary to keep in view preventive measures, which should completely prevent the body from com- ing in contact with producers of the infection. Alimentary Infection of Man With Bovine Tuberculosis. After the supposed cases of transmission of the bovine tuber- cle bacillus cited in former years failed to withstand critical observations, Koch at the International Tuberculosis Conference, held in Berlin, in 1902, urged the following up of all cases of established tuberculosis of the udder, the determination of how long the disease persisted, who consumed the milk and milk pro- ducts from these cases, whether the milk had been boiled and whether the respective persons became affected with tuberculosis. This request was fruitful of results, and in 1910 Weber pub- lished the results of his compilation investigations, whicli wore carried out by the aid of official statistics from Prussia, Bavaria, Saxony, Wurttemberg, Baden and Hessen. The investigations extended over the time between the ])e- ginning of 1905 to April, 1909; the investigation of some of the individual cases however is still being continued, since in the chronic courses of tuberculosis it must be considered that the Bovine Tuberculosis in Man. 109 results of infection with bovine tubercle bacilli may under certain conditions only manifest themselves after years have elapsed. In the given period 113 cases were reported, of which 68 were from Prussia, 14 from Bavaria, 6 from Saxony, 6 from Wurttem- berg, 10 from Baden, and 9 from Hessen. At least 628 persons came under consideration in the inges- tion of such milk, possibly even more, since at times only the term ''family" is designated, and the milk was not infrequently deliv- ered to dairies with a large patronage. These cases were not in- cluded, although every person is exposed to an infection w^ho par- takes of such milk and dairy products. In the case of 9 persons no age is given; 284 were children, and 385 adults. The value of the individual cases must of course be judged in different ways. In 44 cases it is stated that the milk had been consumed only as an addition to coffee, or mixed with milk of healthy animals, or the data were otherwise not accurate. Of especially great interest are those cases in which it was emphasized that the milk was consumed in a raw state, unmixed, mixed with milk of only a few cows, or in which such milk was used in the preparation of butter, buttermilk, sour milk, or had been consumed for a long period. In such cases tremendous num- bers of tubercle bacilli must have been taken into the digestive tract. According to Bang and Wall the milk from tuberculous udders may retain a normal appearance for months, being used as food without any objection, and yet such milk contains millions of tubercle bacilli. Bang found in smear preparations of such milk, in a single field as many as 200 bacilli. In all 69 cases were reported, in which it was stated with cer- tainty that raw milk of animals with udder tuberculosis, or pro- ducts prepared from such milk, were consumed. The milk was taken for a longer or shorter time, in large quantities, by 151 children, 200 adults, and 9 persons whose age was not mentioned. These persons are divided by Weber according to the results of the investigations, into four groups, namely: 1.- Cases, in which an infection occurred of a bovine type. 2. Those in which a suspicion of an infection exists, but on account of insufficient bacteriological examinations has not yet been determined. 3. In affections in which the bacteriological examination relative to the suspicion of tuberculosis was negative, or in which the human type was found exclusively, and 4. Cases in which no affections whatsoever have been dem- onstrated up to the present time. In Group 1 an infection with the bovine type was demonstrated in two families, affecting one child in each. 21U TuberriiKisis. In both cases it was .possible to trace the consumption of milk containing the bacilli up to the nursing age. In one case it lasted for one and a half years, in the second case one year, and in the latter case the ndder affection had been recognized for three months during the period that the child had been using the milk. In both cases the respective cow was affected with a severe tuberculosis of the udder in all four quarters ; the milk had ])een consumed at all times mixed with the milk of a second cow, in the first case boiled or raw but in the second case only raw. The other members of the family remained well in spite of the consumption of this milk; in both instances only the youngest child became affected Mitli tuberculosis of the cervical glands. In the first case another child of four, and one of five years, Avas included in the family; in the second case children of the age of 3, 4, 7, 8, 9 and 12 participated in the consumption of the milk, all remaining normal. The tuberculosis of the cervical glands healed in the two youngest after aliscess formations, leaving several slightly en- larged small glands in the surrounding parts. One of the boys appears to be in the best of health, the other is somewhat behind in his development (at the age of 2 34 years he weighs 251bs.) ; in the last six weeks however his weight increased slightlv more than 1 lb. In the cases of the second group there exists suspicion of a bovine type of infection. In six children and one adult there are swellings of the cervi- cal Ijmiph glands and in four children and one adult a suspicion of abdominal tuberculosis is given. One child is affected with scrofula. In the four children the manifestations of disease re- trogressed, while in the adult it appears doubtful, according to Weber, whether the affection is of a tuberculous nature. Forty-one persons are included in Group 3, who consumed milk in a raw state from cows affected with tuberculosis of the udder. This was at times mixed with milk of other cows. A girl of 16 years of age and a boy four years old, who died of tuberculosis were included in this group. The producers of their infections were bacilli of the human type. A man and a woman who were affected A^^th pulmonary tuberculosis (human type), a boy with suppuration of the middle ear and cervical haupli glands (not tubercular) ; an 18-year old boy Avith rheumatism of the joints and valvular heart trouble, chronic diarrhea and pulmonary symp- toms (not tubercular) ; a woman with catarrh of the apex of the lungs (not tubercular) ; a woman with swelling of the glands, diarrhea, cough, night sweats and emaciation (inoculation of sputum without results), and a woman and a man with pulmonary SAnnptoms (not tubercular) were also in the total of forty-one. _ The cases in which a boy and a girl died from tuberculosis, are of especial importance. In spite of the prolonged consump- Table III. tr <- k At- ^ V? k from a rabereaiC'Bs adder. 1 X 1200. fy'it if-'i- Wi Danger from Boviiie Tuberculosis. ]_11 tion of raw milk from a tuberculous udder by tlie children who were already infected with the himian type of the disease, it was impossible to isolate from the tuberculous glands of the neck and mesentery any bacilli of the bovine type. Weber concludes from this that a body already infected with the human type of the dis- ease is resistant rather than susceptible towards an infection with the bovine type. The fourth group contains by far the greatest number of cases in which children and adults consumed raw milk from cows affected with tuberculosis of the udder, or milk products prepared from the same, and includes those cases in which no disturbances of the health resulted from such consumption. It was especially stated relative to the children that they all appeared thriving and healthy. Among these persons are included those who for a long period ingested especially great quantities of bovine tubercle ba- cilli ; thus a 13-montli old child has been brought up exclusively on raw and boiled milk from a cow affected with udder tuberculosis, and up to the present remains healthy. Other cases may be considered as presenting complete ex- periments with the necessary controls, since the persons who drank the milk remained healthy, whereas calves and hogs fed with the same milk developed severe ingestion tuberculosis. The ob- servations of such cases may be traced back incompletely for 3 or 4 years. A 25-year old waitress, and a 28-year old dairy hand drank mugfuls of freshly drawn tuberculous milk, frequently without any other milk being added without be- coming affected; the calf of the cow which produced the milk had to be slaughtered after four weeks, and showed tuberculosis of the mesenteric lymph glands, liver, lungs and kidneys, a severe ingestion tuberculosis. The milk of another highly affected tuberculous cow also suffering from udder tuberculosis, was mixed with the milk of two other cows, and was consumed frequently in a raw condition, by two adults and a 13-year child; a child l^/^ years of age was given the milk only in a boiled condition. The adults remained healthy; the calf from this cow had to be slaughtered after five weeks, and showed generalized tuberculosis. From the stable of a herdsman the milk of a cow affected with udder tuberculosis was mixed with the milk of three other cows, and the cream and butter prepared from this was consumed by four persons, aged 31 to 59 years, without producing any ill effects. The five hogs of the herdsman were found on postmortem to be tuberculous. Similar results were reported from the ingestion of milk from a tuberculous udder of a goat, which was consumed as raw and boiled milk by three adults and four chil- dren of ages from 5 to 16 years. The persons remained well while a hog became af- fected with ingestion tuberculosis. In two other cases the milk was consumed in a raw or unmixed state, as milk, buttermilk and butter. It was consumed by seven adults, in one case for a period of four months, in another case even longer. In spite of the fact that the family has been kept under observation for four years no disturbance in health can be detected. It is proven by the collected material of Weber that even though tremendous quantities of tuberculous material are con- sumed, still more favoring accessory conditions are necessary in order to produce an infection with the bovine type of tubercle bacilli. Of course it is not yet known, as indicated by Weber, how many of the children which show swelling of the cervical lymph glands and symptoms of suspected abdominal tuberculosis, are X^'2 Tuberculosis. affected with the bovine type of tul)erculosis, or how many of the persons who fail to show any distnr})ance of health may harbor one or more infected mesenteric glands ; likewise it is not known how many children with a latent form of the disease may through a special weakening, or nnder the influence of other infections, break down later with tuberculosis, possibly even with a fatal termination. Tlirough the compilation investigations we know only of the time (which extends over a period of 1-3-4 years in the individual cases), the opportunity and the immediate results of the infection, and not the further development of the same, but we do know that in two children a true bovine type of tuberculosis existed. Therefore, although a possibility of infection was present in a great number of persons, the infection has positivel}^ occurred up to the present only in two children in infancy. This constitutes proof that ''the danger which threatens man from the consumption of milk and milk products from cows affected with udder tubercu- losis is very slight when compared with the danger of man affected with open pulmonary tuberculosis to his fellow men." This conclusion of AYeber may be supported without further consideration. Nevertheless the danger still prevails, and al- though it is slight in comparison with the danger through infec- tion with the human type, it should he hj no means under-esti- mated; it should be considered that the danger of infection with human tuberculosis is amazingly great, and the opportunity of ingesting the bovine type of tubercle bacillus with milk is similarly great. Bovine Tuberculosis in Man in General. Although the attention of pathologists of all countries has been directed for the last ten years to infections of man with bovine tuberculosis, up to the present time there are collected only 117 cer- tain cases of bovine tuberculosis in children and 21 cases in adults (over 16 years of age). Of the 117 cases in grown children 105 are accurately de- scribed, and involve the following organs : 60 cases of abdominal tuberculosis 25 cases of tuberculosis of the cervical glands 4 cases of tuberculosis of the tonsils 7 cases were generalized 3 cases were localized in the bones and joints 6 cases represented lupus Two cases should also be included in which bovine bacilli were found in unchanged lymph glands. The 60 cases of abdominal tuberculosis are again divided into 34 severe cases in which the mesenteric l^miph glands, the intes- tines and the peritoneum showed changes. Thirty of these after generalization of the afl'ection, terminated in death. Bovine Tuberculosis in Man. 113 Twelve of the 60 patients had tuberculosis of the mesenteric glands, slight intestinal tuberculosis, and tuberculous meningitis. The 12 cases were severe fatal affections. In 14 cases the autopsy revealed tuberculosis of the mesen- teric lymph glands with the bovine tjY>e of bacilli, but this was found accidentally following other causes of death, as diphtheria, scarlet fever, measles, and pneumonia. In the 21 adults the bovine type of the disease was established three times in pulmonary tuberculosis ^vith expectorations, once in a primary abdominal tuberculosis and pulmonary tuberculosis, once in an infection of the buccal mucous membrane and cervical lymph glands, once each in tuberculosis of the knee joints, the kid- neys and the peritoneum, and finally the bacillus of bovine type was isolated from three cases of lupus, two cases of skin tuber- culosis, and five cases of tuberculosis verrucosa cutis in butchers. Besides these instances the bovine type of tubercle bacillus was isolated three times from the mesenteric glands of adults. In two cases of phthisis the bovine tubercle bacillus was found in association with the human type. Of the total of 138 cases, 56 were fatal, and 89 could be ex- plained with certainty or Avith the greatest probability as inges- tion tuberculosis. The other forms of tuberculosis, v^th the ex- ception of the skin tuberculosis of the butchers and of one milker, may also probably be traced to the same mode of infection. AYeber deduces from his findings that the danger of becoming infected with tubercle bacilli of cattle is great for the individual, but is only slight for the human race as a whole. Kossel reports in the German Medical Weekly relative to the number of cases of animal tuberculosis in man as compared with the human type of tuberculosis, and observed that in 1602 cases of human tuberculosis the bovine type appeared as the infective agent in 126 cases, the human type alone in 1464 cases, the human and bovine type in association nine times, and the a^^an type of tubercle bacillus three times. Therefore in about 8.6% of human tuberculosis, bacilli of animal origin were found, and in about S% of these they were of the bovine character. If however the most frequent form of tuberculosis of man is considered, namely pul- monary tuberculosis, then the bovine type can be demonstrated only in about .6% of the cases, whereas in the other forms of tuberculosis it may be found in 16% of the cases. Tuberculosis of bovine origin occurs most frequently in chil- dren in which tuberculosis of the cervical glands is caused in about 40% of the cases from infections with the bovine tAT)e, and tuber- culosis of the mensenteric glands may be traced to the same type in 40 to 50% of the cases. A portion of these affections, as has al- ready been mentioned, may terminate fatally. Among the fatal forms of tuberculosis in children 76% are caused by the human type and 24% by the bovine form. The meningitis type of the s 214 Tuberculosis. disease is brought on in "only about 11 7o of the cases by the bacil- lus of animal origin and in 89% by the human type of tlie organism. In tuberculosis of the bones and joints the iigures are 57© and 95% respectively. Galf ky, Rothe and Ungermann found in 400 bodies of children, 76 infections with tuberculosis, in which tliej^ succeeded in estab- lishing the variety of the bacillus. In one case they found the bovine type (1.32%), and among 171 other autopsies on children, of which 39 were tuberculous, two (5.1%) cases of bovine infection were observed. The results of tuberculous infections among children of the population of Berlin were therefore 95 to 96% of human origin, while only 4 to 5 % were of bovine origin, in spite of the fact that during infancy the danger of bovine infection is the greatest (Kossel). [According to figures compiled by Park of the New York City Board of Health, the frequency of bovine tuberculosis in man as collected by various investigators is as follows : In adults, 955 cases have been examined of which 940 showed human infection and 15 bovine infection. In children from five to sixteen years of age, out of 177 cases investigated, 131 were human infections and 46 bovine infections. Among children under five years old there were 368 cases of which 292 were found in- fected with the human type and 76 with the bovine type of tuber- culosis. Furthermore Park mentions the very suggestive results obtained from nine children under 6 years of age who were fed exclusively on cow's milk at the Foundlings' Hospital. Five of these children died of bovine infection and four of human infec- tion. On the other hand in the Babies' Hospital where the infants are nursed or fed on prescription milk, out of 63 children dying of tuberculosis, 59 proved to be human infection and 4 bovine infection. The figures taken from clinical work in England indicate that from 23 to 25% of the fatal cases of tuberculosis in children are due to bovine infections. Stiles of Edinburgh has presented in- teresting statistics to illustrate how bovine tulDcrculosis particular- ly affects young children. Of 67 consecutive tuberculous bone and joint cases, the bovine bacillus was present in 41, the human bacil- lus in 23, while in 3 cases both types were present. In those af- fected children under 12 months old, only the bovine bacillus was found. Of the 12 children between 1 and 2 years of age, 8 owed their disease to bovine infection, 2 to human infection and 2 to both bovine and human infection. There were 15 cases in 2 to 3 year old children, 11 of which were bovine, 3 human and 1 both infections. The 10 cases from the 3 to 4 year period were 6 bovine and 4 human infections, while the 4 to 5 year period included 3 cases of each type of infection. Stiles further reports on 72 cases of tuberculous cervical glands operated on at the Children's Hospi- Control of Bovine Tuberculosis. 115 tal in Edinburgh, in which the disease was due to the bovine bacil- lus in 65 cases, while in only 7 patients was the disease caused by the human bacillus. — Trans.] Conclusions. If we compile the results of this chapter the following conclu- sions may be established: Although tuberculosis of cattle is less dangerous for man than tuberculosis of man, the danger from the enormous spread of the disease in our herds, and especially among the dairy cows, should in no way be under-estimated. Theoretically the possibility of infection is afforded in all cases in which the ingestion of living tubercle bacilli with the milk takes place; from a practical stand- point however this possibility of infection comes into consideration only when the bacilli enter the individual in great quantities, and the resistance (of a local or general nature) of the body is not equal to this quantitative attack. This disposition, or these rela- tive conditions between the injurious agents and resistance, appear to be especially unfavorable in children ; therefore the requirement of the elimination from dairy herds of all tuberculous animals which pass tubercle bacilli with their milk, appears to follow as a matter of course. According to the experience at the tuberculosis eradication stations only those animals must be considered as eliminators of tubercle bacilli which are affected with open tuber- culosis, and expel the tubercle bacilli with their secretions and excretions, especially animals affected with tuberculosis of the udder, open pulmonary tuberculosis, tuberculosis of the uterus, intestinal tuberculosis, and furthermore animals with tuberculosis of the liver, kidneys, skin, eyes, and larynx. Measures Against the Danger. The elimination of animals passing tubercle bacilli should also be energetically encouraged on general economic grounds. For this work three methods may be followed : 1. Treatment of the disease and curative attempts. 2. The immunization of healthy herds. 3. Energetic sanitary police eradication measures, reduction of the possibilities of infection, and protection of young animals from- infection, together with favorable conditions for bringing up young stock as a preventive measure against their accidental infection, toward which we are powerless. The curative measures in affected animals may be left out of consideration as measures of control, since — excepting the uni- formly bad or only slightly favorable results — the methods of treatment for veterinary practice are too complicated, and are not practicable in consideration of the value of the animal. For the sake of completeness the experiments with iodipin should be mentioned here (Hauptmann). Creosote has also been employed. 1]() Tuberculosis. Of the specific remedies, tuberculin, tulase, tulase-lactin, tulon and tnberculase could be considered in the treatment of affected animals. These bacterial preparations, however, accord- ing to Romer and Arloing, are ineffective, since the results were negative. Better results Avere promised at the onset, from the specific innnunization methods, which aimed at a systematic preliminary treatment with slightly virulent strains, or with attenuated bovine tubercle bacilli, to increase artificially the resistance of the im- munized animals, that is, to protect them against a later accidental natural infection. As a matter of fact cattle immunized with tubercle bacilli prove for a time to be immune, or at least manifest a considerable resistance against a subsequent artificial infection with bovine tubercle bacilli, when compared with non-immunized control animals. For innnunization purposes there have been used : 1. Dry tubercle bacilli of the human type (bovo-vaccine. Von Behring's method). The injection is made into the blood circula- tion and is repeated. Animals treated in tliis way after 3 to 4 months, resist an intravenous injection of bovine tubercle bacilli, to which untreated animals invariably succumb. This increased resistance however lasts only a short time. According to the in- vestigations of Rossignol and Yallee and Hutyra it diminishes to- M'ards the end of a year, and after another six months it practically disappears. Against the slight practical success of this method the disagreeable fact should be considered that the injected tubercle bacilli of luan are retained alive in the body of the cattle for years, and may even produce in the udder local tuberculous processes, from which the bacteria of human tuberculosis may enter into the milk (Lignieres, Weber and Titze). Titze found that following an intravenous injection of human tubercle bacilli, they were eliminated from the udder even 16 months after the injection. In this regard the various individuals manifest an entirely different behavior. In three other cases bacteria were eliminated after a single injection, from the fourth week up to the 144th day. In a second cow which received an injection of tubercle bacilli of human and bovine type the elimination commenced after the third injection, and in a third cow as early as 24 hours after the injection. All three animals eliminated the bacilli from only one quarter, without this showing tuberculous changes. Bongert found in 186 bovo-vaecinated cattle, 36 which passed tubercle bacilli with their milk. The protective vaccination of Von Behring therefore is not only of little practical value, but grave dangers must be considered in connection with it, since the vaccinated animal may eliminate tubercle bacilli with the milk for 21/0 years and longer. Koch and Schiitz, Neufeld and Miessner recommended for the immunization of cattle a single injection of 0.01 gm. tubercle bacilli in suspension, which vaccine they termed ''tauruman." The above statement applies equally for tauruman as it does for bovo-vaccine. Similar results to the immunizing value of the in- travenous injections, according to Baumgarten, Lignieres and Tuberculosis Vaccination. 117 Klimmer may be derived from the single subcutaneous admin- istration of human tubercle bacilli. According to Lignieres even in such cases the bacteria may remain alive for as long as two years. According to Von Behring, Calmette and Gnerin, Eoux and Vallee, cattle may become immunized by feeding with slight quantities of bacilli from tuberculosis of the horse (or bovine tuberculosis). Arloing attempted to immunize with homogenized cultures of strains which had been cultivated in 6% glycerine bouillon (human type and bovine type). Better results were obtained from the intravenous than from the subcutaneous applications and this again proved superior to administration per os. Klimmer eliminated the danger of the vaccination for man by heating the human tubercle bacilli to 52-53 deg. C, or by rendering them avirulent by continuous passages through the crested newt. Both these vaccines are no longer pathogenic for guinea pigs, and they cannot regain their virulence by means of passages through animals. The results of immunizations are supposed to be favora- ble (Klimmer on 10,000 cattle), especially if the vaccination is carried out together with general protective measures, such as raising calves on milk free of tuberculosis, and the elimination of animals with open tuberculosis. Glockner even believes that vac- cination has a favorable action on the curing of animals which were already affected with bovine tuberculosis prior to the vaccination, whereas Eber attributes the improvement of the vaccinated herds to the simultaneously executed prophylactic and hygienic meas- ures. Friedmann aimed to produce immunization with his tuber- cle bacillus from cold blooded animals (turtle). Other authors however failed in producing an effective immunization with such strains (Libbertz and Ruppel, Weber and Titze, Orth). Heymanns attempted to immunize cattle by the introduction under the skin of cattle of a closed sack of vegetable fiber, contain- ing living tubercle bacilli (human or bovine in origin). The sup- position is that these vegetable sacks will confine the bacilli at the seat of inoculation, and that the treated animal will be immunized by protective metabolic products, that continuously form in small quantities within the sack and pass outward from it into the animal's system generally, by an osmotic process. The vaccination, which is carried out with the aid of a tro- car to insert the capsule under the skin of the back, must be re- peated annually, since the bacilli may die. Ueymann's method has been successfully used by its discov- erer on more than 20,000 cattle, and the percentage of reactors to the tuberculin test diminished from 45 to 21 (18 herds with 188 animals). Animals which have formerly reacted may appear free at the subsequent test. Good results were obtained by Vallee from passive immuniza- tion. He inoculated young cattle with 100 to 200 c. c. of a protec- tive serum, which he obtained from a horse treated with slightly virulent strains from horses, and then with strains from men. ][28 Tuberculosis. With this method he succeeded in rendering- the animals resistant to artificial infection with bovine tnbercle l)acilli. Since immunization methods have not offered nniformly satisfactory results, and since they must be prohibited on the ground of milk hy.<>ieno, therefore results may be expected only from proved sanitary police measures. Tlie methods which must be followed in the eradication of bovine tul)erculosis are: 1. Diminution or elimination of the sources of infection, (a) By removal of the animals passing bacilli, (b) By separation of healthy and suspected or diseased animals, (c) By l)ringing np tuberculosis-free yonng animals. 2. Improvement of the general methods in the care of young stock, l)y introducing conditions which approach the natural mode of living: (a) Proper care and feeding in well ventilated and lighted stal)les, (b) Dividing tlie pastures so- that the animals may be sepa- rated (according to whether they are suspected or healthy) and kept in accordance with their age and with the nse for which they are later intended. Measures for eradication must be applied in accordance with the rules here outlined. The most effective method of eradication was worked out by Bang", and consists in the elimination of clinically recognizable dis- eased animals, the separation of reacting animals, and the bringing up of calves on milk free of tubercle bacilli. The remarkable value of Bang's methods has been proven fully in practice by the results obtained since 1892. It is important for the results to separate completely the animals which fail to react to tuberculin, that is the healthy cattle, from those which harbor the disease and which react to the tuber- culin test. This should be done in such a way that the healthy animals are placed in a freshly disinfected stable or in a portion of a stable provided with a separate entrance, and separated with a board wall, from that part in which the reacting cattle are housed. The attendants of the healthy herd should not come in contact with those of the diseased herd. Animals of the reacting group which after a time become affected so that they may be clinically recog- nized, should be slaughtered as soon as possible. Young stock which react should not be permitted to breed, or at least should he immediately placed with the reacting group, providing their breeding value is such that this procedure is deemed advisalile. All reacting animals under six months of age should be slaughtered, that is they should be utilized for meat. Young stock and work oxen should also l)e included in the *& Methods of Eradication. 119 segregation, and the liealthy ones must be kept from contact witli reacting animals. Of the calves which are born after the separation, those from non-reacting cows remain with their mothers; the calves from reacting cows, after receiving the colostrum from their mother on the first day after birth, should be placed in the stable of healthy animals, and should be fed with the milk of healthy cows or should be brought up on sterilized milk, or they may be allowed to suck from healthy nurse cows. As soon as possible after weaning the calves should also be subjected to the tuberculin test, and those giv- ing a reaction should be immediately removed. From 1 to 2% of these calves react. It is proper to place the healthy calves in a stable of healthy young stock, and they may pasture with them, or if this is not pos- sible they should be placed with the older non-reacting group of animals. Before the first breeding the heifers again should be subjected to the tuberculin test, in order to place them in the prop- er group of cows. The tuberculin test is annually repeated in the healthy herd, in order to eliminate the animals which in the course of the year have had a possible opportunity of becoming affected with tuberculosis. Newly purchased animals are clinically examined and tested with tuberculin, and are added to the healthy herd only when the results are entirely satisfactory. The male animals which are to be used for breeding purposes should not react to the tuberculin test. Under unavoidable cir- cumstances, a reacting bull may be reserved for breeding pur- poses but only under special precautionary measures. The results of Bang's eradication method, if carefully carried out, are remarkably satisfactory. It has been adopted to the greatest extent in Denmark, Sweden and Norway, and it has also been successfully carried out in Hun- gary and Finland. The report of Regner, in 1911, atfords a good review of the results of Bang's method, and in it are described the results of the governmental eradication of tuberculosis in Sweden. Regner di- vides the eradication work into an offensive one in herds in which the disease prevails, and into a defensive procedure whose purpose is the prevention of the introduction of diseased animals into herds free of tuberculosis. Of the groups into which Regner separates the herds and the animals, the first group includes those which originally (on the first tuberculin test which in some instances was applied years previously) were found tuberculous. At that time 16,852 animals had been tested with a percentage of 30 . 2 reactors. In 1908, 18,719 animals in 457 herds proved to be entirely free from tuberculosis. The herds of the second group, which proved to be tuberculous ][0Q Tuberculosis. at the time of the inaiigiiratioii of the method and which continued to contain reacting animals, inchided 375 herds of 21,899 animals, with 41.57p of reactors. At the end of 1908 the nmiiber of cattle had increased to 26,181, of which only 1,496, or 5.7% reacted. The results were not so pronounced when the reacting animals were retained with the healthy animals, when cattle without the necessary precautionary measures were placed in herds free of tuberculosis, when animals which had not reacted in the old herd were removed into the free herd without being previously tested, or when an opportunity was given for the transmission of the in- fection by a reacting bull causing the infection in the herd to ap- pear to be renewed. Also in cases when the milk used for the feed- ing of calves was not free from tubercle bacilli, the results were unsatisfactory. In the interest of systematic eradication, it is necessary, espe- cially at the commencement of the eradication work, to suliject the animals to the tul)erculin test quite frequently, with short intervals. As a third group Regner included 436 herds containing 7,835 animals at the beginning of the work and 9,114 cattle in 1908, which at the first examination, and again in 1908 were free from reacting animals. The fourth group contains the herds which originally were free from tuberculosis but were not so at the test in 1908. The 98 herds included at first 2,526 and in 1908, 3,720 animals, of which 265 or 7.1% reacted. Eegner concludes from his tabulations : that on the first tuber- culin test in 1366 herds, out of 49,112 animals tested, 14,175 or 28.9% reacted; that in 1909 the same herds contained 57,734 ani- mals, of which 1761, or 3.1% reacted; that Bang's method is the strongest factor in the general promotion of breeding, and of stable and milk hygiene. In other countries the results were similarly favorable. Bang succeeded in Denmark, from 1893 to 1908, in gradually reducing the percentage of reacting animals from 40 to 8 . 5. Malm in Norway from 1896 to 1903 reduced the disease from 8.4 to 4.9%). Hojer in Finland in 1894 to 1900 caused the infection to drop from 24 to 10.1%. Hutyra reports on experiments carried out on the government farm of Mezohegyes. In this herd the first tuberculin test in 1 898 showed 44.8% of reactors out of 329 cows or 26.6% of the entire herd (647 animals), whereas in the fall of 1903 out of 502 cows only 2.8%, and out of the total of 1,132 animals only 1.8% reacted to the tuberculin test. The herd had been increased in this period by 75%, without purchasing additions to it, and the percentage of reactions had dropped 88%. The stringent measures of Bang have been somewhat modi- fied in certain cases for economic reasons, or when the strict execu- tion of Bang's method has presented peculiar difficulties. On the Ostertag's Method. 121 other hand the requirements have been accentuated in cases where favorable considerations prevailed. Thus for instance in a herd in which only a few animals react it would be advisable to dispose of them without further consideration, and after a thorough disinfec- tion of the stable the defensive work against tuberculosis may be instituted, through the introduction of only non-reacting cattle, and by the disposing of all animals which prove tuberculous on the following tuberculin tests. The Siedamg-rotzky-Ostertag method consists of immediate disposition of all animals with open tuberculosis (by this means the animals eliminating tubercle bacilli are excluded), and in bringing up the calves free of tuberculosis by feeding them with pasteurized milk or with milk from healthy cows. The calves are subjected to the tuberculin test after they are weaned, and the re- acting animals are not bred. The herds which are included in this method of eradication are subjected semi-annually to a clinical examination, and the clinically suspected animals are removed and disposed of. Further than this, the mixed milk of the herd, as well as the suspicious secretions and excretions are examined bacteriologically. The results of the Ostertag eradication method of course can not be compared v/ith that of Bang. Since there are retained in the herd all tuberculous animals which show no clinical form of tuberculosis, or in which there is a suspicion of open tuberculosis but whose secretions and excretions fail to reveal the presence of tubercle bacilli. Therefore a constant danger of infection for the animals free of the disease prevails, as tuberculosis may at any time develop into an open form. But since it is required that the calves should be brought up free of tuberculosis, and that the elim- inators of tubercle bacilli should be determined by periodical clin- ical examinations as well as by the testing of the entire mixed milk of the herd and the individual secretions and excretions of sus- pected animals, Ostertag has obtained relatively very good results, where his requirements have been conscientiously carried out. This method has an advantage in that the stock owners who offer great objections to radical methods of eradication on ac- count of the immediate economic losses which they entail, are will- ing to work intelligently and with pleasure with a system of eradi- cation such as is offered by Ostertag's method. This assertion is best proven by the tabulation of Eautmann, which shows the in- creasing popularity of this method. The method was voluntarily adopted in the fol- lowing cases: 1903-1904, 1,457 animals; 1904-1905, 1,372; 1905-1906, 5,333; 1906-1907, 5,395; 1907-1908, 5.193; 1908-1909, 8,839; 1909-1910, 18,822; and 1910-1911, 19,828 animals. The following data illustrate the results obtained with the method : Open tuberculosis was present in the province of: East Prussia in 1900 in 2.7 % out of 10900 examinations East Prussia in 1904 in 1.3 % out of 17500 examinations Pommerania ; in 1902 in 2.93% out of 8808 examinations Pommerania in 1906 in 0.6 % out of 22356 examinations Brandenburg in 1903 in 3.46% out of 5200 examinations ] 22 Tuberculosis. Braiiilojibiiry; in 1907 in 1.5 % out of 5810 examinations Schloswifj-IIolstein in 1903 in 2.8 % out of 2435 examinations Schleswig-Holstein in 1905-6 in 1.93% out of 11000 examinations Saxony in 1903 in 3.6 % out of 1457 examinations Saxony in 1906-7 in 2.41% out of 5395 examinations In these statistics it should be eonsi. o Cd r^ iq 181 IX) t^ CM in CD CD o CO o CD CM Oi GO CM (M O CO irt) CD CD CO O o CO CM P CO CD CO (M O . bfj ;:3 be o o ^ CO CM CM CO CO (M ^ GO GO t^ t— GO CO vd GO CO CO CD CO CM CD Qa2a2P^QPHOpqOc/2a2PHpQ 182 Defects of Milk. At the same time it appears as though the spoiling- of milk, for instance by souring, is less inHnenced by the temperature, Avhieh of course may be of importance, than by the atmospheric pressure. It could hardly be attributed to an accident that, ex- cept at harvest time when the milking is sometimes hurriedly done, the number of samples spoiled by souring were almost in recipro- cal relation to the measured average value of the atmospherici pressure for the month. Likewise in several months a certain parallel exists between the occurrence of dirty milk and souring, so that the dirt is present in largest amounts during August, September, October and Novem])er. Months in which milk contains a great deal of dirt appear also to favor the requirements for the development of a putrid taste. (Height in June, August and October, harvest time.) Dur- ing this period the milk is not aired and cooled, so it "suffocates." The cans are not cleaned, and all dairy work is slighted. Direct contamination with cow nianine appears to be of less importance in the development of an animal llavor, than polhition with bacteria from the skin of the cow, which may contaminate the animal while in pasture. These views are strongly siipi)orteil by the experiments of Wolf and Weigniann, who proved the identity of the bacterial ilora of the defective milk with the bacteria which were cultivated from the ]iastiire plants, and by the experiments in which the authors succeeded in reproducing artificially these defects by nsing special bacteria. This view is also supported by the observations of the author. A milk dealer complained about the bad taste of milk in a certain delivery. It was noticed that only the evening milk of the farm, and not the morning milk possessed the defect. Before the evening milking the animals were kept in a pasture during the day. It was remarked from the beginning that the morning milk did not have the taste, which was the more suprising since the animals by standing in the stable during the night must have affected the purity of the stable air. Nevertheless the evening milk which was obtained in the stable after a sufficient airing and cleaning, possessed the objectionable taste. Of course the time could have played a part since both the morning and evening milk were delivered at the same time, the evening milk being allowed to stand all niaht at a temperature of 12 deg. C. The milk was kept in a milk room next to the stable. The conditions, however, were not changed by removing the milk immediately after milking, to a well-ventilated room, cooled by ice. The passing of the odoriferous substances into the milk directly from the food could be excluded since the substances could then have been demonstrated in the morning milk as well, and therefore the only explanation which remained was that while lying down the abdomens of the animals became contaminated with the bacteria of pasture plants (meadow grass and clover). These bacteria contaminated the evening milk during milking in the stable, whereas the morning milk was principally contaminated with bacteria from the bedding. All other factors could be given about equal consideration. That the age of the milk did not play a part was proven by the fact that the morning milk in spite of longer keeping during both cold and warm weather in exposed or covered vessels, had never been affected by the disagreeable taste. It is almost impossible at the present time to establish definite relations between defects in milk and contamination of milk with bacteria, since the propagation of the bacteria causing the defects may be influenced by the most varied factors. It should be especially emphasized that bacteria of one and the same species may under certain conditions produce different defects in milk, depending on the accompanying conditions, as for instance whether they are associated with one or several other species of bacteria. Coagulation Types. 183 According to Wolff and Weigmann the Bacterium fluorescens possesses the characteristic of producing by itself an ester-like odor, while together with the Bacterium mycoides and the Strep- tococcus lacticus it produces a disagreeable aroma, and finally with the Bacterium megatherium, B. mycoides, and lactic acid bacilli it produces a cheesy odor. This of course renders the study of milk defects difficult, since a bacterium cultivated in pure culture may show an entirey different action than when present in milk in a mixed culture, and mixed culture experiments with the entire flora would become necessary. Types of Coagulation. The decomposition and fermentation microorganisms, which develop in milk, are utilized in the examination of milk that is in- tended for the manufacture of cheese. A fermentation test is made from each delivery of milk, and after a certain time each sample is tested for odor, taste, and in regard to its appearance and visible changes. According to Jensen the fermentation may be distinguished as : 1. A fluid type, 2. A jelly type, 3. A gaseous type, 4. A whey type, 5. A cheesy type. It should be emphasized that milk samples rich in bacteria usually produce a good jellylike type, whereas in milk samples containing few bacteria, whey fermentation frequently occurs. The jelly type results in the profuse presence of lactic acid formers, which distend and tear the coagulum by the action of aerogenes varieties and cheese bacteria, whose gas production fre- quently forces the coagulum upwards. The milk becomes whey when true saccharomyces varieties form gas at the moment of coagulation. At the same time sub-types may be distinguished, such as porous, granular and flaky. The cheesy fermentation type develops in the presence of an increased number of rennet- producing bacteria. These fermentation tests of milk are important to ascertain if it is in satisfactory condition for cheese production. For the de- termination of its fitness for drinking purposes, however, these tests are of little importance, since the questions relative to the value which these bacteria possess in the nutrition of man, have never been satisfactorily answered. Bacterial Reductase, Bacterial Catalase and Lactic Acid Production. Among the characteristics of milk bacteria, which are of especial interest are those which are utilized in the examination of milk, and which may have a disturbing effect in experiments 184 Reductase, Catalase, Etc. eondncted for tlie demonstration of ori,i^-inal ferments because of the reactions wliicli they cause. One characteristic is the reduc- ing property of some bacteria and their ability to split up HX).. into water and molecular oxygen, corresponding to the action' of catalase. The reducing action of bacteria as indicate.] bv the presence of re.hu-tase lias been observed for a long time. Heln.holtz in 1843 proved that putrefactive changes nhu-h conhl not be demonstrated by changes of odor could be proved by discoloration ot litmus coloring matter. Subsequently this reducing action was confirmed by many authors .0 be t lie property of various anaerobic and aerobic organisms. Thus according to Gayon and Dupetit the anaerobes are capable of forming ammonia from nitrates while the Bacillus produ/io.sius, B. anthracis, Spir. finkler and Staph, ilocuccns citreus torm nitrites out of nitrates. Others again reduce sulphur to H.S (through "Hvdro- genase ). " ^ -^ As an agent for demonstrating the reductase processes some authors, for instance ^plna, Cahen and Wolff, use coloring substances which change into leuco-compounds, as a result of the reduction, but from renewed contact with the air they become re- oxydized, as for instance tincture of litmus, thionin, methylene blue, indigo" blue, neutral red, etc. Others again iise metallic salts to render the reduction directly visible (Scheur- len and Jvlett, Gosio), for instance selenite and tellurite, whose sodium and potassium compounds confer upon the colonies a brick-red or grayish-black tinge, by the reduction or indirectly, the transpiring reductive action is shown through secondary reactions for instance the formation of nitrites from nitrates, through the addition of iodine starch paste which becomes decolorized by the nitric acid. Methylene blue is used at the present time most extensively for the reductase test; that is, the solution recommended bv Schardinger consisting of 5 parts of concentrated alcoholic methy- lene blue solution to 195 parts of water is best adapted for the examination of milk. The reducing qualities of various bacteria towards methylene blue vary. Thus Jensen established the reduction qualities" of a series of milk bacteria, and proved that varieties of colon, staphy- lococci, sarcina, and mould fungi, reduce rapidly, whereas acid streptococci do not decolorize the solution. The findings of Koning, who used cultures 24 hours old in his experiments, were the same. Arranged according to length of time, reductions take place as follows: Bacillus fiuorescens nonliquefaciens, in g min Bac. acidi lacUci Hueppe, in \\ jo ^:^^ Bac. prodigiosus, in 10-15 min' Bac. piorescens liquefaciens, in 13 n,jjj' Proteus ,opfii, in. :'.::: .::::['.: 15 min! Bac. coll communis, m 27 j^-|- Bac. subtilis, in on ^iJ ■nf , . ' . oO mm. Mesentericus, m «a ^• ilk bacteria I, m on Tn,-,, r,i , . r, \ . .-, ou mm. btreptococci of lactic acid, Oidium lactis and 2 stable atmospheric bacteria, not in 90 j^^j^, Schardinger in 1902 stated that suspensions of the Bacillus acidi laevolactici decolorize m 3 minutes, the Bacillus pa-soformans in 3 minutes, the Bacillus lactis pituitosi m 80 minutes, the Bacillus coli in 1.5 to 20 minutes, etc. The ability to reduce methylene blue has also been found in anthrax and tubercle bacilli. In the experiments it was proved that although not all bacteria are capable of reducing methylene blue, the power of reduction in some is very strong, while in o^^hers it IS diminished and in still others it is practically nil. Reduction properties appear to be characteristic of the living Reducing Properties of Milk. 185 bacterial cell, which do not pass into the filtered fluid (Schar- dinger, Spina, Cahen). From the above mentioned facts it is evident that milk which contains numerous bacteria has a strong reducing property. Through the works of Smidt, Mtiller, and Schardinger it has been proved that as a rule the richer the milk is in bacteria the earlier the reduction of the aqueous methylene blue solution at 37 deg. will occur. Milk drawn under sterile conditions fails to reduce the methylene blue solution even after days (Rullmann). Miiller proved that freshly drawn and cleanly handled market milk re- quires 10, 12 or more hours for reduction (mixing 10 parts to 1 part of methylene blue solution), whereas fresh market milk during cold weather requires 6 to 9, and in warm weather only 1 to 2 hours for the decolorization. At the stage when bacteria begin to multi- ply, which is at the end of the incubation period, the time required for reduction amounts to from 1 to 2 hours. If sour milk or cow manure was added to fresh milk the time of reduction was hastened. He therefore proved that all factors which favorably influence bacterial growth hasten the reduction. In the author's first investigation he found that 10 e. c. of milk with about 44,000 bacteria per c. e. failed to reduce one c. c. of methylene blue solution in six hours. With about 200,000 bacteria reduction took place in 4 to 6 hrs. With about 500,000 bacteria reduction took place in 3.5 hrs. With about 1,600,000 bacteria reduction took place in 2 hrs. With about 6,000,000 bacteria reduction took place in. 70 min. With about 350,000,000 bacteria reduction took place in 50 min. With about 800,000,000 bacteria reduction took place in 15 min. Similar results were obtained by Jensen as follows: With about 264,000,000 bacteria reduction took place in 1 min. With about 80,000,000 bacteria reduction took place in 3 to 5 min. With about 50,000,000 bacteria reduction took place in 10 min. With about 7,000,000 to 11,000,000 bacteria reduction took place in 40 to 60 min. With about 3,000,000 bacteria reduction took place in 2% hrs. With about 1,600,000 bacteria reduction took place in .... 7% hrs. With about 1,000,000 bacteria reduction took place in 6% hrs. With about 126,000 bacteria reduction took place in 91/^ hrs. _ Since the degree of acidity increases with the growth of bac- teria there exists a certain connection between the degree of acidity of the milk and the rapidity of reduction, and since the degree of acidity increases rapidly after incubation, a rapid reduction would be expected to follow a rapid increase in the degree of acidity. This is also proved by Jensen 's experiments. Milk which reduced in one minute had after 12 hours, at 25 deg. C, a degree of acidity of 36. Milk which reduced in — 5 min. after 12 hrs. at 25 deg. had an acidity of 19 8 min. after 12 hrs. at 25 deg. had an acidity of 20 6 min. after 12 hrs. at 25 deg. had an acidity of 35 10 min. after 12 hrs. at 25 deg. had an acidity of 22 8 min. after 12 hrs. at 25 deg. had an acidity of 18 7 min. after 12 hrs. at 25 deg. had an acidity of 28 1 hr. after 12 hrs. at 25 deg. had an acidity of 15 % hr. after 12 hrs. at 25 deg. had an acidity of 25.5 1% hr. after 12 hrs. at 25 deg. had an acidity of 11.5 186 Reductase, Catalase, Etc. 21/4 hr. after 12 hrs. at 25 deg had an aeidity of 15 S'-Yi hr. after 12 hrs. at 25 de^r. had an acidity of 9 6Vi hr. after 12 hrs. at 25 deg. had an acidity of 9 7 hr. after 12 hrs. at 25 deg'. had an acidity of 10.5 Gl-t hr. after 12 hrs. at 25 dej^'. had an acidity of S 7^2 hr. after 12 hrs. at 25 deji'. had an acidity of 8 12i/i hr. after 12 hrs. at 25 dco-. had an acidity of 7 S\-2 hr. after 12 hrs. at 25 deg. had an acidity of 7.5 The findings of the anthor were very ninch the same as those of Jensen. ]\rilk Avhicli failed to reduce in 20 hours had after 24 hours at 20 deg., from 7.4 to 10 degrees of acidity. The following- table shows the results of the technique em- ployed in testing- milk, where the reduction number is understood to mean the number of drops of methylene blue solution which in a given time was completely reduced by 5 c. c. of milk: Degree of acidity After 24 hrs. Time required at delivery at 20 deg. for reduction Eeduetion number 7.0 7.4 20 hrs. 6.2 8.6 20 hrs. 6 10 20 hrs. 6 9 20 hrs. 4 7 10 20 hrs. 6 24 4 hrs. 2 6.4 26.5 8 hrs. 10 6.5 20 8 hrs. 6 6.2 24 8 hrs. 8 6.2 27 8 hrs. 6 6.8 23 8 hrs. 4 6 14 8 hrs. 4 7.8 30 6 hrs, 4 6.5 28 2 hrs. 2 7.2. 32 Ihr. 2 6 34 Ihr. 2 6.2 38 Ihr. 10 8 40 5 hrs. 10 10.5 26.4 0.5 hrs. 10 6 30 6 hrs. 2 These numbers were obtained from a great number of sam- ples during work at the milk control station, without any selec- tion. They show that milk which sours rapidly, and is therefore at the end of the incubation period, also reduces rapidly; there exists, however, no absolute constancy in the parallelism, neither with the values of acidity in milk after twelve to twenty-four hours, nor with the values in samples of fresh milk. After thorough souring the reduction power of the milk again diminishes for a time. This may be due to the fact that the acid reaction inhilnts the reduction power — as a matter of fact the rapidity of reduction is again considerably increased by the addi- tion of sodium carbonate or bicarbonate — and also because a non- reducing organism, the acid streptococcus, outgrows the other bacteria. The addition of an alkaline solution brings about acceleration of the reaction only in sour milk, while in milk with low bacterial count the reaction is retarded, but this may be overcome when through acid formation neutralization has taken place. Bacterial Catalase. 187 Antiseptics, such as boracic acid, salicylic acid and formalde- hyde, inhibit or destroy the reduction power of bacteria; the same result is obtained by heating, which destroys the life of the vegetating bacterial cells. Milk which has been heated for 10 to 30 minutes at 80 to 100 deg. C. shows only the slightest reduction power, _which_ increases again only after the recurrence of bacterial multiplication. It should be emphasized that milk, in spite of being spoiled to a marked degree, may have a slow reducing power, as for instance soapy nnlk, provided this condition is not associated with extensive bacterial contamination with other species of bacteria. Although the bacillus of soapy milk reduces very rapidly, soapy milk in itself is only capable of bringing on this reaction to a very slight degree, which probably is proof that defective flavors may result even when only a very slight bacterial growth has taken place, although the bacterial action is of tremendous importance. For the completeness of this chapter it should be mentioned that milk very rich in bacteria, which has been sterilized by heat, reduces also the formalin methylene blue solution as a result of the original bodies in milk, a property which has nothing to do with the Schardinger reaction. The formalin methylene blue reducing principle in market milk is also a pre-formed substance, which occurs in milk drawn under sterile conditions (original ferments). Bacterial Catalase. Similar to the power possessed by body cells and body juices, bacteria have the ability of splitting gaseous oxygen from hydrogen peroxide solutions. This property may be observed in many bac- teria, but it should be mentioned that not all species of bacteria possess it, and that certain bacteria have a specific power in this direction. Koning and Jensen made confirmatory statements to this effect, having found that the acid streptococci of milk do not split H2O2. The author's experiments confirm this observation. Jensen made an especially interesting observation, namely ,_ that the bac- terial flora present in milk during the incubation period of souring usually possess strong catalytic properties. The following data are taken from a work of Koning, arranged according to the catalase figures : Species of Bacteria Catalase test Reductase test B. prodigiosus ^^ ^'^ minutes B. proteus eopfii 57 15 minutes Milk bacterium 1 55 80 minutes B. fluorescens liquefaciens 53 13 minutes B. eoli communis 39 17 minutes B. lad. acid. Hueppe 32 12 minutes Stable air bacteria II 31 90 minutes B. meseniericus 30 60 minutes B. flxiorescens nonliquef. 29 15 minutes 188 Reductase; Catalase, Etc. Stable air bacteria T 28 90 minutes B. suhtilis 17 40 minutes Milk bacteria IJ 15 90 minutes B. miicoidcs 11 90 minutes Oidiurn lacU.^ 11 90 minutes Sir. mastitis lungus 90 minutes From those figures it may be seen that frequently with a high catalase number a very rapid reduction time may be present. Jensen found similar conditions in his investigations; he, however, expresses himself as believing that a parallelism of ))oth factors does not prevail. Arranged according to catalase values expressed in figures, giving the number of c. c.'s of oxygen formed, the relation between catalase and the time of reduction is as follows: Catalase Eeductase B. protexis vulgaris 27 c. e. 7 minutes B. protetis zopfii 27 e. c. 5 minutes B. prodigiosus 27 c. e. 7 minutes Microc candic 27 c. c. 4 minutes Microc. A 27 c. c. 3 minutes B. coli 18 e. e. 5 minutes B. aerogenes 9 e. c. 10 minutes B. mycnides 7 c. e. 12 minutes B. dentrificans 1 C. C. 10 minutes With other bacteria, for instance, butyric acid bacteria, there appears to be no relation between the reduction power and the development of oxygen, whereas with certain lactic acid producers, for instance, the streptococci and cheese bacilli, the inability to develop oxygen coincides with the long time required for reduction. In unspoiled milk during the incubation stage of souring and at the beginning of souring at the end of this incubation stage, the bacterial catalase will always have to be considered, but in general the bacterial action in slowly reducing milk is very slight. If in the latter instance high catalase values are obtained then usually the catalase originally present in the milk is responsible for it. Koning further showed that catalase increases with the age of milk, and with a rapid angle of incidence. The line of incidence in fresh milk is at first only slightly bent, later more or less so, whereas old milk uniformly shows a rising line. Spindler's recent experiments confirm this statement. From the investigations of Spindler, however, it may be observed that during the time when milk is fresh enough for drinking purposes the fluctuations are only very slight and the catala?e value obtained is always greatly dependent on the original catalase value of freshly drawn milk. Faitelowitz indicates that catalase multiplies many fold after keeping fresh milk at room temperature for 24 to 30 hours. Through heating to 70 deg. C. the ''bacterial catalase" is destroyed, or at least the bacteria are attenuated in their action to such an extent that the oxygen-splitting property becomes almost nil. Chick has already ascertained that this inactivation of the bacterial catalase may be abrogated in a certain time by inoculation of the heated milk with raw milk and Koning states that old pasteurized milk, or milk freshly pasteurized with insufficient heat, splits the H2O2. The catalase test is therefore recommended by Kniisel for the examination of pasteurized milk as to its suitability for drinking purposes. Acidity of Milk. H It is to be regretted that the bacterial catalase cannot be separated from the original catalase, so that it would be possible to draw definite conclusions from the catalase findings of market milk, as to whether the catalase quantities which are demonstrated were present in the freshly drawn milk or whether they have been subsequently formed by bacterial growth. Wolf claims that milk Avhich reduces slowly and shows a strong catalytic property by the formation of large quantities of oxygen should be suspected of containing secretions from animals with affected udders. It would be impossible to draw conclusions based on this statement in those cases where rapid reduction occurs coincidently with strong catalytic action. Degree of Acidity. In discussing the original properties of milk it was mentioned that casein, acid salts of milk, carbonic acid, etc., give to milk an acid reaction to phenolphthalein. Even immediately after milking, in order to produce neutral- ization of the milk against phenolphthalein, several c. c. of sodium hydrate are required. The number of cubic centimeters of a normal Na OH dilution which are needed to neutralize a certain quantity of milk are known as degrees of acidity. The number obtained varies, depending on the method and dilution employed. Thus Soxhlet-Henkel, for instance, employed 100 c. e. of milk and 14 normal Na OH and obtained an average value of about 6 to 7 degrees of acidity, Jensen, who works with tV normal Na OH, uses on an average 18 to 19 c. c. Thorner dilutes 10 c. c. of milk with 30 c. c. of water and titrates with to normal Na OH. The degrees of acidity, as determined by Dornic, are higher than those of Soxhlet-Henkel : He uses 10 c. c. of milk and alkali which contains 4.445 gm. Na OH to 1000 H^O. tV c. e. of alkali, according to Dornic, is equal to a degree of acidity. Schrott-Fichtl and Dornic suggested as an advantage the drop- ping of the ''scale of degree of acidity" and employing an alkali, 1 c, c. of which would correspond to 0.01 gm. of lactic acid, or to figure the degree of acidit}^ on the basis of lactic acid. Then 1 c. c. of TO alkali would correspond to 0.009 gm. of lactic acid and 1 c. c. of 14 normal Na OH=22.5 gm. Of course, it should be remembered that the neutralization of the alkali does not correspond entirely to the amount of lactic acid present but depends also on other factors, for instance, on the proportion of acid phosphates, carbonic acid and casein. Only the increase in acidity which is obtained by a compara- tive testing of fresh milk and an older sample of the same milk, should therefore be considered as lactic acid, since Henkel proved that free lactic acid is not present in freshly drawn milk. 190 Reductase, Catalase, Etc. The degree of acidity of milk depends on the lactation period. Colostrum, milk of animals with affected ndders, and milk from freshlj'- milking- cows have an abnormally high acidity, while milk from animals in the last stages of lactation, and sometimes milk from affected ndders, may be lower than normal. Besides these factors the degree of acidity of milk is also influenced by the growth of bacteria, the species of bacteria, and therefore by all factors which have an influence on the bacterial gi'owth, such as cleanliness in milking, cooling, outside tempera- ture, age of the milk, etc. Plant, for instance, demonstrated that milk ^vhir-li has been kept — At a ti'iiiperaturo of showe deo:. C. 8 hrs. 24 hrs. ."hides'. C. 7 hrs. 22 hrs. 37 deg. C. 5 hrs. 12 hrs. Koning- has also kept milk at various temperatures and titrated the degree of acidity after varying peiiods: Kept at 7 to 9 deg. L\ Kept at 22 deg. C Deg. of aciditv Deg. of acidity withi/ioNaOH Milk after delivery. . 13.6 13.6 After 15 hours . . ' 14.6 14.6 After 29 hours , 14.6 20.6 After 41 hours 16.0 62.6 After .53 hours 16.0 71.0 After 65 hours 16.8 After 77 hours 17.6 After 89 hours 18.8 Since the growth of various bacteria depends on the method of keeping the milk, therefore the acid formation varies in accord- ance with the same conditions during the same time. Koning's experiments confirm these findings : Time of Milk in shallow vessels Tn tall cvlinders delivery at 22 deg. at 37 deg. C. at 22 deg. ' at 37 deg. C. Shortlv after milking. 18.6 After 24 hours 16.4 18.5 18.8 32.4 The degree of acidity depends, furthermore, upon whether fresh milk is boiled or raw; in boiled milk it is lower than in raw milk, and it also depends on the aeration of the milk. Milk drawn carefully into bottles 25 minutes after the milk- ing has 17.4; after being aired by pouring from a height of V^ meter, 16.4; after repeated aeration 16.1, and after boiling- only 16 degrees of acidity (Koning). The escape of the volatile carbonic acid seems to play a part in this. Finally, the degree of acidity depends on the method by wdiicli it is tested. For instance, if the milk is diluted with water for the purpose of titration (method of Thorner, Pfeifer, etc.), then through this addition of water, a solution of alkaline calcium phosphate takes place and the acidity becomes less. Typhoid Fever from Milk. ^91 Since the acidity varies immediately after milking, after lac- tation, among individuals, and even in milk from different teats, and from interrupted milkings, the immediate measuring of the degree of acidity constitutes no proof of the age of the milk. The periodically continued titration of the same sample may, however, be a good indication as to whether the milk has passed the incu- bation phase and thereby afford an approximate indication of the ''age.'' By "age" is not understood the difference in time between milking and examination, but a condition which may ap- pear in milk sooner or later, depending on the cleanliness in its preparation and handling, and on the outside temperature. This condition is effectively determined by the reduction of meth3dene blue. ^ If the milk has once passed the incubation time the curve of acidity rapidly and progressively rises, when the milk is kept subsequently at temperatures at which lactic acid bacilli grow pro- lifically (20 to 37 deg.). Koning made a test of milk which at deliverv gave a degree of acidity of 15.8 (xV n Na OH :100), ' ^ And showed after at 10 deg. 22 deg. 37 deg. C 1 day 16.4 28.8 96.0 2 days 16.7 91.1 92.8 3 days 17.2 102.4 105.2 4 days 17.9 96.4 144.0 5 days 26.2 105.6 184.0 6 days 39.2 103.2 219.6 7 days 57.6 102.8 241.6 8 days 65.2 106.0 261.6 Since, however, the amount of lactic acid formation does not depend on the time and temperature alone, but also on the variety of bacteria growing in the milk, only general conclusions as to the aging of the milk can be drawn. Subsequent Contamination With Infections of Man. The occurrence of disease producing agents in milk is of interest from the standpoint of tracing the origin of disease, but from a milk inspection standpoint it "is a most thankless field. These disease producers may originate from affected persons, or from healthy bacilli carriers, or they may reach the milk through infected material, as, for instance, infected water used in washing utensils, or as an adulterant, or in the treatment and preparation of milk products. That milk may become a transmitter of disease has been posi- tively proven. 1. ^ Typhoid Fever. The causative agent may contaminate the milk tlirough infected water, through vessels which were returned without cleaning from houses harboring persons affected with typhoid, through affected and convalescing patients who' are employed in producing or in the subsequent handling of milk, and 192 Infections ■ of Man from Alilk. tlirougli attendants and other intermediate hosts, especially throngh bacilli carriers. Konradi positively demonstrated typhoid l)acilli in such milk. Levy and Jakobstal discovered true typhoid bacilli in an abscess of a cow so that under certain conditions it should l)e considered possil)le for typhoid bacilli to gain entrance into the milk directly from the udder of the cow. 2. Paratyphoid Fever. All that applies to typhoid bacilli holds equally true for paratyphoid, and to other bacteria of that type, for instance the Bacillus enteritidis and the Bacillus paracoli. In these affections especial attention should be directed to the animals which are affected with intestinal inflammations, purulent metritis, and acute, severe inflammations of the udder, and also to stables in which white scours of calves and calf-ill occur frequently. The possibility of the transmission of scours to man has been indicated by Lenz, Jelile and Charleton. Up to the present time, however, its certain transmissibility through milk has not been satisfactorily demonstrated. 3. Cholera. 4. Diphtheria, 5. Tuberculosis, Rabinowitsch demonstrated tubercle bacilli of human type in milk. 6. Scarlet Fever. The sanitary police or the authorities in charge of milk con- trol in all cases in which a suspicion prevails that such diseases have been transmitted through milk can provide that the possi- bility of the continued spread of such infections should be pre- vented. The sanitary police authorities should continuously im- press upon all persons interested in the production of milk, and in the dairy industry, that there are always possibilities of the transmission of disease ; and the attendant physicians should cau- tion the patients and their families as to the danger of allowing it to spread further, and any violations should be dealt with to the extent of the law. The health authorities of a locality at every appearance of a dangerous epidemic should consider the possibility of the develop- ment of the disease through milk consumption, and should trace the places from which the affected persons and their families draw their milk supply". If from these investigations there exists the slightest cause to assume that the milk supply may be the original cause, the attending physicians should cause a further investigation of the matter. In the meantime the suspected milk should be rendered harmless by pasteurization. With these remarks an intrusion has been made into the chapter upon *Hhe supervision of the milk traffic and milk control," which will be given special consideration. Destruction of Bacteria by Heat. The Destruction of Bacteria in Milk. it ' ' JTir purpose to discuss briefly the destruction of bacteria in milk, which aims to free the milk from disease-producing germs and add to the keeping quality of the milk. In practice this is accomplished most frequently by heating, in which the following distinctions are made : 1. Sterilization of the milk ; 2. Simple boiling ; 3. Pasteurization. If it is desired to judge the value of these methods of prepa- ration, the question first considered must be, what changes does the milk undergo through heating! Milk is a biological product the properties of which may be considerably influenced by cold and heat. It is generally known that after heating milk retains a so- called boiled-milk taste, and that this becomes stronger the longer the milk is subjected to a temperature of from 70 to 100 deg. C. The method of heating is important for the appearance of the cooked taste. Open boiling even for a short time produces a marked change in taste when compared with heating in specially closed utensils or in bottles after subsequent cooling. The curdling of boiled milk is more difficult than with raw milk ; the boiled milk in curdling after a long time forms a loose, coagulum with less uniform consistency. This change is not so pronounced with heating between 70 to 80 deg. as in boihng and in heating to over 100 deg. C. Depending on the height of the temperature and on the length of time the heat is applied, globulin (at 75 deg.) and albumin (at 80 deg.) are precipitated. Proteids which are precipitated m milk by heating to boiling temperature disappear if the boiling is con- tinued. According to Peiper and Eichloff the intermolecular at- tachments of the proteids become loosened by heating to high temperatures, and leucin, tyrosin, ammonia, sulphureted hydrogen and phosphorated hydrogen are formed. If the heating has been conducted in poor earthenware or glass vessels, especially new ones, potassium silicate will pass into the milk. Fynn noted the absence of sulphureted hydrogen from heated colostral milk. The reaction became apparent only on the fourth day of lactation. The formation of sulphureted hydrogen and phosphoric acid in milk results from the splitting up of casein. Hydrogen sulphide can be demonstrated in canned milk even months after heating, whereas in sterile bottled milk, under the influencee of light and m the presence ot oxygen, the sulphide of hydrogen is utilized for the formation of water and sulphur. In higher heating the milk becomes brownish through caramel- ization of the milk sugar and the lecithin content of the milk 13 194 Effect of Heat. diminishes, wliicli, according to Kida, may be seen from the fol- lowing- example : In 1000 c. e. of milk, lecithin was present as follows : Unheated samples... 0.474 gm. 0.474 0.505 0.467 0.462 0.517 Heated to 75 cleg*. . . .0.444 gm Heated to 80 deg- 0.420 0.467 Heated to 95 deg 0.349 Heated to 100 deg 0.351 Over 100 deg. C 0.401 Diminishing amt. ...0.030 gin. 0.054 0.038 0.118 0.111 0.116 In percentage 6.33 11.39 7.52 25.27 21.22 22.17 In heating, the proteids also change, peptone is formed and tricalcinm phosphate is precipitated. The original ferments are especially susceptible to the influ- ence of heat. Throngh heating to a certain temperature the amylase, the peroxydase, the catalase and the aldehyde reductase disappear. The amylase and the aldehyde reductase disappear even at a temperature of 65, that is from 50-65 deg. C. Of course milk which has been changed in this way by heat must naturally be judged differently from a nutritive standpoint than raw milk. Out of 3,462 digestible proteids used in each 100 gm. of milk there remained undigested: In unheated milk 0.762 gm. In heating for 30 min. to 80 deg. C. . . .1.153 gm. 85 deg. C... 1.493 gm. 90 deg. C... 1.420 gm. 95 deg. C 1.540 g-m. 100 deg. C... 1.719 gm. Experiments by Briickler, Reiner and Eichloff showed that dogs fed for months on sterilized milk showed a good nutritive condition, and some of them even manifested a greater gain in weight than the control dogs fed with raw milk, but the latter were brighter, their blood w^as richer in ash, with diminished salt content; it contained more fibrin, had a higher specific gravity, and the structure of their bones was more dense and richer in ash. The bone marrow of the animals fed with sterile milk was more anemic, the periosteum of the bones separated more easily, and at times hemorrhages appeared on the borders of the diaphyses, such as occur in rachitis. The nutritive results in children which have for a long time been exclusively nourished on sterilized milk are similar. The infants become affected with infantile scorbutus, a symptom com- plex, which is known to the physician as ''Moller-Barlow disease,'* and which disappears when raw milk is provided. From the above it appears that high prolonged heating of milk should be avoided, and if possible the advantages derived from the heating should be obtained by heating the milk for only Pasteurization of Milk. 195 a short time at a relatively low temperature, which when properly applied will appropriately destroy the bacteria. The vegetative bacteria may be destroyed by subjecting them to the influence of heat at 60-70 deg. C, for one-half hour, or to a temperature of 85 deg. C. for a half minute; on the other hand it is known that spores of bacteria not infrequently resist a tem- perature of 100 deg. C. and over. In practice it is advisable to abstain from the sterilization of milk with high degrees of temperature, and to apply pasteurization, since, through the usual method of sterilization the destruction of all germs is not attained and the disadvantages are too apparent. The wholesale depots may be provided with outfits for bottle pasteurization and milk heating, in which flowing milk, through the influence of steam on heating surfaces may be brought to a temperature of 85 deg. C. In heating bottled milk it is essential to observe that the milk should become uniformly heated through- out ; this is attained by shaking the milk during its pasteurization. Following this, rapid cooling should be undertaken, which is best accomplished by atomizing pipes which cause water to fall upon the hot bottles in the form of a spray. The apparatuses in which the milk flows over heated surfaces should be so constructed that all parts of the milk will come in contact with the heated surface, making the heating of the milk uniform in all parts. The utilization of the heat in some of the appliances is regulated in such a way that the cold inflowing milk is warmed by the outflowing pasteurized milk, the latter, however, being cooled subsequently. Through the exchange of heat from the outgoing stream of milk about one-half of the required heat may be saved. The efficiency of some of these apparatuses is enormous, since they are able to treat from 5000 to 8000 liters per hour. From a sanitary standpoint it is apparent that such appara- tuses must be so constructed that they may be readily cleaned mechanically, since improperly cleaned places conduct the heat poorly, and may give rise to contamination of the milk with putre- factive bacteria. In pasteurization, the same as in milk production, the greatest stress should be laid on immediate and thorough cooling, and on keeping the milk continuously cool until its consumption, since otherwise the pasteurized milk will become spoiled, and will un- dergo a form of decomposition which is very undesirable (espe- cially in bottle pasteurization). Pasteurized milk decomposes through multiplication of protein splitting, peptonizing bacteria whose spores may have withstood the heating. The vegetative bacteria, among these the lactic acid producers, are mostly de- stroyed, and except for a few resistant forms of spore bearers only heat-resisting organisms will remain viable, but these forms of bacteria are usually harmless (Rullmann, Gerber and Wieske, 196 .Effect of Heat. Buri'i, Russell and IIastiiii>s). These germs decompose proteids and carbohydrates by forming butyric acid with gas production, and peptonizing the proteids. Boiled milk decomposes more read- ily than raw milk from the bacteria which contaminate it after the heating process. Kelative to the effects of pasteurization, the following should be noted : As a result of the effect of 85 deg. C. the bacterial num- ber dropped from 10,000,000 to 500 per c. c. These remaining organisms however, which consist principally of peptonizing var- ieties, multiply rapidly to very great numbers if the milk is brought again to 25 degrees C, frequently producing changes in taste, which becomes bitter and irritating, but sometimes without mark- edly changing either the appearance or taste. This however does not render pasteurization hazardous, since it is possible through proper handling of the milk to prevent these undesirable processes. The marketing of pasteurized milk becomes dangerous only when the consumer considers that pasteurized milk being free of germs may be kept indefinitely under almost any circumstances and therefore takes less care of pasteurized milk than he would of the raw product; besides this consumers repeatedly heat such milk and thereby diminish its nutritive value more and more. It is for this reason that various authorities have taken action against the indiscriminate distribution of pas- teurized milk. It should be required that the date of pasteuriza- tion be indicated on each bottle. A statement from the officials of the city of Leipsie asserts that pasteurized milk is not more valuable than raw milk, but that it appears to be of lesser value on account of the destruction of its raw condition and the consequent chan^oes. Any manipulation of milk which claims to extend its keeping- properties by several hours, and which possibly may be used in the establishment of false valuation by statements that the milk has a lasting-, keeping quality and a freedom from bacteria, is directly dangerous and injurious to health if the consumer is not thoroughly informed with regard to the effectiveness and limitations of pasteurization. The action of peptonizing bacteria in milk that has been pasteurized is pointed out, and recommendation is made against the purchase of milk which was pasteurized more than three days previously. The official statement also calls attention to Barlow's disease, and to the dangers attending improper keeping of such luilk. Sometimes pasteurized milk which is never free of bacteria is marketed under the attractive declaration of ''free from disease- bacteria." What is the relation of pasteurization to such a claim as this? According to the experiments of Forster, van Geuns, de Mann, Ringeling and Koning, de Jong, de Graaf, and Beck, the disease-producing bacteria are affected differently by high tem- peratures while in milk than when in bouillon or water. Thus for instance heating for a half hour at 70 deg. C. is not always sufficient to destroy colon bacteria. Tubercle bacilli are still more resistant. According to Kolle and Beck they are not destroyed with certainty even when subjected to heating for a half hour at 80 deg. C, especially not when they are isolated from the influence Thermal Death Point of Bacteria. 197 of the heat by the formation of a surface scum and by coagulation. De Jong concludes from his experiments (bottle sterilization) : 1. That heating for a half hour at 71-72 deg. C. is not always sufficient to destroy the tubercle bacilli mixed with the milk. 2. That heating even to a higher degree does not always give satisfactory results since the resisting power of the tubercle bacillus varies. 3. The designation ''free from disease-bacteria" for pas- teurized milk is false. 4. Those who desire milk free from tubercle bacilli must purchase sterilized milk, provided it is not obtained from herds free from tuberculosis. Bang, de Mann and Forster obtained evidence that heating to 85 deg. C, for three minutes destroys the tubercle bacilli, a fact which has also been confirmed by the work of Weigmann and by the experiments of Tjaden, Koske and Her- tel under conditions which prevail in large distributing plants with milk from tuberculous udders. Other non-spore-containing dis- ease-producers in milk are also destroyed at this temperature pro- vided that certain conditions do not prevent proper heating. [According to the experiments of Rosenau, it is evident that the tubercle bacillus in milk loses its infective properties for guinea pigs when heated to 60° C. and maintained at that temperature for 20 minutes or to 65° C. for a much shorter time. It should be remembered that the milk in the tests of Rosenau was very heavily infected with virulent cultures, which was indicated by the prompt deaths of the control animals. Milk would practically never con- tain such an enormous amount of infection under natural condi- tions. It is therefore justifiable to assume that if 60° C. for twenty minutes is sufficient to destroy the infectiveness of such milk when injected into the peritoneal cavity of a guinea pig, any ordinary market milk after such treatment would be safe for human use by the mouth as far as tubercle bacilli are concerned. These results are substantiated by the findings of Versin, Bonhoif, Th. Smith, Schroeder, Russell and Hastings and Hesse. Relative to the thermal death point of other organisms Rose- nau found that typhoid bacilli are killed in milk when heated to 60° deg. C. and maintained at that temperature for two minutes. The great majority of these organisms are killed by the time the temperature reaches 59° C. and few survive to 60° C. The diphtheria bacillus succumbs at comparatively low tem- peratures. Oftentimes it fails to grow after heating to 55° C. Some occasionally survive until the milk reaches 60° C. The cholera vibrio is similar to the diphtheria bacillus so far as its thermal death point is concerned. It is usually destroyed when the milk reaches 55° C, only once did it survive to 60° C. under the conditions of the experiments. The dysentery bacillus is somewhat more resistant to heat than the typhoid bacillus. It sometimes withstands heating at ]98 ■ Effect of Heat. 60° C. for live minutes. All are killed at 60° G. for ten minutes. However, the great majority of these micro-organisms are killed by the time the milk reaches 60° C. So far as can be judged from the meager evidence at hand, 60° C. for twenty minutes is more than sufficient to destroy the in- fective principle of Malta fever in milk. The Micrococcus melit en- sis is not destroyed at 55° 0. for a short time; the great majority of these organisms die at 58°, and at 60° all are killed. Milk heated at 60° C. and maintained at that temperature for twenty minutes may therefore be considered safe so far as con- veying infection with the micro-organisms tested is concerned. Ayers states that the best method of pasteurization at the present time, and the one which should be used, is the holder proc- ess, in which the milk is held for 30 minutes. For this process a temperature of 63° C. (145° F.) is to be advised, since that temper- ature gives a margin beyond that sufficient to destroy pathogenic organisms, while at the same time it leaves in the milk the maxi- mum number of lactic-acid-producing organisms which cause the souring of the milk. When using the flash process, the milk should be heated to at least 160° F. Since there is almost always a fluctuation in the temperature during pasteurization, care should be taken to see that the temperature never drops below 71° C. (160° F.) in the flash process. — Trans.] Exposure at 50 degrees of temperature for 15 minutes or at 70° C. for 10 minutes is sufficient to destroy the virus of foot-and- mouth disease. The virus is destroyed instantaneously at 85 deg. C. All of these advantages may also be obtained from subjecting the milk in the household to heating for a short time without boiling, when through occasional stirring the formation of the scum upon the surface is prevented. Therefore the purchase of raw milk, whose fresh condition can be readily controlled, should be generally recommended, and the destruction of bacteria should then be carried out by simple heating. The observation recorrled by Schut appears to be worthy of consideration, namely that relatively low temperatures rapidly destroy bacteria, when applied simultaneously with a lowering of the pressure. In heating the milk at 70 deg. C. the disturbing scum formation was omitted. As accepted by Schut, in this process the steam penetrates into the body of bacteria, which explains the more eflScient action of this method. Experiments which aim to improve the keeping qualities of milk by the addition of chemical substances are very numerous. In addition to improving its keeping qualities the retention of the raw condition of the milk was attempted. This does not refer to the adulterations which are undertaken by dealers for fraudulent purposes, or which are carried out in the household, and it should be considered that all additions to milk without subsequent decla- ration are equal to an adulteration of food, changing it to a spoiled product, possibly even converting it into material injurious to health. Preserving Milk with Chemicals. 199 At that the additions do not accomplish the purpose for which they are intended in the dilutions in which they are used (Richter- boracic acid), or they diminish the utilization of milk for cheese production because they inhibit the rennet action. Soda or bi-car- bonate of soda, boracic acid and borax, more rarely salycilic acid, and recently formaldehyde are mostly used. Adulterations will not be discussed here, but only earnest scientific experiments will be taken up, in which the accomplishment of an actual improve- ment in milk has been the object sought. 1. Budde succeeded in improving the keeping qualities of milk with the aid of peroxide of hydrogen. The milk is heated to about 50 deg. C, 0.036 to 0.5% H^Os is added and it is then filled into bottles and kept for several hours at 50 deg. C. According to Lukin it is possible with pure peroxide of hydrogen, as indicated by Budde, to give the milk a low bacterial count, or render it free of bacteria. Budde 's method has not at- tained an extensive use. According to Chick, Rosam, Gordan, Bergmann and Hultmann, Eicholz, Nikoll and Duclaux the amount of peroxide of hydrogen recommended by Budde is not sufficient for the satisfactory destruction of bacteria in milk, but according to Lukin their failures were due to the use of impure preparations of peroxide of hydrogen. Tubercle bacilli and typhoid bacilli were not destroyed by this method. If the authors used 0.1% of peroxide of hydrogen, the necessary quantity to produce steriliza- tion, then the milk obtained a bitter taste, which disappeared only after the excess of hydrogen peroxide had been eliminated by cat- alase. According to Utz a small quantity of peroxide of hydrogen is retained in the milk even when used in the quantities recom- mended by Budde. De Waele, Sugg and Vandevelde, who worked with 0.3 and 0.4% of peroxide of hydrogen, have used in addi- tion small quantities of defibrinated blood for splitting up the retained HoOo. Much and Eomer employ a similar method of preserving milk which has been obtained under special precautions as to cleanli- ness. The milk is filled into sterilized bottles, mixed with 0.1% of peroxide of hydrogen, and kept for one hour at 52 deg. C. For the destruction of the H2O2 in the milk, hepin, a catalase prepared from liver, is added to the milk before its consump- tion. Since the hydrogen peroxide milk is very sensitive against the influence of light (when exposed to light it very readily be- comes bitter, tallowy and rancid), it is best to keep it in green bottles and in a dark place. Even with these precautions a change in the taste may become apparent after two weeks. Injurious action of the peroxide of hydrogen if used in these quantities should not be feared; the results in infant feeding are supposed to be favorable. The milk which is freed from the retained peroxide of hydro- gen by the addition of hepin should be immediately used, since it 200 Effect of Chemicals. is no longer resistant to decomposition tlirougii bacterial con- tamination, after the liepin has been added. 2. Years ago von Behring reconnnended the preservation of milk by formaldehyde. Experiments upon animals showed that the addition of formaldehyde to milk in the proportion of 1:1250 gave it no ])roperties injnrions to health by any method of appli- cation (even intra venonsly), and it was further found that animals with a very delicate sense of smell failed to recognize the presence of formaldehyde if it had been added to the milk in a dilution of 1 :10,000. The action of formaldehyde in such dilution is quite marked. The addition of a 1 :10,000 dilution postpones coagulation for many days (von Behring, Price and Schaps) ; 1:25,000 and 1:40,000 prevents coagulation from 1 to 4 days (KoUe). The action of formaldehyde was found to be more effective in accord- ance witli the cleanliness of the natural milk and this action ac- cording to Rothschild and Metter appears to result from the fact that the lactic acid bacilli chiefly succumb, whereas the other saprophytes are harmed to a lesser degree. Tubercle bacilli are not influenced in their viability by these dilutions. The feeding of infants for weeks with formalin milk (addi- tions of 1 :25,000) may result in an injury of the kidney epithelium of the children, which leads to the elimination of albumin. Ac- cording to Baudini the rennet pepsin and trypsin action may be considerably inhibited by formalin ; the acidity of the milk is increased. In the experiments of von Behring the action of formalin depends upon its effect in checking the development of bacteria, and not on its disinfecting or sterilizing property. A concentration of 1 :25,000 up to 1 :50,000 has no influence on the t>T5hoid and colon bacteria and staphylococci (Vaughan and Schaps). Diphtheria, colon and pyoc3^aneus bacilli have not been destroyed even in dilutions as low as 1 :5,000. Tubercle bacilli are protected by their waxy covering even against higher proportions of formalin, and as a matter of fact formalin is used, on account of its action on other bacteria, for the purification of sputum for the purpose of cultivating the tubercle bacilli from the saliva. Formalin milk constitutes a food whicli should be designated as spoiled and injurious to health. 3. Seiffert worked out a method of milk preservation in which the bactericidal action of ultra-violet rays is used for sterilization of milk. The method of action of the ultra-violet rays has not yet been satisfactorily explained. According to Lobeck (cited by Grimmer) the exposure of water to such rays produces peroxide of hydrogen. Grimmer believes that the latter is also formed in milk, but on account of the catalectic factors of the milk it immediately decomposes again. It is possible that the forma- tion of peroxide of hydrogen constitutes the germicidal power of ultra-violet rays. The milk fat is not changed (Lobeck). Ac- cording to Dreier-IIansen the proteid is coagulated after a pro- Ultra-violet Rays. 201 longed exposure of milk to such rays. Seiffert passes the milk in broad bottles along the illuminating bodies, allowing the rays to act upon the milk for about two minutes. He employed Leyden jars fitted with aluminum or cadmium points, which are charged with a current of high tension through an inductor which dis- charges mutually. Gerber and Hirschli used for sterilization the uviol light which is rich in ultra-violet rays 5 he was unable how- ever to demonstrate a marked reduction of the bacterial content by subjecting a layer of milk of 1 mm. thickness to its influence, whereas Finkelstein and Lobeck, Henri and Stodel, Billon and Daguerre obtained good results with the ultra-violet rays from mercury and quartz lamps. According to Billon and Daguerre sterilization may also be accomplished when milk is exposed to white light in violet glasses. The action is the best when the white light is split up by a prism. Eomer and Sames, who also conducted experiments on the bactericidal action of ultra-violet light proved that market milk which has been exposed to the rays of a Heraus' mercury-quartz lamp of 6 ampere strength in a quartz alembic (at a distance of 15 cm. from the source of light the action of which has been in- creased by a reflector) caused a reduction from 98,900 original bacteria after one hour of exposure to 16,500 bacteria ; after 1% hours to 8750 ; after 21/0 hours to 2,050 bacteria. The taste of the milk was pronouncedlv irritating. In a second test the number of bacteria diminished from 111,800 to 94,000 in 10 minutes, and to 65,500 in 20 minutes. On the surface of the milk a yellowish scum forms. The peroxydase reaction of the milk is destroyed after a prolonged exposure to such light. [The experiments of Ayers and Johnson indicate that with quartz mercury vapor lamps of the present power and construc- tion it would not be possible commercially to completely sterilize milk by the ultra-violet rays. It might be possible to obtain bacterial reductions as great as by pasteurization even on a commercial scale by the use of large revolving drums and a number of lamps. However, in milkso treated there would be no assurance of the complete destruction of pathogenic organisms since the rays do not seem to exert any selective'destruckve action on vegetative cells. Of course since pathogenic organisms might be assumed to be present in a small number in proportion to the total bacteria in milk, if 99.9 per cent, of the organisms present were destroyed, it might be assumed that the pathogenic bacteria would be destroyed. This process, however, would not afford the same security as does proper pas- teurization. Then, again, it would be difficult on a large com- mercial scale to constantly control the factors which influence tlie bactericidal action of the rays. It is also doubtful if the lamps could be made to successfully 202 Effect of Chemicals. compete with the present method of steaming milk bottles in order to partially sterilize them. From these experiments it appears doubtful if ultra-violet rays can be used on a commercial scale to replace the process of pasteurization. However, it may be possible to use the rays, in combination with pasteurization, in the preparation of a special milk with a low bacterial count, provided there is a demand for such milk in limited amounts for the use of infants and invalids. — Trans.] 4. Other methods of preserving- milk are its saturation with carbonic acid under strong pressure, its ozonisation, and its sterili- zation with electrical currents. The carbonization recommended by Hoffmann, van Slyke, and Bosword, the ozonisation advised by Dorn, and finally the steriliza- tion through alternating electric currents of high tension recom- mended by Guarini and Samarini have not yet attained any prac- tical significance. The best means of imparting keeping qualities to milk are cleanliness in its procurance ; the only method of preservation which should be generally permitted for milk is proper cooling. This concludes the theoretical consideration of milk. In the following chapter the method of control of milk in general will be discussed, and finally the method of milk examination will be taken up with emphasis on the points which appear especially important in the examination of market milk and for the ex- aminations of individual samples of milk. Chapter IX. MILK CONTROL. The sanitary police control of foods has advanced greatly in importance during recent decades. The study of diseases of nutrition in general and the solution of the etiology of these affec- tions have resulted in a recognition of the necessity for the estab- lishment of measures relative to the quality of food substances, and have led to the formulation of laws, ordinances and regulations. The most extensive development in this relation is shown by the importance of the meat -inspection law, which has been advanced to correspond with the value of meat as human food. Instead of controlling the marketable meat products in the shops, the most important part of the inspection is placed at the point of meat production, that is, in the abattoirs. With the exception of the so-called home slaughtered meats, not a single pound of meat is consumed or used for food products in Germany, without being first subjected to inspection. The meat consumption per capita in Germany in recent years has amounted to from 103 to 110 lbs. In addition to the value of the meat produced, the amount of milk consumed should be con- sidered, there having been made an approximate estimate of an an- nual production of 7 billion gallons of milk, the smaller portion of which is utilized as drinking milk, the larger part for the manufac- ture of milk products as cheese, butter, etc. According to statistical compilations, in 1905 the quantity of milk consumed per capita amounted in Berlin to 106.5 liters (30 gal.) in Munich to 131.5 liters (37 gal.) in Hamburg to 137.5 liters (38 gal.) It is gratifying to note that the consumption of milk in Munich has' increased during the last decade, and when its nutritive value is considered its low cost as a food stuff is quite apparent. The amount of milk and meat consumed in Munich per capita is as follows : 1900 : Milk 130 liters (36 gal.) Meat 81.8 kg. (180 lbs.) 1904: Milk 131 liters (37 gal.) Meat 75.1 kg. (165 lbs.) 1908 : Milk 149 liters (41 gal.) Meat 85.9 kg. (189 lbs.) and without doubt milk consumption will still continue to increase 203 204 ^rilk Control. if the cost of all other foodstuffs continues to rise. There arc no means by ^^ilich the imtrition of the people conld be increased to better advantage than by increasing their consnniption of milk, since it has not yet reached the high point warranted l)y the valne of milk as a nntritive snbstance. From the various discussion in this work, the importance of supplying consumers with milk of good quality is apparent. An increase in milk consumption is of equal importance to the interest of the nutrition of the people and to the interest of agriculture. This increase however can only be obtained when, in addition to an educational propaganda regarding the nutritive value and cost of milk, care is taken to rectify the generally existing evils attend- ing its production, by which means the milk will be brought up to a standard, which may reasonably be required of any food. There- fore it should not only be unadulterated but must be produced and delivered in a clean manner, in an unspoiled, fresli condition, and possess no disease-producing properties. The important sigiiifir-ance of liealtliy milk as food for the people, especially for infants, has been emphasized by physicians, hygienists and veterinarians in numerous special articles, which have argued for and against the desirability of gaining nutrition through the use of market milk. Public interest and private philanthropy have accomplished a great deal of good by the establishment of infant milk depots. Such establishments are frequently attached to the abattoirs, and are conducted under the successful direction of veterinarians. It is impossible to enter here into a discussion of such establishments, since this field constitutes only a small branch of the great question of the milk supply. While the determination of the causes of the so-called dis- eases of nutrition may not yet be sufficiently clear, the general and local surroundings of the patient or other conditions may influence the course of these diseases. This is particularly true in summer mortalities of children, as in these diseases various conditions, such as want of natural nutrition, faulty housing, etc., may all play a part as factors. Nevertheless, from the experience of specialists the conclusion must be drawn that a strict sanitary police con- trol must be established in order to protect human health as much as possible from the ills occasioned by dangerous milk. Such harm may result from the consumption of: 1. Milk from diseased animals, 2. Milk originally wholesome but which has been subse- quently contaminated with bacteria pathogenic for man, 3. Milk, which has been spoiled by any kind of decomposi- tion, or which is beginning to spoil, 4. Milk containing chemical preserving substances. These are briefly the points which in themselves prove the value of hygienic control of the milk traffic, and their elimination, witli as much consideration as possible for the economic impor- tance of the various factors, must be constantly kept in mind. A proper execution of sanitary police regulations governing milk traffic is not only of importance for the health of the people Advantages of Milk Examinations. 205 but attains even greater value for the milk industry and general agriculture through the indirect advantages which result from their enforcement, such as the improvement of the herds, etc. Measures which are in perfect accord with the hygienic require- ments of milk traffic, are at present enforced by most cities, which have adopted various forms of ordinances and laws to cover this subject. Some of the states and the federal government also pro- vide for certain additional control. The milk control stations of several cities in Germany have attempted to produce an improvement of the milk traffic by the establishment of proper ordinances. Even the best organized stations confine themselves almost entirely to the control of the finished product offered for sale, and therefore they are limited to the examination of samples. If the existing distribution of milk and extension of deliveries in large cities are considered it would require an army of officials to take samples and examine them, in order to test all the milk delivered to ascertain its value as food. Even in the eventual centralization of the milk traffic, ap- propriate examination of market milk from a hygienic standpoint will be impossible, since in each shipment too many questions would have to be solved, and besides this, Ave have not at our com- mand reliable methods for examining the finished market milk rapidly and thoroughly. The advantages of market milk examinations, which should not be underestimated, consist in the fact that it is possible to detect gross neglect and wilful violations, by which in many cases guilty parties may be held responsible. The knowledge that he is under observation, and the fear of punishment compel even the most indolent milkman and dealer to give increased attention to production and handling, including transportation. In some cities of Germany a great deal has been accomplished in the con- trol of market milk, but an effective improvement is prevented by the existing methods of milk officials. Whatever has been ac- complished through the control of market milk, it is slight when compared with the requirements of the law and regulations. If milk control is confined in a one-sided way only to adulteration, preservation and to the dirt content, or to fermentation tests and acid content, as they are mostly practiced, it is hardly possible to expect proper improvement from a hygienic standpoint. Food chemists have been the chief officials engaged in milk control up to the present time, since the principal stress has been laid on the detection of adulteration or of attempts to improve milk by the use of preservatives. The author considers it as ab- solutely essential that this field of control should continue in charge of chemists, since the physico-chemical properties of milk require a great amount of special training if the results obtained by examination are to be subjected to critical judgment. ' This however does not infer that veterinarians, physicians or other 20G Milk Control. persons who have obtained special training liave not the same right to take up the work against violators. It is immaterial who executes the work if it is only carried out properly. Chemists, veterinarians and physicians have their special sphere of activity in milk control, and all should work in harmony that they may accomplish the desired results, each profession exerting all its power towards improvement of the milk supply from the time of its production until its distribution to the consumer. It is deemed advisable to introduce here a short description of milk control in the City of Munich : The beginninp: of control in Munich can be traced back to 1834. Police authorities brought to the police physician samples for examination. With the taking over of food inspection by the magistrate in 1862, market inspectors, and in 1876 district inspectors, ■were detailed to take samples and to make the preliminary examinations under the direction of district veterinarians. The latter were required to carry out the scientific examinations and to pass judgment on the samples. By an agreement of hygienists, food chemists, dairy experts and agriculturists, the latest local police measures were inaugurated in 1906, and at the same time the inspection forces were reorganized. The city was divided into six control districts, and the inspectors assigned to these districts had to carry out the requirements of the authorities and the experts relative to the supervision of the milk traflfic. The scientific part of the inspection is conducted in the corresponding divisions of the examining station, that is in the chemical and the veterinary bacteriological divisions. Assistant inspectors are assigned to the inspectors for aiding them in the work and for the transportation of the samples. The inspectors are required to supervise the execution of the regulations and to report any violations of these measures to the milk control station. The supervision should be adapted as far as possible to the hours in which the business, sale and operation of the milk establishments are carried on, but may be carried out at all hours of the day and night, and it should be so regulated that the dairies at no time could feel safe from the restraint of supervision. The duty includes: 1. The control of and supervision over all milk brought into the city, all milk which is in traffic within the city, all transportation containers, all dairies, milk shops and production establishments within the city limits, and the taking of samples. 2. The procuring of necessary milk samples for examination, both from stable and salesroom, and of other material necessary for evidence. 3. Conducting research work in individual cases, and making out reports and complaints. All collected samples of milk, samples of other food substances which are sold in the dairy, milk cans which do not correspond with the regulations, various containers in which the milk is kept, measured and sold should be submitted at the milk control station for opinion. A report should be made on the fittings and condition of the rooms and premises where the milk is stored, and from which it is distributed. The transportation of the milk samples to the official milk control station should be accom- plished immediately after the sample is procured. A preliminary examination precedes the taking of samples by the inspectors, which consists in an examination by the senses (appearance, odor), and in the use of the laetodensimeter and thermometer. The trans- mission of the samples to the scientific division is accompanied by forms on which the results of the preliminary tests are indicated, and they also give the date, hour, place of collection, origin of the sample, name of the dealer or producer, number of the sample, and its relation to a certain case. The samples are immediately examined in the scientific division, the inspectors are informed of the results as soon as possible, and their subsequent procedure in special cases is indicated by the recommendations of the experts and the director of the station. If stable control and the taking of samples in a stable outside of the city limits appear necessary, or if such are suggested by the scientific workers of the official milk control station, the inspector obtains these samples after obtaining, through the city authorities, permission to go upon the premises. In taking samples in a stable the princii^al stress must be laid on the dairy management and therefore preliminary tests of the samples taken in the stable are eliminated. The scientific experts attach their Co-operation of Officials. 207 opinion to the reports of the inspectors, the full report, with the result of the researches, being transmitted through the official control station to the magistrate, who, depending on the case, transmits the material to the proper courts. ^ ■,.... The separation of the laboratories into a chemical and a bacteriological division has already been briefly mentioned. The chemical division examines for simple and combined adulteration by the addition of water, removing of the cream, or both by establishing the specific gravity, the fat contents, calculating the amount o± to.al solids and the fat-free solid content, determining the refraction index of the milk serum by the nitrate test, testing for the degree of acidity and testing for other chemical adulterations. The bacteriological division examines as to fitness tor ccra- sumption by establishing the purity, odor, taste, consistence, age and freshness, the raw condition, intermixing with secretion of animals with affected udders, etc. ihe procedures of each division are kept separate as much as possible, and this separation of the divisions has proven of splendid advantage. Co-operation between these divisions when the work overlaps, and mutual support aid in the success. Owing to the activity of the official milk control station it was soon noticed that marked adulterations had become very rare, and that objections and condemnations on account of gross con- tamination were reduced to a minimum. Considerable objection still exists relative to the transportation cans which are frequently used in a most insanitary condition. The regTilations relative to the proper closing of the cans are now almost uniformly observed. The acid content of the milk is only exceptionally increased by fermentation, and the spoiled milk originates usually from milk collecting establishments and cheese factories, whereas individual producers as a rule supply fresh milk. The increased degree of acidity is traced in most instances to improper cooling, dirty trans- portation cans, mixing of fresh and old milk and adulteration with skimmed milk. Preserving agents scarcely ever come into con- sideration in Munich. It is to be regretted, however, that the limits of milk control activities have apparently been attained, in so far as they concern the testing of milk ready for consumption. Nevertheless, attempts have been made by extending the control to the stable and to the producing animal in order to further improve the milk supply. In certain cases good results have been obtained through giving in- structions and warnings as to the requirements, or at least in ad- vising the adoption of all precautions which are possible in prac- tice, for instance in the streptococcic mastitis question, which this city was first to take up on practical lines on a large scale. The results attained are by no means to be underestimated, but while there is no doubt that with the hard battles considerable results have been obtained for the moment among a small percentage of the producers, still no one can offer a guarantee that even on the morrow the same conditions will not prevail as formerly, and in this lies the insufficiency of market milk control and of the system of taking samples from time to time. In the future other measures will have to be given consideration in sanitary milk inspection, if it is desired that conditions which are frequently intolerable, and which prevail at present in the milk industry, should be eliminated. A guarantee of good and harmless quality for market milk 2(1S Milk Control. forms an absolute liygionie reqivireiiiont, and at the same time it is the prerequisite for increasing- milk consumption to its full ex- tent. This can be attained only through strict lei^ridation and flawless supervision of the milk from the bei>innino' of its produc- tion up to the time of its delivery, taking advantage of the great progress which has been made by science in recent times. Milk hygiene must connnence in the stable. A perceptible step in advance is gained by the introduction of stable super- vision. The preliminary requirements for the production of un- objectionable milk are healthy milking animals, healthy udders, healthy milkers and clean utensils and surroundings. In this in- stance the veterinarian is the jiroper counsellor, his preliminary training offering the necessary assurance that these requirements for well-managed dairy business will be fulfilled. Besides the ex- amination of the health of the cows, the supervision must be ex- tended to the care of the animals, stable conditions, and the keep- ing and feeding of the animals. The necessity for the most strin- gent cleanliness in milking and for the careful preparation of the milk by means of filtration, and cooling must always be impressed upon the dairyman, as well as the necessity for satisfactory transportation. Some hygienists consider the processes of decomposition brought on by contamination and improper treatment of milk as especially important causes for the rapid spoiling of milk. The author considers that their special significance should be laid, in cases of milk poisoning the same as in meat poisoning, to those disease-producers and their products which prove toxic in the animal body, and which originate in the milk-producing animal. The veterinarians prove their value in sanitary police supervision of milk production, by seeing that the cities are supplied with good milk, suitable as food for infants, and by watching the dairy indus- try. This supervision at the site of production produces better results than the most painstaking and well organized inspection of the finished product. The great dangers which threaten man through the causative agents of septic metritis, acute and chronic mastitis, enteritis, etc., are considerably reduced. The control of the milk traffic and milk industry requires especially the co- operation of all factors which come into consideration. Until uni- form regulations for sanitary police supervision are established it will remain the duty of veterinarians and physicians to point out the importance of hygienic measures to the producers through con- tinuous education, indicating also the economic advantages which ma7y^ be gained for their own interests. In northern Bavaria the supervision of stables, dairies and distributing stations has already been inaugurated by the employment of district dairy inspectors. Through periodical stable inspections considerable advance- ment could be made at the present time. This supervision should not only include the so-called certified milk or infants' milk, but Supervision of Milk Production. 209 also the production of all milk consumed, since the largest pro- portion of the parents of infants and consumers in general cannot purchase certified milk, and the children of this class who cannot afford to buy certified milk are the ones principally exposed to the dangers of infant mortality. Such classifications of milk may be of advantage to the milk trade, but they must not be taken into consideration by sanitary officials who are supervising the milk traffic. We are clear with regard to the ultimate aims which we must bear in mind in the sanitary police supervision ; whether these aims will ever be realized is a question of economic and social con- ditions. At the present time the attainment of the ideal goal_ of flawless supervision of milk from its production to its consumption is made very difficult by these very conditions. As long as the cheapness of milk as a food product for the masses stands m the foreground in the interest of the people, a place in which it actually must stand, a proper, thoroughly organized control of the pro- duction can hardly be inaugurated. Eeeommendations for sucli control have teen made by Meinert and others, and recently by Schern. For an effective execution of control over the production of milk, supervision must be established in both city and country. Milk is produced not only in the countrv but also in the city. All milk produced must be subjected to uniform control. Within these districts of control the milk-producing cities should therefore be included. A veterinarian periodically examines the dairy herds and the milk ot each animal, the individual animal in these districts, etc., without previously giving notice to the owner of the animals as to the time of the inspecton. In this inspection the milkers are also observed as to their state of health. The procured milk is examined to see whether it is clean and sufficiently cooled. The stables are examined to determine whether they meet the requirements as to light, ventilation and cleanliness. _ The control of production is linked with the supervision of transportation in certain milk-collectmg places, and finally the inspection of the dealers at the place of consumption follows. Such a complete supervision is not considered possible in practice without considerable increase in the cost of the product, and this should and must be avoided. The sanitary milk officials will have as their most important duty the finding of ways and means for the practical execution of supervision, which may be accomplished without great economic losses of production and efficiency, and without injuring the other factors in the milk industry. Meinert believes in the possibility of supervising the places of production under supervision of the state, by the appointment of physicians, veterinarians and practical agriculturists for this purpose. For each township the milk producers should select trustworthy men as supervisors, who by means of frequent examinations at the time of milking should -convince them- selves of the manner in which the requirements of the legislative measures are being observed. The activity of these supervisors should be principally along educational lines. These men should call the attention of the owners to existing deficiendes m the management of the dairy, they should offer remedies to eliminate these deficiencies, and after the lapse of a certain time, they should satisfy themselves that their advice has been carried out. In ease of disease of the dairy cattle it should be reported to a veterinarian for consultation and judgment. The supervisors should be instructed as to their duties by the official veterinarians. Creamery corporations could select their - own supervisors instead of depending on the local supervisors for the inspection of the dairies producing milk for their plants. Larger establishments could voluntarily subject themselves to direct state control. Besides this practical supervision, the district veterinarian should examine the animals every three months as to their condition of health, and judge the character of their milk. Persons who are connected with the procuring and handling of milk should be placed under the control of an official physician. The producers, supervisors, milkers, and all persons connected with the dairy should be examined as to the possibility of. their transmitting human diseases to the consumer through the milk acting as an intermediate host, and the supervisors should report their observations as to any sickness among the attendants to the physician m authority. The entire system is subject to control bv the state, which appoints its own officials for larger districts to carry out the supervision of the work. 210 Milk Control. It must always be considered that the populace has an interest not only in the prociirance of unadulterated and unspoiled milk, but also in having the milk marketed at such a price that it may remain accessible as a product of consumption for the masses, and if possible its consumption should be increased. Accordingly too far-reaching', stringent requirements should be avoided, as well as all requirements that cannot be met bj^ the prevailing condition of production, on account of financial and technical grounds. Healthy dairy cattle and the best possible cleanliness of the stables and surroimdings are more important than special feeding regailations, or requirements for stable buildings which the small farmer is not in a position to adopt. In order to prevent too stringent, or one-. sided requirements altogether, the adoption of a uniform standard would be necessary for the entire countrj^, and each state could establish its own regulations which would conform with the con- ditions of that particular localit}^ The introduction of the terms "inferior value" and ''conditionally passed" for certain low grades of milk would reduce the economic loss which results from the use of the terms ''spoiled," and "injurious to health." If stable inspection is inaugurated, a thorough organization may conduct a supervision by which the owners of small herds can also comply with the requirements. The present system of milk inspection not infrequently fails to include such small dairies be- cause the supervision of the entire milk traffic is extremely dif- ficult, but with the introduction of stable inspection the enforce- ment of hygienic requirements that shall include the small pro- ducer will be found to be not only practicable, but also very de- sirable. Dairy associations and contractors mtli co-operative creameries should regulate fluctuations of deliveries and consump- tion, so as to provide the best possible utilization of the excess of production, or the milk which has been declared by the city in- spectors as unfit for drinking purposes may be conditionally passed if desig-nated as inferior milk. Such a system has been adopted by the dairy association of Hamburg, in order to meet the economic losses caused by the stringent enforcement of the milk inspection regailations. The author believes that with legislative regulation of milk inspection, and especially with supervision of the production, it will be possible, even with the newly created conditions, to supply the population with good, clean, wholesome milk at relatively low prices. With good will and co-operative work, as well as with con- siderate enforcement of the regTilations, the desired goal may pos- sibly be reached within a short period of time. Chapter X. MILK INSPECTION. (a) Taking of Samples. 1. Market Milk. The taking of tlie sample must take place only after the fat of the cream gathered during transportation has been sufficiently distributed through shaking or stirring. Especial attention is required when separation has occurred through freezing. ., ,, i , 2. Stable Samples. The inspector who takes the sample must have his whole attention directed to the production and handling of the milk, as the people suspected of adulteration often display unbelievable slyness in order to deceive the inspector. Particular care should be taken that the mixing tank or vat does not leak, that the milk pails and other vessels do not contain wash water, and that, during the milking, the milk is not adulterated with water from bottles hidden in the clothing of the milkers ; it is important that the milking should be complete. If nitrate has been found in a suspected sample, a water test for nitrates should be made from each well at the place of production. Only after milking, are inquiries to be made regarding the feeding, keeping, care, and condition of the individual animals, etc. The stable samples must be thoroughly mixed. - 3. At least I'o liter should be taken from each market or stable sample, in" order to have sufficient material for all examinations. 4. When the samples have to be carried a long distance to the place of examination, they must be preserved with . 1% forma- lin. For chemical examinations 0.1 fo of potassium bichromate is permissible, which is obtained by the addition of a 1% solution to 100 parts of milk. The addition must always be_ stated. For bacteriological examinations, the preservation of the sam- ple is not permitted, except in cases where a microscopical exam- ination only is desired for the determination of inflammations of the udder or the presence of tuberculosis. 211 212 ^lilk Iiisi)ec'tioii. 5. The sample bottles nnist ])e filled Tip to the neck, in order to prevent the foi-mation of butter during- transportation. 6. The bottles should be closed so that an unauthorized open- ing is excluded. The transportation to the place of examination must take place as soon as possible after the taking of the samples, and if transported by rail, sufficient packing should be provided to pre- vent breakage of the bottles. If samples are desired from individual cows and not market or mixed milk samples, smaller amounts, for instance, 100 gms. or less, are sufficient, provided that only an examination for in- flammation of the udder is involved. With samples taken for chemical examination from individual cows, a complete milk- ing is necessary for satisfactory results. If examinations as to changes of milk through diseases are to be made, at least y^ liter must be sent in from each milking until the day after recovery. In certain cases, for instance, with emergency inoculation in foot- and-mouth disease, the taking of samples must begin before the inoculation and continue until complete recovery. "When examinations for inflammation of the udder are desired^ the sample of milk may be poured into a reagent glass by means of a dipper, which must be thoroughly cleansed after each sample, or, the samples are taken in such a manner that in pouring the milk from each cow from the milk pail into the cooler, the opening of the reagent glass is kept in a position to fill the glass. In taking samples from each quarter, it is advisable to milk the secretion of each quarter in a cleanly manner into the reagent glass. The sample is taken from the middle milking, that is after the quarter has been partially milked. All samples have to be accurately marked according to cow and quarter. In protracted examinations, for instance, for the detection of tubercle bacilli, it is recommended to divide the animals of large herds into groups, and to collect the milk from each five or ten cows into a sample bottle. For the determination of dirt in milk, which rapidly sinks to the bottom, it is recommended to take an average sample from the well-mixed milk, and allow the sediment to settle in a separate container, which is examined after the milk is poured off. After arrival at the laboratory, the samples must be examined as soon as possible ; however, until the examination, they must be kept in the ice-l)Ox or in the cooler. (b) Examination of Milk. The veterinarian may have to perform the preliminary testing of milk as to adulterations, but he will especially have to consider the changes in milk which are caused by animal diseases, inflamma- tion of the udder, or he has to pass judgment on possible changes caused bv certain external or internal influences. A final opinion Adulteration. 213 should never be given, except after a most intimate knowledge of the special conditions. Milk mixed from many cows has to be judged differently from milk of one or a small number of cows, because in the latter case the fluctuation through internal or external influences may be very marked, whereas the presence of abnormal secretions from one or several cows is either modified or concealed through mixing their milk with that from many healthy cows. An adulteration should never be estabhshed or the degree _ot adulteration calculated, without making comparative tests of satis- factory samples from the same source. A definite diagnosis of the degree of adulteration based merely on the values of accepted averages, normal or experimental, would be erroneous, of which no scientific milk inspector should be guilty. Before the beginning of the examination, each sample should be sufficiently mixed by shaking, without having any considerable amount of air shaken into the milk. The testing of milk is divided into the preliminary examina- tion and the special scientific examination. Through tests by means of the senses milk is first examined as to the color. Adulterated market milk is often bluish, and secretions from animals with udder diseases often make the milk reddish. . The odor is determined either immediately after emptying the cans or in the laboratory by heating the milk in glass beakers up to the formation of steam. The odor of good and palatable market milk may even vary considerably. If, however, special odors are very conspicuous, the presence of certain milk defects must be considered, possibly as the result of bacterial action. The consistence of the milk should not be too thin or watery, (suspicion of adulteration), and neither should it be sticky, slimy, greasy or curdling, which changes indicate diseases, particularly udder affections, or the presence of certain bacteria of milk which have propagated since the milk was secreted. A fine vesicular foam appearing after shaking should rapidly become large bubbles and disappear. The remaining fine vesicular foam is the result of shaking soapy milk. The taste is to be judged in the same manner as the odor. The milk should be delivered and sold in a cold condition, and therefore in the collection of all samples of milk the temperature should be ascertained. With market milk the positive result of the boiling test, that is when the milk curdles, is a sign of advanced decomposition (10 to 12 degrees of acidity according to Henkel-Soxhlet). With the fresh milk of individual cows, curdling after boiling indicates inflammation of the udder, the curdling being mostly limited to the milk of individual quarters or to the colostral milk at the beginning or at the end of lactation. 214 Milk Inspection. The alcohol test also curdles market milk wliieli lias become spoiled (8 to 9 degrees of acidity), A positive reaction with fresh samples from individual cows or with samples from separate quarters indicates either a physio- logical or severe pathological inflammatory condition of the milk glands. The milk is mixed with an equal amount of 68% alcohol. Kecently, the alizarol test has been reconunended for the de- tennination of spoiled milk. Milk mixed with an equal part of alizarol becomes brownish violet, as long as it is fresh and not spoiled ; otherwise the color turns brown and yellow, and the milk curdles, with the formation of thick flakes. For the control of market milk or for the diagnosis of udder diseases the author found that the alizarol test (milk with 68% alcohol and as much alizarin as is soluble) is without any value in testing samples of individual cows or quarters. The degree of acidity of the milk is established by titration with standard alkali. 1. According to Henkel-Soxhlet, with ^ normal sodium hy- drate solution, fresh market milk has about 6.0 degree of acidity. 2. According to Thorner and Pfeifer, with tV normal so- dium hydrate solution in 10 c. c. of milk and 20 or 40 c. c. of water, respectively, with 5 drops of a 2% solution of phenolphthalein (the figures thus obtained are multiplied by 10) fresh milk has about 18 degrees of acidity. According to Henkel-Soxhlet, the acidit}?- is determined by titrating 50 c. c. of milk, to which 2 c. c. of a 2% alcoholic solution of phenolphthalein have been added, to a faint but permanent pink. Each % c. c. of alkali (i/4 normal sodium hydrate) corre- sponds to a degree of acidity. Scliern utilizes 10 c. c. of milk and titrates drop by drop with 1/40 normal sodium hydrate solution after having added 1 to 2 drops of the solution of phenolphthalein. The titration takes place in a mixing cylinder Avhicli is so graduated that the difference of the level of the fluid before and after the titration shows the degree of acidity. An increased degree of acidity in market milk, for instance, 7 or more after the method of Henkel-Soxhlet, does not always indicate a spoiled condition. This can only be presumed when the increase of acidity in a certain time and at a certain temperature is very rapid, in other words, when the curve of acidity is abrupt. After 12 to 24 hours the degree of acidity is again determined. Fresh milk, kept at 20 degrees C, shows from 10 to 15 to 20 de- grees of acidity after 24 hours. Milk at the end of the incubation period, before bacterial multij)lication begins, has 25 to 30 degrees of acidity, and old milk 30 to 40 degrees. The increase in degrees of acidity between fresh milk and older milk is caused by the for- mation of lactic acid. One c. c. of 14 normal sodium liydrate=22.5 mg. lactic acid, and 1 c. c. of xu normal sodium hydrate=9 mg. I-Ioyberg's Test. ^15 lactic acid. In spite of this, the degrees of acidity of Henkel^ Soxhlet cannot be computed into the degreesof acidity of Pfeifer because through dilution with water the solution of slightly soluble phosphates decreases the degrees of acidity obtained anc^ there- fore, the degrees of acidity of Thorner and Pfeifer show lower vabie^ than those of Henkel-Soxhlet. Milk from individual cows often have greatly decreased or increased degrees of acidity. The decreased, ^r, more rarely in- creased degree of acidity of a single sample creates tjie su^Pic^^^^ that the cow is suffering from udder disease. Hf h f iditj of all four quarters is present with colostrum and m milk of fresh cows. The S from cows at later periods of lactation is frequently alkaline and has a lower degree of acidity. Dropped on litmus paper, market milk shows an amphoteric reaction. Alkaline reactions of single samples must be judged the same as low degrees of acidity. If market milk ^liows an a ka- line reaction, an alkali may have been added for Preservation. The reaction of market milk is acid to rosohc acid On the aclcli- tion of alkali to milk, the milk, upon adding rosoic acid-alcohol turns rose red. With fresh single samples of milk the red color after the addition of rosolic acid-alcohol is an indication ot the presence of inflammation of the udder; cows m the late periods of lactation may also show red coloring of the milk. To lacmoid the milk is alkaline, and also to dimethyl orange. The so-called Hoyberg test to determme - fibrin and pus in samples of milk from individual cows is based on the difference in the reaction of the milk. mt /• v -t i The test is conducted so that 5 c. c. milk (individual cows or quarters) are mixed with 5.5 c. c. solution of rosolic acid ^^dllch is prepared from 0.45 c. c. of a 1% solution 5 c. c. plus alcohol. A positive reaction to the test creates suspicion while a nega- tive result does not exclude it. . ^ ^ ^^ -^ As the reaction of milk from diseased quarters frequently is perfectly normal or acid, the test does not compare with the Trommsdorff test, and especially the microscopical examination.. Besides, it is very difficult to distinguish the fine differences m the color shades. . „ „. ,,, ^ ^^-, The determination of the alkalinity of milk with to noimai acid has so far not been adopted in practice. ^ - The dirt content of milk should not be weighed, as recom- mended by Eenk, since the amount of visible foreign material should not determine the disposition, but rather its quality should be considered. Besides, much dirt is dissolved m the milk, which neither can be determined through filtration nor through weighing the filters. The amount of dirt is estimated m degjees, through the sedimentation method or through filtration, and tne quality is thus determined; as a rule it represents remnants ot feed, feed dust, portions of litter, manure of cows, cow hairs, etc. 216 Milk Inspection. From the iniifonnly fine or coarse particles of dirt in milk, or from the presence of cow hair in large amounts and larger par- ticles of dirt, it may be determined whether the dirty milk has been strained after the milking-. Tlie filtration methods in which disks of cotton are used as filters have an advantage in that they indicate more distinctly the actual content of dirt than the sedimentation methods, where a considerable proportion of the dirt is drawn up into the cream during- the separation. The author uses an apparatus in which a disk of cotton is hold in a simple plate-shaped filter, over the vessel into which the milk is to be poured. The cotton disk is pressed into the filter by a glass cylinder, as is the case with the apparatus of Fliegel and Bernstein. At the present time such dirt testing- apparatus may be purchased from nearh- all dealers. For the household and for small amounts of milk certain filters are recom- mended like those in which the filling- funnel represents a bottom- less bottle, to the mouth of which a ring and a wire strainer con- taining a disk of cotton are attached, by means of a wire fastener. Henkel's control filter is also based on the principle of filtra- tion through cotton by which an angle-shaped segment of the filter- ing- disk remains free from dirt in order to control the purity of the milk. The same result is attained with other methods where the border of the filtering- disk remains free from dirt. At the places of official examination of milk distinction is made between slight, moderate, strong, very strong, and exception- ally strong- pollution, and the milk accordingly is judged as either clean or spoiled or even injurious to health. Market milk may be tested at receiving- stations either by drawing up samples from the bottom of the cans with the aid of long pipettes, or, as is customary in Munich, by pouring- the milk from the original can into another vessel The residue of the milk in the first case is taken as a sediment sample, while an average sample is taken from the mixed milk of the second container in order to make a quantitative estimation. Trommsdorff 's test is splendidly adapted to the detection of finely divided particles of dirt, the heavy particles being collected in a capillary tube. The methylene blue reductase test gives very good information relative to bacterial multiplication. A solution of methylene blue in water, serves as a reagent, consisting of 195 parts H2O and 5 parts saturated alcoholic methylene blue solution. The test is con- ducted by placing 20 c. c. of milk and 1 c. c. of methylene blue solution in a reagent glass at 40° C. and the time is determined in which the sky blue mixture becomes completely white. Milk which becomes white in less than 3 hours is already old. The age, how- ever, does not refer to the hours since its production, but means that the milk has "aged." Milk which is obtained in a dirty condition, Reductase Test. 217 lias not been cooled, and lias been transported in poorly cleaned cans, ages more rapidly than milk which has been properly treated. In making the test it is not necessary to cover the sample in the reagent glass with boiled oil or kerosene since there is no advantage in such a procedure. In the same way the ''reductase" which is recommended by commercial firms is of no advantage. Fresh milk from individual cows may be rapidly reduced owing to the large content of cells. Very valuable results are obtained with the reductase test when conducted in connection with the microscopic examination of the sediment. Frequently, in the testing of the centrifugal sediment, large numbers of bacteria are found not infrequently agglutinated in colonies, and the milk, in spite of the apparently high content^ of bacteria, has very little reducing power. This is an indication that the milk has been transported in uncleaned cans, but does not in itself prove decomposition. Microscopically in the residue of milk in the can are found milk souring bacteria, diplococci, streptococci, sarcines, besides oidia, coli, and rods. Such is also the case when the milk is obtained under dirty con- ditions, but is promptly delivered. The author determines the reduction property of the milk in the following manner : For each sample of milk 10 small tubes are used containing 1, 2, 3, 4, up to 10 drops of methylene blue solution, respectively. Into each tube 5 c. c. of milk is added. After i/4, i/o, 1, 2 hours, etc., observations are made as to what extent the milk has been reduced. This method, in spite of its apparently greater technique is nevertheless quite simple, as the constant watching of the sam- ples in order to determine the time is unnecessary. Both time and degree are determined. If, for instance, a milk is reduced in three hours to tube 8, then the formula will be: E3==8. Good milk reduces the first 2 tubes only after 2 to 3 hours ; fresh milk only after 10 to 12 hours. The Schardinger reduction of formalin methylene blue is of no value for the examination of market milk, as it also gives posi- tive results with fresh, raw, and boiled spoiled milk. In the same way it is not suited for examination of milk from individual cows. Miikj'wiiich does not decolorize in a few minutes at 60° C. by the Schardinger reagent, consisting of 190 parts water, 5 parts forma- lin and 5 parts saturated alcoholic methylene blue solution, may be from fresh cows, if the individual sample is taken from the total amount of milk of the cow (the first portion of milk at the milking does not reduce). The "Catalase" test is conducted by mixing together 15 c. c. of milk and 5 c. c. of 1% peroxide of hydrogen. The mixture is placed in a fermentation tube such as is used in the examination 218 Milk Inspection. of wine for the cletermination of sugar, and kept for 2 hours in an incubator, and after this period the amount of oxygen formed during this time is measured. It should not exceed more than about 1 c. c. Apparatuses which indicate the total amount of gas formed are more suitable; for instance, the "Catalaser" constructed by Henkel, or still Ijetter the one by Lobeck, in which a gas collecting and measuring tube is so attached above the bulb containing the milk that a line gas tube leading from the bulb to the upper part of the gas measuring apparatus allows the exit of the oxygen at the point. At the bottom of the gas collecting tube another tube opens, through which the water contained in the measuring tube is displaced by the liberated oxygen. Faitelowitz has constructed a shaking apparatus and a special ''Catalaser"; the shaking is supposed to expedite the liberation of the oxygen. Fresh milk evolves 1 to 2 c. c. of oxygen. Raw or pasteurized milk, spoiled through invasion of bacteria, produces considerably larger amounts of oxygen ; likewise milk rich in cellular elements as a result of physiological or pathological irritations of the udder, or mixed milk polluted by such secretions. The test is useless for the examination of market milk as to the presence of inflammations of the udder. High oxygen values of the catalase test in connection with low reductase values against the watery methylene blue, create a sus- picion of mastitis. High values by both methods indicate principally a spoiled condition, without differential diagnostic value relative to inflam- mation of the udder or bacterial decomposition. If the testing of the milk indicates that the product was pasteurized, sterilized or otherwise heated, and the catalase test is positive, the generation of oxygen proves the spoiled condition of the milk as a result of bacterial decomposition. AVitli fresh individual samples and samples from individual quarters the increased value of catalase proves the presence of mastitis, provided that no severe general diseases are present, and provided physiological irritating conditions are excluded. If all samples from the 4 quarters show increased catalase values, mas- titis may be present in all 4 quarters, or there may exist a general disease, as for instance tuberculosis or peritonitis. The test for amylase is only applicable to raw milk. Into each of ten test tubes are placed 10 c. c. of milk and . 1, . 2 up to 1 c. c. of a 1% solution of soluble starch which is dissolved through heat- ing. The series of tubes are placed for half an hour in the incu- bator. Then they are rapidly cooled, and to each is added 1 c. c.^ of a solution of iodine and iodide of potassium (1 of iodine, 2 of iodide of potassium, 300 of water). If the total amount of starch has been converted into sugar, the color of the mixture will be yellow. A grayish-yellow with a grayish-blue tinge indicates unchanged Fermentation Test. 219 residues of starch. Generally only tubes 1 and 2 but sometimes tube 3 become yellow. In the presence of large amounts of amylase, which usually runs parallel with the cellular contents, even the other tubes will appear yellow. An increased amount of amylase indicates physio- logical or pathological irritation of the udder. The raw condition of the milk is tested by the determination of peroxyclase. There are used either guaiac tinctures, the efficacy of which has been tested, or still better mixtures of guaiac-guaiacol with peroxide of hydrogen, for instance, resina guaiaci 10.0, guaiacol 10.0, 3% perhydrol quantum satis, absolute alcohol 80.0 (Schern). Eaw milk becomes blue, heated milk turns yellow. The Eoth- enfuss reagent is very reliable and is also recommended on account of its keeping qualities. First solution : 1 gm. paraphenylendiamin hydrochloride, 15 c. c. water. Second solution: 2 gm. crystallized guaiacol, 135 c. c. 96% alcohol. After dissolving, both are mixed together which results in a white or whitish-yellow reagent. For the execution of the test a 0.2% solution of peroxide of hydrogen is also essential. The milk to be tested is mixed wdth a few drops of a solution of peroxide of hydrogen, and then the reagent is added. Eaw milk at once be- comes intensely violet, while milk heated to over 80° C. remains white. The reaction is prettier and more distinct when instead^ of milk, milk serum is used, which is prepared in the following manner : 100 c. c. of milk is mixed with 6 to 12 c. c. of lead acetate solution, strongly shaken, and filtered through a folded filter. _At the plane of contact of the serum with the reagent, a violet ring appears if the milk is raw. If the reaction does not appear, and the lead-acetate-serum becomes turbid through boiling, the milk has been heated above 80° 0. and probably below the boiling temperature, which however was surely reached when on boiling of the serum no more albumen is precipitated. The fermentation test has less importance for the examination of milk to be consumed than of milk to be utilized for the manu- facture of cheese. The milk is filled into tall, wide test tubes and the latter are placed for 24 hours in the incubator at 38-40° C. Fresh milk does not curdle after 12 hours ; curdled milk should have a pure sour odor and taste, and at the same time a porcelain- like, scaly, coagulum with only a few gas bubbles. Many gas bubbles and fissures in the coagulum indicate the presence of aerogenes-coli and other bacteria which split up the milk sugar with the forma- tion of gas. A cheese-like curd develops as a result of the presence 220 Milk Inspection. of rennet producing species of bacteria, which are peptonizing bacteria, the presence of which is undesirable in drinking milk. Not infrequentl}'' the best milk produces imperfect cnrds. Milk from diseased animals curdles more poorly, with the formation of an abnormal curd. Still less important than the fermentation test is the rennet fermentation test which is used in cheese factories, where tlie milk, before being placed in the incubator is mixed with a solution of rennet. The resulting curd should be elongated and worm- shaped, contain few gas bubbles, and should not look twisted or pressed flat or swollen. The rennet inhibitory test recently recommended by Schern accomplishes other purposes than the rennet fermentation test. It tests the power of resistance of the milk against the effect of the rennet. For the test the following are necessary : 1. A number of test tubes. 2. Measuring pipettes of 10 c. c. capacity w^ith i/. c. c. gradua- tion and 1 c. c. pipettes divided in tenths and hundredths of c. c. graduations. 3. A water bath or an incubator with a number of perforated racks. ■i. An icebox. 5. 0.85% solution of common salt. 6. Solutions of rennet, the values of Mdiich are known and which remain constant (standard solutions of a known titer). In the performance of the test it is desired to ascertain : 1. Whether the titer of the solution of rennet still persists with sound milk. 2. Whether the milk to be tested by means of the rennet titer does not curdle, or how much more rennet is necessary to make the milk curdle. The samples are placed for 1 hour in the icebox, and then for 2 hours in the incubator, whereupon through pouring, a test is made as to which dilution of rennet has curdled the milk or whether the milk curdles at all up to the limit of titration. The test is not applicable to market milk, but only for fresh individual samples or samples of milk from individual quarters. Milk which utilizes considerably more of the rennet solution than the amount which corresponds with its titer is suspected of not being normal. The test is too laborious for practical control work and does not offer any advantages for the recognition of inflammation of the udder over the microscopical examination of the centrifugal sediment. The methods by which the milk is examined for the content of complement or amboceptor have the same shortcomings. They are of no importance in control work. The test for complement is as follows: Sedimentation Test. 99]^ 1. 5% suspension of washed blood corpuscles from guinea pigs or rabbits in 0.85% salt solution. 2. Hemolytic amboceptor of normal blood from cattle or goats heated to 56° C. 3. Milk. The milk is placed in tubes arranged in 2 rows of 5 tubes each in quantities of 1.0, 0.5, 0.25, 0.1 and 0.0 c. c. respectively. One row is inactivated by heating to 56° C. ; then in all the tubes the contents are brought up to 1 c. c. by adding salt solution. Fur- ther, to each tube are added 0.2 c. c. of the inactivated cattle or goat serum- and 0.5 or 1 c. c. of the blood-cell suspension. The rack is then placed for 2 hours in the incubator ( shaken frequent- ly) and placed over night in the icebox. Hemolysis occurs in physiological and pathological irritations of the udder. The test for amboceptors is carried out in a similar manner, with the exception that the milk in all the tubes is inactivated, and into the tubes of one row complement is added in quantities deter- mined by titration. In the test for amboceptor and complement the various sub- stances which enter into the test should be controlled for possible errors. Trommsdorff's method is best adapted to determining the quantity of centrifugal sediment in milk. The tubes which terminate at the bottom in a graduated capil- lary tube (Trommsdorff's tubes) are tilled with "lO c. c. of milk and centrifugalized for several minutes in a centrifuge at about 1500 to 2000 revolutions per minute. All elements having the greatest specific gravity collect in the capillary tube. All sediment of a yellow, clay or reddish color which does not consist of cow manure and which is sharply separated from the layer of skimmed milk irrespective of its quantity, should be sus- pected as being due to an inflammation of the udder, since larger quantities of tissue cells are thrown off only in pathological or physiological irritations of the udder. In market milk this test gives uncertain results, but in individual samples and in samples of individual quarters the results may be well utilized. If the centrifugalized sediment is not distinctly separated from the skimmed milk, and the scale is therefore not readable, then the tube is filled with clear, cool water and the capillary end is turned up- ward. The water having a lower specific gravity, penetrates into the capillary tube up to the border of the sediment. For testing of individual quarters the author recommends the sedimentation test in tubes with chisel shaped ends and with funnel shaped mouths. The milk is drawn directly into these tubes from the quarter, after discarding the first milkl The four sam- ples from a cow are allowed to stand for about 8 hours and then 222 Milk Inspection. examined for the presence of sediment. Sediment, which appar- ently does not consist of cow manure, indicates an inflannnation of the ndder, provided the colostral stage has passed and the animal is not close to the end of its lactation period. The sedimentation test may be and should be undertaken by every dairyman. Its application is easy. Milk which separates recognizable quantities of sediment should not be sold or used as food for man. In the scientific examination of market milk and of individual samples, the microscopical study of the milk can no longer be neglected. In Munich the sediment of the milk is examined micro- scopically. A platinum-wire loop (the wire must be completely folded) is passed into the depth of the capillary tubes and without turning, the sediment is lifted out by pressing the wire against one side and drawing out a loopful. In the procedure the contact of the wire with the milk or cream of the tube should be prevented. The smear is made in the usual manner; the best way is to place the loop of the wire on the slide and by lifting it up a somewhat thicker droplet remains at the place of contact. This may be spread over the slide and is especially well adajDted for microscop- ical examination. The smear is dried in the air, fixed by heat or alcohol and stained by the ordinary methods. For staining, the author recom- mends a thionin solution which consists of y^ concentrated alco- holic thionin solution and -/^ distilled water. In market milk are observed many plant fibers and plant cells, plant hairs, staph3do- cocci united into colonies, colon varieties, acid fast rods, sarcina, blackleg and anthrax-like bacteria with or without spores, if the milk was produced under dirty conditions. If such a milk sample is older, not infrequently mycelial threads germinate from the mould spores. If the milk is bad and was transported in dirty cans, besides the colon-like bacteria, staphylococci, diplococci, streptococci, sarcina, oidia and cheese bacteria may be seen. If the milk is at the point of decomposition, diplococci and streptococci dominate the field. A diagnosis that milk is mixed with the secretion of a cow affected with streptococcic mastitis is only permissible, when besides the cells from the animal body (leucocytes, epithelia under- going fatty degeneration, erythocytes, etc.), the animal forms of streptococci are demonstrated. The positive finding is decisive but the negative does not exclude. Market milk which, besides numerous leucocytes, shows no animal streptococci, only creates a suspicion that the secretion is from cows with affected udders. The increased amount of horny epithelia of the teats in sam- ples of individual cows indicates the fresh milking period of the animal. Table V Sediment of dirty market milk which contains the secretions of cows with affected udders, and which has been transported in filthy cans. Thionin stain. 1 X 1000. Ernst, Milk Bygiene. Microscopic Examination. 223 Tlie presence of epithelial nests from the cistern suggests a catarrh of the cistern. An increased number of leucocytes and colostral cells indicates an irritation of the parenchyma. The causes of the irritations are often manifested by the presence of diplococci in phagocytes or isolated diplococci and frequently atypical short forms, or the typical animal forms of the Streptococcus longus or 8. hrevis are recognized. Even atypical forms of diplococci and streptococci, when pres- ent in such forms in milk only a few hours old, are an indication of streptococcic mastitis (care must be exercised in the absence of experience and if the evidence is to be used in court). In pyobacillosis the typical, short, slender bacilli are found which simulate in their morphology the bacilli which frequently cover the horny cells of the outside skin of the teats. In samples from individual cows, the microscopical examina- tion may establish the diagnosis of "tuberculosis of the udder," when the specific organisms are found enclosed in leucocytes or curds. The staining is carried out with hot carbol-fuchsin solution (1 part fuchsin to 10 parts of absolute alcohol, and 90 parts of a 5% carbolic acid solution). By decolorizing with 33% aqueous nitric acid and subsequent washing with alcohol the non-acid fast rods and the body cells are decolorized. The decolorized elements may be given a blue contrast stain, against the red tubercle bacilli by subsequent staining of the preparation with aqueous methylene blue or methylene blue anilin water. In order to avoid the dragging of too many tubercle bacilli into the cream by the cells and fat globules, for the microscopical examinations, the milk should be first homogenized. The following methods are the simplest : a. Knut Arnell recommends mixing 25 c. c. of milk with 2 c. c. of concentrated ammonia and 100 c. c. of a mixture of equal parts of ether and petroleum ether in a sedimentation cylinder, which runs to a point at the bottom and at its lower part is supplied with a stopcock. This is frequently shaken and then allowed to stand for the separation. The ammonia-casein solution is then drawn off, the remaining content is centrifugalized and the sediment examined. b. Thorner recommends mixing 20 c. c. of milk with 1 c. c. of 50% potassium hydrate. This is heated in boiling water until in complete solution and then centrifugalized. c. Biedert recommends adding 10 c. c. of milk to 1000 c. c. of Vv^ater containing 4 to 8 drops of sodium hydrate solution. This is shaken, boiled and then set away for sedimentation. If after staining, the slender rods which remain red are pres- ent only in small numbers, or if the sediment shows no cells which indicate an inflammation of the udder, or if the examined milk proves to be a dirty market milk, then the diagnosis must be estab- 224 Milk Inspection. lislied by incubation, since the milk may contain from the feed, etc., only harmless, acid fast rods. The inoculation is made into guinea pigs by injecting- them either subcutaneously or intramuscularly in the hind leg with either 1 c. c. of the full milk, or better, with the centrifugal sediment mixed with a snuill amount of the skimmed milk with or without cream. The sediment should be obtained by using rapidly revolving elec- tric centrifuges. If the samples have to be transported long distances, they should be mixed before transportation, and if possible immediately after drawing the milk, with 1:2000 to 1:3000 of formalin (boric acid 1 :50 or 1 :100 is also satisfactory). The tubercle bacilli which are protected by a waxy capsule from the effects of the preserving- agents, are not harmed b}^ such preservation to such an extent that they could no longer be demonstrated b}' inoculations. For each milk injection at least two guinea pigs should be used, since occasionally the inoculated animals die as a result of some other intercurrent disease. In the presence of tubercle bacilli the regional lymph glands swell after several days or a few weeks. Such animals, if they do not die before, should be killed on the appearance of these swellings, and they as w^ell as those which died should be examined for the presence of tuberculosis. The surviving guinea pigs should be kept under observation for several months. In examining entire herds, it is advisable to group the cows; for instance, five animals may form one group and the mixed milk of this group should be separately inoculated. The counting of bacteria is carried out either by the ordinary method of plating- which is made with certain dilutions of milk on agar or gelatin or also by direct counting in smears which should be prepared according to Olav Skar. The method consists in mixing in a reagent glass 4/10 c. c. of a 2% solution of carbol-methylene blue (for animal cells and bac- teria) and 3.5 c. c. carbol-methylene blue, with 0.5 c. c. of a S% sodium hydrate solution (for bacteria alone). Then 10 c. c. of milk is added to the stain with a pipette and heated for about 10 minutes at 70° C. Of the mixture, 1/50 of a c. c. is uniformly smeared upon a certain sized field (24 X 20 m. m.) of a special slide, and dried in the air. AVithout any further fixation or other treatment, a number of fields in the smear are counted in their entire length and width, and with the aid of the ocular micrometer the number of bacteria in the counted fields is calculated to the c. c. of milk, ac- cording to the standard given below. When chains and clumps are encountered each bacillus must be counted. The ocular micrometer of Zeiss in Jena as applied by Skar has a determined field capacity so that one bacterium, with the above technique and with a certain tube length of the microscopCj viewed with a 1/12 oil immersion Coimtina;- Bacteria. 225 objective, indicates the following number of bacteria for the various fields which are designated by letters : In 1^ of square a = 40,000,000 per c. c. of milk In 1/2 of square a = 20,000,000 per c. c. of milk In total square a = 10,000,000 per c. c. of milk In 1/4 of square b = 8,000,000 per c. c. of milk In 1/0 of square b = 4,000,000 per c. c. of milk In total square b = 2,000,000 per c. c. of milk In circle c = 1,000,000 per c. c. of milk In total field of observation = 800,000 per c. c. of milk The total number of bacteria found in all the counted fields is multiplied by the relative number corresponding to the field of the size that was counted and divided by the number of counted fields. If, for instance, in 20 ocular fields of size "a" Skar found the number to be 150 bacteria, then these figures give : 150X10,000,000 ^150x500,000=75,000,000 per c. c. of milk. Skar always found many more bacteria by this method than were found by the plate method (2 to 70 times as many). The direct counting is more rapid and more accurate than the plate counting method. As already mentioned, for practical control work the counting of bacteria may be omitted. In this work the reductase test offers a quicker determination of the spoiled condition of the milk. For special examinations the following methods are recom- mended: For determining age and decomposition the reductase test and periodically repeated acid tests, besides the microscopical examination of the sediment, should be applied. For determining decomposition of pasteurized milk, the per- oxydase test, in combination with the reductase test, and, at times also the catalase test and microscopic examination of the sediment, should be used. For the judgment of dirty milk, the determination and esti- mation of the dirt content, the reductase test, periodical acid test and microscopic examination of the sediment should be made. Inflammation of the Udder. (a) Market milk: 1. Determination of the quantity and appearance of the centrifugal slime. 2. Microscopic examination of the sediment _ for parenchyma cells and the presence of animal forms of streptococci. 3. In tuberculosis: Inoculate. (b) Individual samples: 1. Trommsdorff test. 15 226 ^lilk Inspection. 2. Microscopical test of the sediment and examina- tion as to the presence of parenchyma cells and diplococci, streptococci of the short and long forms, particularly the animal types or the pyogenes or tubercnlosis bacillus. 3. If necessary the catalase test or examination for amylase. (c) Samples from individual quarters: 1. Trommsdorff or sediment tests. 2. Microscopy and, if necessarj^ inoculation. 3. Catalase or amylase test. In examinations for milk defects, the following tests are reconnnended : 1. Tests with the senses. 2. Shaking test (soapy milk). 3. Eeductase test (frequently the reduction appears very slowly, for instance, with tallowy and soapy milk). 4. Acid tests. 5. Historical consideration of the conditions of stables, pasturage, litter, feed and water, preparation of milk. 6. Fermentation test. 7. Cultivation of bacteria from the milk, feed, pastures, etc., at temperatures at which the defects in the milk appeared. 8. Examination of cultures in sterilized milk. (a) Pure cultures, (b) Special mixtures of colonies. The veterinarian should also be able to conduct the routine examination methods usually conducted in the milk laboratory and the preliminary chemical tests for adulteration, provided food chemists are not available in such localities. It would lead too far to mention at this time all the methods which may be applied in suspected adulterations. Only a few methods will be described, particularly those which are employed at the official milk labora- tory in Munich. Determination of the specific gravity of milk. It is best to test the milk for its specific gravity after heating it to 15° C. or in the neighborhood of this temperature. The milk is shaken up and it is advisable to make the test in suspended cylinders with the aid of an aerometer and a thermometer. It is not advisable to use aerometers into which thermometers are fused. The lac- todensimeter used for milk must be officially tested. The specific gravity of milk varies in accordance with its contents in dis- solved, suspended and emulsified ingredients. The lactodensimeter is slowly immersed in the milk and should not touch the walls of the cylinder. After the instrument has come to a rest, the place at which the level of the fluid touches Specific Gravity. 227 the lactodensimeter is read. The numbers on the lactodensmieter indicate the second, third and fourth decimals of tlie specific gravity. For each additional degree above 15° C, 0.2 should be added to the reading of the lactodensimeter, and for each degree below 15° C, 0.2 should be deducted. In this way the corrected readings of the lactodensimeter are obtained, before which must be placed 1.0 in order to obtain the specific gravity. The Munich lactodensimeter which is adjusted to a temperature of 15° C. is recommended for general use. The specific gravity of the milk may also be determined by the so-called pyknometer. This method is suitable for small quantities of milk. A third method of determination of the specific gravity is Westphal's modification of Mohr's balance. This is so constructed that the lever arm of the balance from its zero point (the axis of the balance) is provided with 9 notches at such dis- tances, that a rider suspended on it indicates from 1 to 10 times its weight, depending upon whether it is pushed towards the end of the arm or towards its axis. Point 10 at the end of the arm is provided with a loop. A weight A, suspended in the loop of point 1, acts on point 1 only as a weight of A/10 at point 10. The weights A, Ai, and A2, may be mutually interchanged and indicate the integer and the first decimal figure of the specific gravity, depending upon whether they are suspended in the loop or in the notches. The weight B=l/10 of A, and indicates when in the notches 1/100, while C represents 1/10 of B and when in the notches indicates the 1/1000 of the specific gravity. ^ By shifting the weight C between two notches the fourth decimal point may also be approximately established. Hydrometers made of glass and the use of separate ther- mometers are recommended. The specific gravity of market milk varies between 1,029 to about 1,033. The increased or decreased specific gravity, as compared with the average specific gravity of the milk of the respective locality, can at the most only be suspected as being caused by dilution with water or by removal of the cream. In case of double adulteration the specific gravity may remain normal. After the specific gravity has been determined, the fat content is established by one of the ordinary empiric methods. Gerber's acidbutyrometric method is employed at the milk control station of Munich. The following apparatus is needed for this method. 1. Centrifuge. 2. Butyrometer (round butyrometer, flat butyrometer, ** optical" butyrometer) which is a milk receptacle, ending in a graduated tube into which are poured sulphuric acid, amyl alcohol and milk, and which is closed by means of a rubber stopper. 3. A 10 c. c. pipette or an automatic measure adjusted for OOQ Milk Inspection. 10 c. c, for measuring the sulphuric acid, an 11 c. c. pipette for milk and a 1 c. c. pipette or a corresponding automatic measure for amvl alcohol. 4. ' Commercial sulphuric acid of a specific gravity of 1,820 to 1,825 (at 15° C.)- 5. Amyl alcohol with a specific gravitv of about 0.815 (at' 15° C.) and a boiling point of 128 to 130° C. 6. Shaking a))i)aratus with a protective cover. 7. Water bath. First sulphuric acid (10 c. c.) is poured into the butyrometer, then 11 c. c. of milk, and finally 1 c. c. of amyl alcohol. The tube is closed with a rubl)er stopper and then roughly shaken. Through mixing, the contents become greatly heated. After the disappear- ance of all flakes and after the tube has been held for several minutes at 65° C, it is centrifugalized. Following the centrifu- galization it is again heated at 65° C. and then quickly read. In order to avoid the more, or less dangerous handling of sulphuric acid, Sichler's "sinacid" and Gerber's "sal" methods have recently been inaugurated, in which alkaline salt solutions are employed instead of the sulphuric acid. The results are ap- proximately the same as in the acid butyrometers. [In the United States the most popular method for determin- ing the amount of fat in milk is by the Babcock test. If carefully applied the results can be relied upon without question. In the application of this test sulphuric acid is used to free the fat globules by dissolving the casein. Then by proper cen- trifuging the fat is collected in such a manner that it may be readily measured. For the execution of the test special test bottles are provided. A definite amount of milk (17.6 c. c.) is placed into a test-bottle to which 17.5 c. c. of commercial sulphuric acid of a specific gravity of 1.82 to 1.85 is added by means of a pipette, burette or other measuring apparatus. The contents are then thoroughly and carefully mixed, as a result of which the fluid turns brown and becomes somewhat heated. The bottles are then placed into a centrifuge which is specially constructed for this purpose, and centrifuged for 5 minutes at 900 to 1,200 revolutions per minute. After removing the bottles from the centrifuge they are filled with hot water up to the lower part of the neck and they are again centrifuged for two minutes. A sufficient amount of hot water is now added to float the melted fat into the neck of the bottle which is provided with a graduated scale, and the centrifuging is repeated for one minute. The volume of fat can be easily read from the graduated portion of the bottle, and this reading should be done while the neck of the bottle is still hot. — Trans.] The fat content of the milk fluctuates between wide limits. The total solids and the fat-free solids may be established with Calculation of Milk Solids. 229 the aid of the specific gravity and the obtained fat content. d^percentage of solids^i/o X f + 2.665 X — " In this equation f==fat content and s=specific gravity. Fleischmann has prepared two tables for the values of y2Xf and for the value of 2,665 X — ' for the specific gravity s from 1,028 to 1,0369 and for 2.5% to 5.49% of fat, so that through simple addition of the determined values, the respective content of solids can be established. Still simpler is the calculation of the solids by Ackermann's ''slicle-ruler," which consists of two disks united at the -turning point and which slide against each other. The larger of these contains the numbers for the solids and fat contents, while the smaller has the numbers for the specific gravity. By turning the small disk the established specific gravity number and the fat con- tent number of the tested sample are placed opposite each other. An indicator fastened to the inside disk points to the amount of the total solids. The amount of fat-free solids is obtained by subtracting the percentage of fat from the percentage of total solids. This is an important factor in suspected cases of adulteration. Marked dif- ferences are the result of artificial influences but in individual samples the difference may be due to natural fluctuations. Milk with a high fat content has as a rule more fat-free solids. The milk of cows of the highlands has more fat-free solids than the milk of cows from the lowlands. According to Fleischmann, it should be noted that the fluctua- tions of the different values indicated herein, vary in the different milking periods as compared with the annual average. These fluctuations may amount to : 10% in the lactodensimeter reading (specific gravity). 30% in the fat content. 14% in the total solids. 10% in the fat-free solids. According to Fleischmann, the fat-free solids do not fall below 7.9%, and the specific gravity of the total solid matter (m) which may be determined by the following formula : _ s X d ^~ s X d— 100 s + 100 exceeds only exceptionally 1.4 and is usually 1.31 to 1.36. Excepting the milk of individual cows or that of a few cows, according to the agreement of German food chemists, the presence of adulteration is established as follows : 1. Adulteration with water when the specific gravity of the 230 ^^''1^ liispc'C'tiou. milk is below 1.028, that of the serum ))elo\v 1.026 and the content of fat-free solids falls considerably below 8%. 2. Cream has been removed from the milk when in the pres- ence of an increased specific gravity of the milk and normal specific gravity of the serum or normal content of fat-free solids, the per- centag'e of fat content of the milk solids falls considerably below 20% ; that is, the speeilic gravity of the latter is increased consider- ably above 1.4, 3. Adulteration with water together with removal of some of the cream may be suspected when with a normal specific gravity of the milk, that of the serum falls below 1.026, and with a dimin- ished amount of all the ingredients of the milk the fat content of the solids falls considerably below 20% ; that is, the specific gravity of the latter is increased considerably over 1.4. The percentage of fat contents of the solids is obtained from the following formula : f X 100. d At the same time it must be remembered that no definite figures of limitation should exist and that only comparative figures are convincing. The sample for comparative tests may be ob- tained by informing the manager of the dairy or the responsible producer that the milk is suspected of being watered, and he is directed to devote special attention to the milk production and its subsequent handling. If following this procedure the milk becomes notably changed the test may be considered as comparative, pro- vided that it is not preferred to undertake immediately an official comparative test. This must be done as quickly as possible, and not later than the third day after the suspicion has been estab- lished. According to Herz the following formulas apply in the calculation of adulterations : w = the added water contained in 100 parts of milk. V = the added water to 100 parts of milk. p = the fat removed from 100 parts of milk. ri = the fat-free solids of the stable sample. ro = the fat-free solids of the suspected market sample. f, = fat contents of the stable sample. fo = fat contents of the suspected market sample. M = 100 — w, the amount of original undiluted milk contained in 100 parts of watered milk. 100 X (r, — r,) w 100 X (r, — r,) p =. f,— f, + 1*2 f. X (f>— f^) 100 Detection of Adulteration. 231 Finally in combined adulteration we have ^100 ^ J X rf _M X f, — 100 f.l L M J P — fi- 100 other formulas according to Vogel are : The addition of water in per cent = 1^ X 100 — 100 The removed amount of fat in per cent = 100 X ^ — " ±1 or according to Bohmlander : V ^ — X w — W, in which w = the contents of water in the r2 suspected sample and W = the contents of water of the unsuspected sample, and E = 100 I 1— i^-m) (E = removed fat in % of the fat content) The establishment of the suspicion and the establishment of the amount of adulteration are greatly supported by the examina- tion of the milk serum free from proteins, which contains the sub- stances dissolved in the milk, the content of which is subject to only the slightest variations. The examination is carried out 1. Through the specific gravity, or 2. Through refractometric observations. It is best to prepare the serum according to Ackermann by the addition of . 25 c. c. of a solution of calcium chloride of a specific gravity of 1 . 1375, to 30 c. c. of milk, which mixture is thoroughly shaken in a reagent tube. The tube is closed with a rubber stopper through which a glass tube is inserted as a reflux condenser, and it is then heated to boiling for 15 minutes. The tubes are then rinsed in cold water and the condensation water of the cool- ing tube is united with the serum by slow, repeated and careful shaking. With milk which is in a state of decomposition, the milk serum turns cloudy and the values of refraction are also changed. Milk from affected udders which is considerably changed, fre- quently curdles only following the addition of double quantities of calcium chloride solution. Differences in the refraction values of 2.4 to 2.50 indicate about a 10% adulteration. The removal of cream does not change the refraction value of the milk. For refraction the serum prepared according to Ackermann does not have to be filtered, but this should be done for the deter- Milk Inspection. iiiination of the specific gravity, which is usually 1.026 to 1.027. In applying this method it may become necessary to use larger amounts of serum. Differences of about 0.0025 in the specific gravity indicate mixing with about 10% of water. The positive demonstration of nitrates in milk is always a proof that the milk has been watered and with water that should be considered as objectionable as drinking water, or that has been used for the rinsing of the milk containers, and wliich according to its quality must be considered as impure. Milk which gives the nitrate reaction should therefore be considered not only as adul- terated but also as being spoiled in the sense of the pure food law and even as injurious to health. The nitrate test may become of great importance for the conviction of certain persons, when for instance the water of the well at the barn contains nitrates, while the one at the farmhouse has no nitrates and vice versa. According to Rothenfusser the nitrate test is a su1)stantiating proof of great importance. Milk samples contaminated with manure and litter do not give the nitrate test. Nitrates and nitrites do not occur in milk of animals fed and cared for in the usual manner on the farm. Rothenfusser ascer- tained that the unavoidable residue of water used in rinsing the milk containers represents only a tenth or a twentieth part of the amount of water, which is necessary to make a 1% addition and that the residue of water retained in the rinsed vessel must possess the qualities of ditch water in order to be capable of adding to the milk a demonstrable amount of nitrates. According to Rothen- fusser the test may be carried out to the best advantage, by placing into small, flat, white porcelain vessels 2 c. c. of pure sulphuric acid of a specific gravity of 1.84, over which a small amount of crystallized diphenylamin is sprinkled from a sprinkling cylinder (a reagent tube with, a perforated cork stopper, into which a short glass tube of about 3 mm. inside diameter is inserted). Then a small quantity of chloride of calcium serum of the milk to be examined is allowed to flow in from the edges of the vessel. The appearance of the grayish-blue clouds and stripes in the fluid indicates the presence of nitric acid in the milk. Chapter XI. FUNDAMENTAL PRINCIPLES OF LEGISLATIVE MILK CONTROL. The practical inaiigiiration of milk hygiene is, of course, only possible where proper laws and ordinances are at our command for the accomplishment of the result. The laws, regulations and ordinances of the various states and municipalities promulgated for the purpose of controlling the milk supply lack uniformity in many of their essential requirements, and it is apparent that these measures were drafted to meet the conditions prevailing in the different localities. Furthermore, a general federal control of the milk supply cannot be considered practicable, except possibly in so far as interstate shipments of milk may be involved. The individual states may foster the interests of public health by the inauguration of such legislative measures as will assure a wholesome and clean milk supply for the different municipalities within the state, particularly when the necessity prevails for the shipment of milk from long distances to a city. For this purpose the state might well be divided into districts, supervised by com- petent inspectors who would primarily inspect the cattle and stables, the methods of producing the milk and its transportation. Such inspectors could also be of splendid service in the control and possible eradication of contagious diseases which not only may have an effect on milk production, but which are also of im- portance to animal industry in general. The largest proportion of actual control work, however, will have to be carried out by the different municipalities, where, with proper ordinances and with competent inspectors and laboratory officials, an efficient control could be maintained which would assure a wholesome milk supply to the consumers. It is apparent that such ordinances must be drafted to meet the local conditions, which would depend upon the dairying industry in that section, the num- ber of the population and the feelings of the people. While there exists no uniformity in the regulations govern- ing milk inspection and milk hygiene in general in the different parts of the United States, the necessity for at least a uniform standard has been met in a most satisfactory manner. After con- siderable agitation medical milk commissions were organized in 233 o*^^ Principles of Leoislative l\rilk roiihol. varioiTS cities of the United States for the purpose of estahlishino- milk standards and also of ohtainini^- such legislation as would assure clean and wholesome milk to the connnunities. The orgaui- zation of milk connnissions in this country was undoubtedly an important step towards the improvement of the quality of milk, and only by the concerted work of these and similar organizations can the country at large l)e assured of a proper milk supply. It is regrett-cible that milk, the most important food, is not considered by the laity of sufficient importance to l)e subjected to the most rigid control, especially since it constitutes the principal, and in early life the only food of children. The second report of the Commission on Milk Standards, ap- pointed by the New York Milk Committee, embodies the principles for a wholesome milk supply and would serve well as a basis for the formulation of effective ordinances. Therefore it is deemed advisable to reproduce these principles from the Public Health Eeports of August 22, 1913, United States Public Health Service. Need of Milk Control. Proper milk standards, while they are essential to efficient milk control by public health authorities and have as their object the protection of the milk consumer, are also necessary for the ultimate well-being of the milk industry itself. Public confidence is an asset of the highest value in the milk business. The milk producer is interested in proper standards for milk, since these contribute to the control of bovine tuberculosis and other cattle diseases and distinguish between the good producer and the bad producer. The milk dealer is immediately classified by milk standards, either into a seller of first-class milk or a seller of second-class milk, and such distinction gives to the seller of first- class milk the commercial rewards which he deserves, while it inflicts just penalties on the seller of second-class milk. For milk consumers, the setting of definite standards accompanied by proper labeling makes it possible to know the character of the milk which is purchased and to distinguish good milk from 1iad milk. In the matter of public health administration, standards are absolutely necessary to furnish definitions around which the rules and regula- tions of city health departments can be drawn, and the milk supply efficiently controlled. Public Health Authorities. Wliile public health authorities must necessarily see that the source of supply and the chemical composition should correspond with established definitions of milk as a food, their most important duty is to prevent the transmission of disease through milk. This means the control of infantile diarrhea, typhoid fever, tuberculosis, Disease Transmitted Through Milk. 235 diphtheria, scarlet fever, septic throat infections, and other infec- tious diseases in so far as they are carried by milk. Septic Sore Throat. Septic sore throat deserves special mention because of the frequency in recent years with which outbreaks of this disease have been traced to milk supplies. The suggestion has been made that the infection of the milk is due to udder infection of the cow and on the other hand it has been suggested that it is due to con- tact with infected persons. The uncertainty can not be dispelled until cases of septic sore throat are regularly reported and tabu- lated by public health authorities. The commission therefore rec- ommends that public health authorities make septic sore throat a reportable disease. Economic Problem. The commission recognizes the magnitude of the milk industry, and that the improvement of milk supplies is primarily an eco- nomic problem. The success achieved by the experiment in milk production, which has been carried out on a very large scale by the New York Dairy Demonstration Co., is an illustration of the fact that an extra price or premium paid to the producer for cleanliness and care will bring results far more quickly and certainly than instructions or official inspection. But while the basic problem is economic, and must eventually be solved by com- merce, public health authorities must show the way and must estab- lish standards and regulations in the interest of consumers, the value of which even the consumers themselves often fail to ap- preciate. Legal Requirements. A prime requisite of effectiveness is that local milk laws shall not exceed sanitary limitations. The commission has not entered into a discussion of fimdamental state laws, but it recommends that state laws be amended wherever necessary in order that every municipality may have the legal right to adopt whatever ordinances it sees fit for the improvement of the milk supply. The commission advocates that local health laws be carefully drawn Avitli regard to their legality under the general laws of the localities to which they apply, since a decision against a milk law in one locality is liable to be used as a precedent against milk laws elsewhere. Standard Rules and Regulations. The commission has drawn up a set of standard rules and regulations for the control of milk. These are the result of a study of the printed rules and regulations of the cities of the United States and of foreign countries and represent an immense amount o;](^ Principles of Legislative Milk Control. of work on the part of the special committee of the commission to wliich the task was assii>ned. Some communities are in a posi- tion to adojit all of these rules and reunlations at the present time, while other connnniiities will be obliged to adopt a few rules at a time as public sentiment and local conditions warrant. It is real- ized that some of the rules may have to be modified to meet local eouditious. It seems wise to the commission to divide the regula- tions into two parts: First, requirements, under which head are set down those provisions which are so fundamentally necessary that no community is justified in compromising* on them ; second, reconnnendations, under which head are set down provisions which are necessary for a good milk supply, but on which there can be a certain amount of latitude for compromise by those communi- ties in which public sentiment is not ready to support more than a moderate degree of protection of human life. Administrative Equipment. Another prime requisite is that the administrative depart- ments shall be adequately equipped with men, money, and labora- tory facilities. In smaller communities cooperation between local boards of health to the extent of exchanging reports would elimi- nate much duplication. Where a community can not maintain a laboratory it can enter into laboratory arrangements with other communities, and several can combine in the use of a common laboratory. Much of the expense of tuberculin testing can be borne 1)y the national and state governments. The commission is of the opinion that results can not be expected from laws where there is not sufficient appropriation and where there is no ma- chinery for their enforcement. On this subject the commission passed a resolution as follows : Whereas the appropriations g^enerally made for the purposes of carrying on laboratory analyses of milk are now in most eases entirely inadequate: Therefore be it liC-'ioli-cd, That this commission recommends for the consideration of the authorities concerned an appropriation of funds commensurate with the importance of lalioratory methods, which are of paramount importance in the hygienic control of the milk supply. Grading of Milk. There is no escape from the conclusion that milk must be graded and sold on grade, just as wheat, corn, cotton, beef, and other products are graded. The milk merchant must judge of the food value and also of the sanitary character of the commodity in which he deals. The high-grade product must get a better price than at present. The low-grade product must bring less. In separating milk into grades and classes the commission has endeavored to make its classification as simple as possible and at the same time to distinguish between milks which are essentially different in sanitarv character. Pasteurization of Milk. 237 In general two great classes of milk are recognized, namely, raw milk and pasteurized milk. Under these general classes there are different grades, as indicated in the report of the committee on classification. Pasteurization. While the process of pasteurization is a matter which has at- tracted a great deal of attention in recent years, the commission has not entered into any discussion of its merits or demerits, but has given it recognition in its classification as a process necessary for the treatment of milk which is not otherwise protected against infection. The commission thinks that pasteurization is necessary for all milk at all times, excepting grade A, raw milk. The majority of the commissioners voted in favor of the pasteurization of all milk, including grade A, raw milk. Since this was not unanimous the commission recommends that the pasteurization of grade A, raw milk, be optional. The process of pasteurization should be under official super- vision. The supervision should consist of a personal inspection by the milk inspector. The inspections shall be as frequent as possible. Automatic temperature regulators and recording ther- mometers should be required and the efficiency of the process frequently determined by laboratory testing. Pasteurizing Temperatures. The destruction of the chemical constituents of milk by heat occurs at higher temperatures than those necessary for the destruc- tion of the bacteria of infectious diseases transmissible by milk. The commission passed a resolution regarding the temperature of pasteurization as follows : That pasteurization of milk should be between the limits of 140° F. and 155° F. At 140° F. the minimum exposure should be 20 minutes. For every degree above 140° F. the time may be reduced by 1 minute. In no case should the exposure be for less than 5 minutes. In order to allow a margin of safety under commercial condi- tions the commission recommends that the minimum temperature during the period of holding should be made 145° F. and the hold- ing time 30 minutes. Pasteurization in bulk when properly carried out has proven satisfactory, but pasteurization in the final con- tainer is preferable. It is the sense of the commission that pasteurization in the final container should be encouraged. 238 Principles of Legislative Milk Control. Labeling and Dating of Milk. The commission voted that all milk should be labeled and marked with the grade in which it is to be sold. In dating- milk nniform methods shonld be adopted for all grades of both raw milk and pastenrized milk, both nsing the day of the week or both nsing the day of the month. All milk shonld be dated nniformly with the date of delivery to the consumer. Raw milk should not be dated with the date of production, while pasteurized milk is dated with the date of pasteurization, since this places certified milk at a disadvantage 1)y making it possible for pasteurized milk of a lower grade to carry a later date. The stamping on the label of the day of the week is sufficient for dating. Bacteria. The subject of bacteria in milk received more attention than any other matter brought before the commission. The commission recognizes that bacteria in milk in the majority of instances indicate dirt, or lack of refrigeration, or age, while in the minority of instances the bacteria of disease may be present. The routine laboratory methods for examining milk have as their purpose only the control over dirt, refrigeration, and age, and it is a rare thing for a laboratory to undertake the examination of milk for the bacteria of disease because of the extreme difficulties in detecting them. The more efficacious method of protecting milk from infec- tion by the bacteria of human contagion is by medical, veterinary, and sanitary inspection, and by pasteurization. Milk with a high bacteria count is not necessarily harmful, but when used as a food, particularly for children, is a hazard too great to be warranted. Milk with a high bacteria count, therefore, should be condemned. Milks wdtli small numbers of bacteria are presumed to be whole- some, unless there is reasonable ground for suspecting that they have been exposed to contagion. Bacterial Standards. The commission recognizes the difficulty in interpreting bacteria counts. At times misleading conclusions have been drawn from such counts. In establishing the bacterial standards for a city it is always necessary to take into consideration the necessary age of the milk and in lesser measure the distance hauled and methods employed in its hauling. It will always be possible for a community which consumes milk produced on its own premises, or within 12 hours of its production, to insist upon and maintain a lower bacterial standard than can one where the milk is hauled Bacterial Standards. • 239 many miles into town in a wagon, to be consumed within 24 hours after it is produced. In like manner this second type of city can always maintain a lower bacterial standard than a city where the general milk supply is hauled by railroad long distances and is several days old when consumed. In drawing conclusions as to the relative efficacy of milk control in cities comparisons must be made between cities of the same class. The commission deems it ot the utmost importance that some standard method should be adopted for estimating and comparing the bacterial character of milks, since by this means only is it possible to grade and classify milks and to enforce bacterial standards. There is much diversity of opinion as to the best method of valuing bacteria counts. The average of a series gives results which are misleading about as frequently as otherwise. In the average a single high figure may unduly overbalance a large number of exceedingly low counts. There are objections to the use of the ''median" or middle number when the counts are ar- ranged in order of size, for the reason that the middle figure does not distinguish between two groups in one of which there may be some very high counts above the median and in the other of which there are none. The method of dividing results into groups as recommended by the American Public Health Association, while a step in the right direction, is cumbersome and does not clearly indicate whether or not a milk conforms to a given bacterial standard. The commission passed a resolution at its last meeting regard- ing the number of bacterial tests necessary to determine the grade into which a milk falls, as follows : That the grade into which a milk falls shall be determined baeteriologically by at least five consecutive bacteria counts taken over a period of not less than one week nor more than one month, and at least 80 per cent (four out of five) must fall below the limit set for the grade for which the classification is desired. Laboratory Examinations for Bacteria. On the subject of laboratory examinations of milk for bacteria the commission passed the following resolutions : 1. That the interests of public health demand that the control of milk supplies, both as to production and distribution, shall include regular laboratory examinations of milk by bacteriological methods. 2. That among present available routine laboratory methods for determining the sanitary quality of milk the bacteria count occupies first place. 3. That bacteriological standards should be a factor in classifying or grading milks of different degrees of excellence. 4. That in determining the grade or class of a raw milk the specimen taken for bacteriological examination should be of milk as offered for sale. 5. That there should be bacteriological standards for pasteurized milk which should require laboratory examination of samples immediately before pasteurization as well as of milk ofPered for sale. 6. That the bacteria count of milk indicates its quality and history as it is modified by contamination, handling, dirt, temperature, or age. A high, count indicates the necessity of investigation and inspection. 240 Principles of Legislative Milk Control. 7. That there be ailopted as standards for making the bacteria count the standard methods of the American I'nhlic Health Association, laboratory section, recommending, however, the following aniendiiionts: A. That the culture nu^dium used for testing milk be identical in its composition and reaction with the culture medium used for the testing of water provided in the standard methods of water analyses of the American Public Health Association. B. That incubation of plate cultures be made at 37° C. for -iS hours. The bacterial standards given in the report are the work of a special committee of bacteriologists who considered all of the bac- terial standards now in nse. It is believed that the standards suggested are fair and wise and give full consideration to the state of the industry and of public health control. The commission l)elieves that the adoption and enforcement of these bacterial standards will be more effective thari any other one thing in im- proving- the sanitary character of pnl)lic milk supplies. The en- forcement of these standards can he carried out only by the roguhir and frequent laboratory examinations of milks for the numbers of bacteria they may contain. Chemical Standards. The chemical standards suggested are the work of a special committee, composed of chemists, which has carefully considered the natural composition of milk and the Federal and State stand- ards already established. The standard of 3.25 per cent fat and 8.5 per cent solids, not fat, here proposed is in accordance with the recommendations of the Association of Official Agricultural Chemists and has been adopted by the United States Department of Agriculture and by a larger number of States than has any other standard. The simplification of the Babcock test makes the determination of fats and solids not fat an easy procedure quickly applied. Such chemical examinations of milk can be readily adopted and executed by any health-board laboratory at a very moderate expense. It is believed that such chemical standards as are suggested will inflict no real hardship on the milk producers of this country and that the provision regarding substandard milks is a liberal one. Microscopic Examination of Milk. Because of studies which have been made during the past year the commission thinks it wise to omit temporarily any definite statement on the subject of microscopical examination of milk, and the determination of pus and bacteria by sedimentation methods, nntil further studies have been made. A special subcommittee has been appointed for this purpose which will make studies during the present year and the commission will take action on this matter at one of its later meetings. Labeling' and Grading Milk. 241 Mislabeling. The commission resolved that the sale of milk which is mis- labeled or misbranded shall be punished by suitable penalties. Publicity. The commission fully considered the matter of the publication of laboratory examinations of milk by city and town health authori- ties. When proper standards and regulations are established and adequate facilities furnished for laboratory work, it is believed that the laboratory tests will give an index of the character of the milk delivered to the public by milk sellers which is entirely fair and impartial. There can be no objection to publicity under such circumstances. It is an advantage to the seller of high-grade milk. It is an advantage to the consumer who desires to select a high-grade milk. It has much educational value both to producer and consumer. Therefore the commission recommends ''that the reports of laboratory analyses of milk made by departments of health be regularly published." Medical Inspection. It is the sense of the commission that the medical inspection of dairy employees should be emphasized in all ways possible. Milk Dealer's License. The commission resolved that a dealer shall be required to have a permit or license to sell any grade or class of milk and to use a label for such class or grade. Such permit or license shall be revoked and the use of the label forbidden when the local health authorities shall determine that the milk is not in the class or grade designated. Designation of Grade. The commission resolved that the grade of milk shall be desig- nated by letter. It is the sense of the commission that the essential part is the lettering and that all other words on the label are explanatory. In addition to the letters of the alphabet, used on caps or labels, the use of other terms may be permitted so long as such terms are not the cause of deception. Caps and labels shall state whether milk is raw or pasteurized. The letter designating the grade to which milk belongs shall be conspicuously displayed on the caps of bottles or the labels on cans. Classification of Milk. It was resolved that the classification of milk contained in the first report of the commission be amended as follows : Milk shall be divided into three grades, which shall be the 16 242 Principles of Legislative Milk Control. same for both large and small cities and towns, and wliicli shall be designated by the lirst three letters of the alphabet. The re- quirements shall be as follows : Grade A. Haw mill. — Milk of this class shall come from cows free from disease as determineil by tuberculin tests and physical examinations by a qualified veterinarian, and shall be produced and handled by employees free from disease as determined by medical inspection of a qualified physician, under sanitary conditions such that the bacteria count shall not exceed 100,000 per cul>ic centimeter at the time of delivery to the consumer. It is recommended that dairies from which this supply is obtained shall score at least 80 on the United States Bureau of Animal Industry score card. Pa.'^tciiriccd milt. — Milk of this plass shall come from cows free from disease as determined by physical examinations by a qualified veterinarian and shall be proiluced and handled under sanitary comlitions such that the bacteria count at no time exceeds 200,000 per eu])ie centimeter. All milk of this class shall be pasteurized under official supervision, and the bacteria count shall not exceed 10,000 ])ev cubic centimeter at the time of delivery to the consumer. It is recommended that dairies from which this supjily is obtained should score 65 on the United States Bureau of Animal Industry score card. The above represents only the minimum standards under which milk may be classified in grade A. The commission recog- nizes, however, that there are grades of milk which are produced under unusually good conditions, in especially sanitary dairies, many of which are operated under the supervision of medical associations. Such milks clearly stand at the head of this grade. Grade B. ]\Iilk of this class shall come from cows free from disease as determined by physical examinations, of which one each year shall be by a qualified veterinarian, and shall be produced and handled under sanitary conditions such that the bacteria count at no time exceeds 1,000,000 per cubic centimeter. All milk of this class shall be pasteurized under official supervision, and the bacteria count shall not exceed 50,000 per cubic centimeter when delivered to the consumer. It is recommended that dairies producing grade B milk should be scored and that the health departments or the controlling departments, whatever they may be, strive to bring these scores up as rapidly as possible. Grade C. Milk of this class shall come from cows free from disease as determined by physical examinations and shall include all milk that is produced under conditions such that the bacteria count is in excess of 1,000,000 per cubic centimeter. All milk of this class shall be pasteurized, or heated to a higher temperature, and shall contain less than 50,000 bacteria per cubic centimeter when delivered to the customer. It is recommended that this milk be used for cooking or manufacturing purposes only. Whenever any large city or community finds it necessary, on account of the length of haul or other peculiar conditions, to allow the sale of grade CI milk, its sale shall be surrounded by safeguards such as to insure the restriction of its use to cooking and manufacturing purposes. Classification of Cream. Cream should be classified in the same grades as milk, in accordance with the requirements for the grades of milk, excepting the bacterial standards which in 20 per cent cream shall not exceed five times the bacterial standard allowed in the grade of milk. Chemical Standards for Milk Products. 243 Cream containing other percentages of fat shall be allowed a modification of this required bacterial standard in proportion to the change in fat. Chemical Standards. Cow's milk. — Standard milk should contain not less than 8.5 per cent of milk solids not fat and not less than 3.25 per cent of milk fat. Shim milk. — Standard skim milk should contain not less than 8.75 per cent of milk solids. Cream. — Standard cream contains not less than 18 per cent of milk fat and is free from all constituents foreign to normal milk. The percentage of milk fat in cream over or under that standard should be stated on the label. Buttermilk. — Buttermilk is the product that remains when fat is removed from milk or cream, sweet or sour, in the process of churning. Standard buttermilk contains not less than 8.5 per cent of milk solids. When milk is skimmed, soured, or treated so as to resemble buttermilk, it should be known by some distinctive name. Homogenized Milk or Cream. The commission is of the opinion that in the compounding of milk no fats other than milk fats from the milk in process should be used and that no substance foreign to milk should be added to it. The commission is opposed to the use of condensed milk or other materials for the thickening of cream unless the facts are clearly set forth on the label of the retail package. Regarding the process of homogenizing, the commission resolved as follows : That homoffenized milk or cream should be so marked, stating the percentage of fat that it contains. Adjusted Milks. On the question of milks and creams in which the ratio of the fats to the solids not fat has been changed by the addition to or subtractionof cream or milk fat the commission has hesitated to take a position. On the one hand they are in favor of every procedure which will increase the market for good milk and make the most profitable use of every portion of it. On the other, they recognize the sensitiveness of milk, the ease with which it is con- taminated, and the difficulty of controlling, standardizing, skim- ming, homogenizing, souring, etc., so that contaminations do not occur and inferior materials are not used. On this subject the commission passed a resolution presented by a special committee as follows : Milk in which the ratio of the fats to the solids not fat has been changed by the addition to or subtraction of cream should be labeled "adjusted milk"; the "label should show the minimum guaranteed percentage of fat and should comply with the same sanitary or chemical requirements as for milk not so standardised or modified. 244 Princii)les of Lesiislativc ]\Iilk Coiilrol. Regulation of Market Milk on Basis of Guaranteed Percentage Composition. 1. Sellers of milk should be permitted clioice of one of two systems in handling' market milk. Milk can be sold, first, under the regular standard, or, second, under a guaranteed statement of composition. 2. Any normal milk may be sold if its per cent of fat is stated. In case the per cent of fat is not stated, the sale will be regarded as a violation unless the milk contains at least 3.25 per cent of milk fat. 3. As a further protection to consumers, it is desirable that when the guaranty system is used there be also a minimum guaranty of milk solids not fat of not less than 8.5 per cent. 4. Dealers electing to sell milk under the guaranty system should be required to state conspicuously the guaranty on all con- tainers in which such milk is handled by the dealer or delivered to the consumer. 5. The sale of milk on a guaranty system should be by special permission obtained from some proper local authority. Penalty. Every milk ordinance should contain a penalty clause. Extension Work. The commission indorsed the efforts of the New York Milk Committee to obtain funds for the formation of a bureau of exten- sion work, such bureau to act as a collecting station for informa- tion regarding standards and regulations as to milk adopted by cities and towns in the United States. The Inireau should also furnish information to such cities and towns as appeal for aid in the adoption of milk standards and should conduct a construct- ive program by placing in the field a man who would visit com- munities interested in establishing milk standards; and it may use the members of the commission on milk standards for carrying on the work of the bureau so far as possible in their own localities. The commission has confined its report rather closely to the standard requirements for milk. These requirements can not he met unless proper measures are taken. For instance : The milk must be produced from healthy cows in clean surroundings, and must then be promptly chilled and kept cool thereafter. The hand- ling at all points must be done by healthy employees — employees w^ho are not carriers of contagion. The reports of the subcommittees on the methods of produc- tion, handling, and distribution, while not properly a part of the report itself, are set forth in the following pages. Licenses and Permits for Dealers. 245 STANDARD RULES FOR THE PRODUCTION, HAN- DLING, AND DISTRIBUTION OF MILK. As a basis for the promulgation of rules and recommendations governing the production, handling, and distribution of milk, it is recognized that we have to deal with two kinds of milk, raw and pasteurized, although there may be several grades of each of these two kinds. In order for any grade to be safe, it is recommended that the regulations herein set forth under the heading "Ke- quirements'' should be enforced. The regulations herein set forth under the heading "Eecommendations" should be adopted wher- ever practicable as a means of improving the milk supply above the actual point of safety. (The term ''milk" shall be construed to include the fluid derivatives of milk wherever such construction of the term is applicable.) LICENSES. Requirements. No person shall engage in the sale, handling, or distribution of milk in until he has obtained a license therefor from the health authorities. This license shall be renewed on or before the 1st day of of each year and may be suspended or revoked at any time for cause. Recommendations. The application for the license shall include the following statements: (1) Kind of milk to be handled or sold. (2) Names of producers with their addresses and permit numbers. (3) Names of middlemen with their addresses. (4) Names and addresses of all stores, hotels, factories, and restaurants at which milk is delivered. (5) A statement of the approximate number of quarts of milk, cream, buttermilk, and skim milk sold per day. (6) Source of water supply at farms and bottling plants. (7) Permission to inspect all local and out-of-town premises on which milk is produced and handled. (8) Agreement to abide by all the provisions of State and local regulations. PERMITS. Requirements. No person shall engage in the production of milk for sale in -, nor shall any person engage in the handling of milk for shipment into -' until he has obtained a permit therefor from the health authorities. This permit shall be renewed on or before the 1st day of of each year and may be suspended or re- voked at any time for cause. 246 riiiK'i])k's of Legislative ^Milk ContiKl. PRODUCTION OF RAW MILK. Cow Stables. Requirements. 1. They shall be used for no other purpose than for the keep- ing' of cows, and shall be light, well ventihited, and clean. 2. They shall l)e ceih'd overhead if there is a loft above. 3. The Hoors shall be tight and sound. 4. The Slitters shall be water-tight. & Recommendations. 1. The window area shall be at least 2 square feet per 500 cubic feet of air space and shall be nnifornily distributed, if possible. If uniform distribution is impossible, suflicient additional window area must be provided so that all portions of the barn shall be adequately lig^hted. 2. The amount of air space shall be at least 500 cubic feet per cow, and adequate ventilation besides windows shall be provided. 3. The walls and ceilings shall be whitewashed at least once every six months, unless the construction renders it unnecessary, and shall be kept free from cobwebs and dirt. 4. All manure shall be removed at least twice daily, and disposed of so as not to be a source of danger to the milk either as furnishing a breeding place for flies or otherwise. 5. Horse manure shall not be used in the cow stable for any purpose. Milk Room. Requirements. Every milk farm shall be provided with a milk room that is clean, light, and well screened. It shall be nsed for no other pur- pose than for the cooling, bottling, and storage of milk and the operations incident thereto. Recommendations. 1. It shall have no direct connection with any stable or dwelling. 2. The floors shall be of cement or other impervious material, properly graded and drained. 3. It shall be provided with a sterilizer unless the milk is sent to a bottling plant, in which case the cans shall be sterilised at the plant. 4. Cooling and storage tanks shall be drained and cleaned at least twice each week. 5. All drains shall discharge at least 100 feet from any milk house or cow stalde. Cows. Requirements. 1. A physical examination of all cows shall be made at least once every six months by a veterinarian approved by the health authorities. 2. Every diseased cow shall be removed from the herd at once and no milk from such cows shall be offered for sale. 3. The tuberculin test shall be applied at least once a year by a veterinarian approved by the health authorities. standards for Raw Milk. 247 4. All cows wliicli react shall be removed from the herd at once, and no milk from such cows shall be sold as raw milk. 5. No new cows shall be added to a herd until they have passed a physical examination and the tuberculin test. 6. Cows, especially the udders, shall be clean at the time of milking. 7. No milk that is obtained from a cow within 15 days before or 5 days after parturition, nor any milk that has an unnatural odor or appearance, shall be sold. 8. No unwholesome food shall be used. Recommendations. 1. Every producer shall allow a veterinarian employed by the health authorities to examine his herd at any time under the penalty of having his supply excluded. 2. Certifieates showing the results of all examinations shall be filed with the health authorities within 10 days of such examinations. 3. The tuberculin tests shall be applied at least once every six months by a veteri- narian approved by the health authorities, unless on the last previous test no tubercu- losis was present in the herd or in the herds from which new cows were obtained, in which event the test may be postponed an additional six months. 4. Charts showing the results of all tuberculin tests shall be filed with the health authorities within 10 days of the date of such test. 5. The udders shall be washed and wiped before milking. Employees. Requirements. 1. All employees connected in any way with the production and handling of milk shall be personally clean and shall wear clean outer garments. 2. The health authorities shall be notified at once of any communicable disease in any person that is in any way connected with the production or handling of milk, or of the exposure of such person to any communicable disease. 3. Milking shall be done only with dry hands. Recommendations. 1. Clean suits shall be put on immediately before milking. 2. The hands shall be washed immediately before milking each cow, in order to avoid conveyance of infection to the milk. Utensils. Requirements. 1. All utensils and apparatus with which milk comes in con- tact shall be thoroughly washed and sterilized, and no milk utensils or apparatus shall be used for any other purpose than that for which it was designed. 2. The owner's name, license number, or other identification mark, the nature of which shall be made known to the health 248 Principles of Legislative ^lilk Ctnitrol. aiitiiorities, shall appear in a conspicuous place on every milk container, 3. No l)ottle or can shall he removed from a house in which there is, or in which there has recently been, a case of communi- cahle disease until permission in writing has been granted by the health authorities. 4. All metal containers and piping shall be in good condi- tion at all times. All piping shall be sanitary milk piping, in couples short enough to be taken apart and cleaned with a brush. 5. Small-top milking pails shall be used. Becom mend at ions. 1. All cans and bottles shall be cleaned as soon as jiossildc after being emptied. 2. Every convoyaiice used for transportation or delivery of milk, public carriers excepted, shall bear the owner's name, milk-license number, and business address in im- condensed gothic characters at least 2 inches in height. Handling of Milk. Requirements. 1. It shall not be strained in the cow stable, but shall be removed to the milk room as soon as it is drawn from the cow. 2. It shall be cooled to 50° F. or below within two hours after it is drawn from the cow and it shall be kept cold until it is delivered to the consumer. 3. It shall not be adulterated by the addition to or the sub- traction of any substance or compound, except for the production of the fluid derivatives allowed by law. 4. It shall not be tested by taste at any bottling plant, milk house, or other place in any way that may render it liable to contamination. 5. It shall be bottled only in a milk room or bottling plant for which a license or permit has been issued. 6. It shall be delivered in bottles, or single service containers, with the exception that 20 quarts or more may be delivered in bulk in the following cases : {a) To establishments in which milk is to be consumed or used on the premises. (b) To infant-feeding stations that are under competent medical supervision. 7. It shall not be stored in or sold from a living room or from any other place which might render it liable to contamination. Recommendations. 1. It shall be cooled to 50° F. or below immediately after milking and shall be kept at or below that temperature until it is delivered to the consumer. 2. It shall contain no visible foreign material. 3. It shall be labeled with the date of production. Standards for Raw Milk. 249 Receiving Stations and Bottling Plants. Requirements, 1. They shall be clean, well screened, and lighted, and shall be used for no other purpose than the proper handling of milk and the operations incident thereto, and shall be open to inspec- tion by the health authorities at any time. 2. They shall have smooth, impervious floors, properly graded and drained. 3. They shall be equipped with hot and cold water and steam. 4. Ample provision shall be made for steam sterilization of all utensils, and no empty milk containers shall be sent out until after such sterilization. 5. All utensils, piping, and tanks shall be kept clean and shall be sterilized daily. Recommendations. 1. Containers and utensils shall not be washed in the same room in which milk is handled. Stores. Requirements. 1. All stores in which milk is handled shall be provided with a suitable room or compartment in which the milk shall be kept. Said compartment shall be clean and shall be so arranged that the milk will not be liable to contamination of any kind. 2. Milk shall be kept at a temperature not exceeding 50° F. Recommendations. _ 1. Milk to be consumed off the premises may be sold from stores only in the original unopened package. General Regulations. Requirements. 1. The United States Bureau of Animal Industry score card shall be used, and it is recommended that dairies from which milk is to be sold in a raw state shall score at least 80 points. 2. Every place where milk is produced or handled and every conveyance used for the transportation of milk shall be clean. 3. All water supplies shall be from uncontaminated sources and from sources not liable to become contaminated. 4. ^ The license or permit shall be kept posted in a conspicuous place m every establishment for the operation of which a milk license or permit is required. 5. No milk license or permit shall at any time be used by anv person other than the one to whom it was granted. 250 Principles of Legislative ^Nlilk Control. 6. No ploco for tlio oporatioii of which a license or permit is granted shall be located within 100 feet of a privy or other possible source of contamination, nor shall it contain or open into a room which contains a water-closet. 7. No skim milk or buttermilk shall be stored in or sold from cans or other containers unless such containers are of a distinctive color and permanently and conspicuously labeled ''skim milk" or ''buttermilk," as the case may be. 8. No container shall be used for any other purpose than that for which it is labeled. Recommendations. 1. Tee useil for eoolins: purposes shall be clean and nncontaminated. 2. No person whose presence is not required shall be permitted to remain in any cow stable, milk house, or bottling- room. SUBNORMAL MILK. Requirements. 1. Natural milk that contains less than 3.25 per cent, but more than 2,5 per cent milk fat, and that complies in all other respects w^itli the requirements above set forth, may be sold, pro- vided the percentage of fat does not fall l^elow a definite percent- age that is stated in a conspicuous manner on the container; and further provided that such container is conspicuously marked "substandard milk." PRODUCTION OF CREAM. Requirements and Recommendations. 1. It shall be obtained from milk that is produced and handled in accordance with the provisions hereinbefore set forth for the production and handling of milk. LABORATORY STANDARDS FOR MILK. Requirements. 1. It shall not contain more than 100,000 bacteria per cubic centimeter. 2. It shall contain not less than 3.25 per cent milk fat. 3. It shall contain not less than 8.5 per cent solids not fat. Recommendations. 1. The bacterial limit shall be lowered if possible. LABORATORY STANDARDS FOR CREAM. Requirements. 1. There shall be a bacterial standard for cream correspond- ing to the grade of milk from which it is made and to its butter-fat content. 2. It shall contain not less than 18 per cent, milk fat. Recommendations. Same as above for milk. Principles of Legislative Milk Control. 251 SANITARY INSPECTION OF CITY MILK PLANTS Owner or manager: Trade name: . Number Cream: . Permit or License No. Remarks: . SCOKE CARD. Street and No. :- of wagons: City; Gallons sold daily- Date of Inspection : State ; -Milk : 191. Equipment. Score. Methods. Score. Perfect Alio wee Perfect Allowed - 1 Build in?: li- 2 7 12 15 2 2 1 Building 14 7 7 22 6 4 Location: Free from contan nating surroundings Cleanliness: Floors 3 Arrangement Walls 2 Separate receiving room. . . 1 2 1 1 1 1 Ceilings 2 Separate handling room. . . Separate wash room Separate salesroom Separate boiler room Separate refrigerator room. Doors and windows 1 Shafting, pulleys, pipes, etc. 1 Freedom from odors 2 Freedom from flies 3 Cleanliness: Thoroughly washed and rinsed 3 Milk-handling machin- Floors tight, sound, cleanable Walls tight, smooth, clean'ble Ceiling smooth, tight, clean- able 2 1 1 2 2 2 1 1 2 2 2 1 1 1 6 1 1 Drainage Floors 1 Sewer or septic tank... 1 Provision for light (10 per cent of floor space. Provision for pure air Screens Pipes, cans, etc 1 Sterilized with live steam. . 3 Milk-handling machin- ery 2 Pipes, cans, etc 1 Protected from contamina- Minimum of shafting, pul- Bottles leys, hangers, exposed pipes, etc Apparatus Boiler Thoroughly washed and rinsed 3 Sterilized with steam 15 min- utes 3 Inverted in clean place 1 Handling milk Received below 50° F 3 (50° to 55°, 2) ; (55° to 600,1.) Rapidity of handling 2 Freedom from undue expos- ure to air 2 ! (Water heater, 1.) Appliances for cleansing utensils and bottles Sterilizers for bottles, etc . . . Bottling machine Capping machine Wash bowl, soap, and towel in handling room Condition Milk-handling machinery 3 Pipes, couplings, and Promptness 2 Below 45° F 3 (45° to 50°, 1.) Capping bottles by machine. 2 Bottle top protected by cover 1 Storage; below 45°F 4 (45° to 50°, 3; 50° to 55°, 1.) Protection during delivery. . 2 (Iced in summer.) Bottle caps sterilized 1 Inspection 1 Cans 1 Laboratory and equipment. . . Water supply Clean and fresh Convenient and abundant . . . 1 Bacteriological work 3 Inspection of dairies supply- ing milk 3 (2 times a year, 2; once a year, 1.) Miscellaneous Cleanliness of attendants... 2 Personal cleanliness 1 Clean, washable clothing. . . 1 Cleanliness of delivery outfit 2 Total 40 1 Total 60 Score of equipment + Score for Methods = Total Score. NOTE — If the conditions in any particular are so exceptionally bad as to be inadequately ex- pressed by a score of "0" the inspector can make a deduction from the total score. [C'ir. 199] Inspector. 252 Score Card i'nv Dnirv Farms. SANITARY INSPECTION OF DAIRY FARMS SC'OKE CAIU). Iiulorsed bj' the Ollioial Dairy lustructoi'.s Association. Owner or lessee of farm: . P. O. address: . State: Total number of c-ows: . Nmnber nulkinj;: . Gallons of nnlk produced daily: . Product is sold by prochicer in fanulies,- hotels, restaurants, stores, to -dealer. For milk supply of -. Eemarks : Pernut No. (Signed) Date of inspection. Inspector. Equipment Score. 1 Methods. Score. Perfect .Vllowed PerfectlAUowed Cows. Health 6 1 1 2 4 4 1 7 1 1 5 1 1 1 2 1 1 40 Cows. 8 6 5 1 2 2 3 8 9 2 2 5 3 tjo Apparently in good health.. 1 If tested with tuberculin within a year and no tuber- culosis is found, or if tested within six months and all (Free from visible dirt, 6.) Stables. reacting animals removed. 5 (If tested within a year and reacting animals are found and removed, 3.) Food (clean and wholesome).. . Water (clean and fresh) Stables. Floor 2 Walls 1 Ceiling and ledges 1 Mangers and partitions. ... 1 Windows 1 Stable air at milking time Freedom from dust 3 Freedom from odors 2 Cleanliness of bedding 1 Well drained 1 Free from contaminating sur- roundings 1 Construction of stable Tight, sound floor and proper gutter 2 Smooth, tight walls and ceil- Clean 1 Removal of manure daily to 50 feet from stable Milk Room or Milk House. Cleanliness of milk room Utensils and Milking. Care and cleanliness of utensils Thoroughly wasned 2 Sterlized in steam for 15 minutes 3 (Places over steam jet, or scalded with boiling water, 2.) Protected from contamina- tion 3 Cleanliness of milking Clean, dry hands 3 Udders waslied and wiped. . 6 (Udders cleaned with moist cloth, 4; cleaned with dry cloth or brush at least 15 minutes before milking, 1.) Handling the Milk. Cleanliness of attendants in Proper stall, tie, and manger 1 Provision for light: Four sq. ft., (Three sq. ft., 3: 2 sq. ft., 2; 1 sq. ft., 1. Deduct for un- even distribution.) Bedding Provision for fresh air, con- trollable flue system 3 (Windows hinged at bot- tom, 1.5; sliding win- dows, 1; other openings, 0.5.) Cubic feet of space per cow 500 ft (Less than 500 ft., 2; less than 400 ft., 1; less than 300 ft., 0.) Provision for controlling temperature 1 Utensils. Construction and condition of Milk removed immediately from stable without pouring from Water for cleaning (Clean, convenient, and abun- dant.) Cooled immediately after milk- Small-top milking pail Cooled below 50° F (51° to 55°, 4: 56° to 60°, 2.) Clean milking suits Jlilk Room or Jrilk House. Location: Free from contaminat- (51° to 55°. 2: 56° to 60°, 1.) Transportation below 50° F. . . (51° to 55°, 1.5;56° to 60°, 1.) (If delivered twice a day, al- low perfect score for storage and transportation.) Total Construction of milk room Floor, walls, and ceiling. ... 1 Ligl.t, ventilation, screens, . . 1 Separate rooms for washing utensils and handling milk . . . (Hot water, 0.5.) Total Equipment + :\fetho(1s = Final Score. NOTE 1. — If any excentionally filthy condition is found, particularly dirty utensils, the total score may be further limited. . . NOTE 2. — If the water is exposed to dangerous contamination, or there is evidence of the pres- ence of a dangerous disease in animals or attendants, the score shall be 0. ICir, 199J Standards for Pasteui'ized Milk. 253 STANDARDS FOR SKIM MILK. Requirements. 1. It shall contain not less than 8.75 per cent milk solids. 2. Control of sale of skim milk: Whether skim milk is sold in wagons or in stores all containers holding skim milk should be painted some bright, distinctive color and prominently and legibly marked ''skim milk." When skim milk is placed in the buyer's container, a label or tag bearing the words "skim milk" should be attached. PRODUCTION OF PASTEURIZED MILK Pasteurized milk is milk that is heated to a temperature of not less than 140° F. for not less than 20 minutes, or not over 155° F. for not less than 5 minutes, and for each degree of tem- perature over 140° F. the length of time may be 1 minute less than 20. Said milk shall be cooled immediately to 50° F. or below and kept at or below that temperature. Cow Stables. Requirements. The same as for the production of raw milk. Recommendations. The same as for the production of raw milk. Milk Room. Requirements. The same as for the production of raw milk. Recommendations. The same as for the production of raw milk. Cows. Requirements. The same as for the production of raw milk, with the excep- tion of the sections relating to the tuberculin test. Recommiendations. That no cows be added to a herd excepting those found to be free from tuberculosis by the tuberculin test. Employees. Requirements. The same as for the production of raw milk. 254 Principles of Legislative Milk Control. Rpco)iu)i(')i(l(ifio)is. The same as for the piodiu'tion of raw milk. Utensils. Rcquironcnfs. The same as for the production of raw milk. Recommend ai ions. The same as for tlic production of raw milk. Milk for Pasteurization. Requirements. 1. The same as for the production of raw milk, witli the ex- ception of sections 1, 2, and Qh. 2. It sliall ])e cooled to 60° F. or below within two liours after it is drawn from the cow, and it shall be held at or below tliat temperature until it is pasteurized. After pasteurization, it shall be held at a temperature not exceeding 50° F. until delivered to the consumer. 3. Pasteurized milk shall be distinctly labeled as such, to- gether with the temperature at which it is pasteurized and the shortest length of exposure to that temperature and the date of pasteurization. Recom m endations. 1. Xo milk shall be repastenrized. 2. The requirements governing the production and handling of milk for pas- teurization should be raised wherever practicable. Pasteurizing Plants. Requirements. The same as under "Receiving stations and bottling plants" for raw milk. Recommendations. The same as under "Eeceiving stations and bottling plants" for raw milk. Stores. Requirements. The same as for raw milk. Recommendations. The same as for raw milk. Standards for Pasteurized Milk. 255 General Regulations. Requirements. 1. It is recommended that dairies producing milk wliich is to be pasteurized shall be scored on the United States Bureau of Animal Industry score card, and that health departments, or the controlling departments whatever they may be, strive to bring these scores up as rapidly as possible. 2. Milk from cows that have been rejected by the tuberculin test, but which show no physical signs of tuberculosis, as well as those which have not been tested, may be sold provided that it is produced and handled in accordance with all the other require- ments herein set forth for pasteurized milk. 3. Ice used for cooling purposes shall be clean. Recommendations. The same as for raw milk. PRODUCTION OF PASTEURIZED CREAM. Requirements. 1. It shall be obtained only from milk that could legally be sold as milk under the requirements hereinbefore set forth. 2. Pasteurized cream, or cream separated from pasteurized milk, shall be labeled in the manner herein provided for the label- ing of pasteurized milk. STANDARDS FOR PASTEURIZED MILK. Requirements. 1. It shall not contain more than 1,000,000 bacteria per cubic centimeter before pasteurization, nor over 50,000 when delivered to the consumer. 2. The standards for the percentage of milk fat and of total solids shall be the same as for raw milk. Recommendations. 1. The limits for the bacterial connt before pasteurization and after pasteurization should both be lowered if possible. STANDARDS FOR PASTEURIZED CREAM. Requirements. 1. No cream shall be sold that is obtained from pasteurized milk that could not be legally sold under the provisions herein set forth, nor shall any cream that is pasteurized after separation contain an excessive number of bacteria. 256 Principles of Legislative IMilk Control. ^ 2. There shall be a bacterial standard for pasteurized cream coi'respoiidiiig to the grade of milk from which it is made and to its biitterfat content. ;j. The percentage of milk fat shall be the same as for raw cream. SANITARY INSPECTION OF MILK PLANTS AND DAIRY FARMS. Bh^nk forms of the latest United States Bureau of Animal Industry score cards wliicli have been ])reviously referred to, are shown on pages 251-252. Experience has shown that there is no system of sanitary inspection so efficient as that obtained b}^ the use of these cards. Every condition pertaining to the milk is considered and rated mathematically according to its importance. The com- pleted score gives an accurate survey of the facts in a comparative manner which may serve as a permanent record, far more reliable in character than is a mere inspection unaided by the score card. This system not only provides a uniform and systematic summary, but it also has a tendency to stimulate the producer to increased eH'orts in overcoming the defects which reduce his total score. PRODUCTION OF AND STANDARDS FOR CERTIFIED MILK. The methods and standards for the production and distribu- tion of certified milk, adopted by the American Association of Medical Milk Commissions, May 1, 1912, contain all the necessary provisions for the preparation of this special milk which undoubt- edly leads all classes of milk as a food for infants. Hygiene of the Dairy. UNDER THE SUPERVISION" AND CONTROL OF THE VETERINARIAN. 1. Pastures or paddochs. — Pastures or paddocks to which the cows have access shall l)e free from marshes or stagnant pools, crossed by no stream which might become dangerously contami- nated, at sufficient distances from offensive conditions to suffer no bad effects from them, and shall be free from plants which affect the milk deleteriously. 2. Surround ill OS of hnildinqs. — The surroundings of all buildings shall be kept clean and free from accumulations of dirt, rubbish, decayed vegetable or animal matter or animal waste, and the stable yard shall be well drained. 3. Lnrafion of huildinr/s. — Buildings in which certified milk is produced and handled shall be so located as to insure proper shelter and good drainage, and at sufficient distance from other buildings, dusty roads, cultivated and dusty fields, and all other possil)le sources of contamination ; provided, in the case of un- avoidable proximity to dusty roads or fields, the exposed side shall be screened with cheesecloth. Standards for Certified Milk. 257 4. Construction of stables.— The stables shall be constructed so as to facilitate the prompt and easy removal of waste products. The floors and platforms shall be made of cement or other non- absorbent material and the gutters of cement only. The floors shall be properly graded and drained, and the manure gutters shall be from 6 to 8 inches deep and so placed in relation to the platform that all manure will drop into them. 5. The inside surface of the walls and all interior construc- tion shall be smooth, with tight joints, and shall be capable of sheddmg water. The ceiling shall be of smooth material and dust tight. All horizontal and slanting surfaces which might harbor dust shall be avoided. 6. Drinking and feed troughs. — Drinking troughs or basins shall be drained and cleaned each day, and feed troughs and mix- ing floors shall be kept in a clean and sanitary condition. ^ 7. Stanchions.— ^ta-nchions, when used, shall be constructed of iron pipes or hardwood, and throat latches shall be provided to prevent the cows from lying down between the time of cleaning and the time of milking. 8. Ventilation.— The cow stables shall be provided with ade- quate ventilation either by means of some approved artificial de- vice, or by the substitution of cheesecloth for glass in the windows, each cow to be provided with a minimum of 600 cubic feet of air space. 9. Windows. — A sufficient number of windows shall be in- stalled and so distributed as to provide satisfactory light and a maximum of sunshine, 2 feet square of window area to" each 600 cubic feet of air space to represent the minimum. The coverings of such windows shall be kept free from dust and dirt. 10. Exclusion of flies, etc.—A\\ necessary measures should be taken to prevent the entrance of flies and other insects and rats and other vermin into all the buildings. 11. Exclusion of animals from the herd. — No horses, hogs, dogs, or other animals or fowls shall be allowed to come in contact with the certified herd, either in the stables or elsewhere. 12. Bedding.— ^0 dusty or moldy hay or straw, bedding from horse stalls, or other unclean materials shall be used for bedding the cows. Only bedding which is clean, dry, and absorbent may be used, preferably shavings or straw. 13. Cleaning stable and disposal of manure. — Soiled bedding and manure shall be removed at least twice daily, and the floors shall be swept and kept free from refuse. Such cleaning shall be done at least one hour before the milking time. Manure, when removed, shall be drawn to the field or temporarilv stored in con- tainers so screened as to exclude flies. Manure shall not be even temporarily stored within 300 feet of the barn or dairy building. 14. Cleaning of cows.— Fiach cow in the herd shall be groomed daily, and no manure, mud, or filth shall be allowed to" remain 258 Piiiiciplos of Loiiislative ]\Iilk Control. upon her during milking; for cleaning, a vacnnni apparatus is reconnnended. 15. Clipping. — Long hairs shall be clipped from the udder and flanks of the cow and from the tail above the brush. The hair on the tail shall be cut so that the brush may be well above the ground. 16. Cleaning of iidders. — The udders and teats of the cow shall be cleaned before milking; they shall be washed with a cloth and water, and dry wiped with another clean sterilized cloth — a separate cloth for drying each cow. 17. Feeding. — All foodstuffs shall be kept in an apartment separate from and not directl}^ communicating with the cow barn. They shall be brought into the barn only immediately before the feeding hour, which shall follow the milking. 18. Only those foods shall be used which consist of fresh, palatable, or nutritious materials, such as will not injure the health of the cows or unfavorably affect the taste or character of the milk. Any dirty or moldy food or food in a state of de- composition or putrefaction shall not be given. 19. A well-balanced ration shall be used, and all changes of food shall be made slowly. The first few feedings of grass, alfalfa, ensilage, green corn, or other green feeds shall be given in small rations and increased gradually to full ration. 20. Exercise. — All dairy cows shall be turned out for exer- cise at least 2 hours in each 24 in suitable weather. Exercise yards shall be kept free from manure and other filth. 21. Washing of hands. — Conveniently located facilities shall be provided for the milkers to wash in before and during milking. 22. The hands of the milkers shall be thoroughly washed with soap, water, and brush and carefully dried on a clean towel immediately before milking. The hands of the milkers shall be rinsed with clean water and carefully dried before milking each cow. The practice of moistening the hands with milk is forbidden. 23. Milking clothes. — Clean overalls, jumper, and cap shall be worn during milking. They shall be washed or sterilized each day and used for no other purpose, and when not in use they shall be kept in a clean place, protected from dust and dirt. 24. Things to he avoided, hy millxers. — While engaged about the dairy or in handling the milk employees shall not use tobacco nor intoxicating liquors. They shall keep their fingers away from their nose and mouth, and no milker shall permit his hands, fingers, lips, or tongue to come in contact with milk intended for sale. 25. During milking the milkers shall be careful not to touch anything but the clean top of the milking stool, the milk pail, and the cow's teats. 26. Milkers are forbidden to spit upon the walls or floors standards for Certified Milk. 259 of stables, or upon the walls or floors of milk houses, or into the water used for cooling the milk or washing the utensils. 27. Fore milk. — The first streams from each teat shall be rejected, as this fore milk contains large numbers of bacteria. Such milk shall be collected into a separate vessel and not milked onto the floors or into the gutters. The milking shall be done rapidly and quietly, and the cows shall be treated kindly. 28. Milk and calving period. — Milk from all cows shall be ex- cluded for a period of 45 days before and 7 days after parturition. 29. Bloody and stringy milk. — If milk from any cow is bloody and stringy or of unnatural appearance, the milk from that cow shall be rejected and the cow isolated from the herd until the cause of such abnormal appearance has been determined and removed, special attention being given in the meantime to the feeding or to possible injuries. If dirt gets into the pail, the milk shall be discarded and the pail washed before it is used. 30. Make-up of herd. — No cows except those receiving the same supervision and care as the certified herd shall be kept in the same barn or brought in contact with them. 31. Employees other than milkers. — The requirements for milkers, relative to garments and cleaning of hands, shall apply to all other persons handling the milk, and children unattended by adults shall not be allowed in the dairy nor in the stable during milking. 32. Straining and strainers. — Promptly after the milk is drawn it shall be removed from the stable to a clean room and then emptied from the milk pail to the can, being strained through strainers made of a double layer of finely meshed cheesecloth or absorbent cotton thoroughly sterilized. Several strainers shall be provided for each milking in order that they may be frequently changed. 33. Dairy building. — A dairy building shall be provided which shall be located at a distance from the stable and dwelling prescribed by the local commission, and there shall be no hogpen, privy, or manure pile at a higher level or within 300 feet of it. 34. The dairy building shall be kept clean and shall not be used for the purposes other than the handling and storing of milk and milk utensils. It shall be provided with light and ventilation, and the floors shall be graded and water-tight. 35. The dairy building shall be well lighted and screened and drained through well-trapped pipes. No animals shall be allowed therein. No part of the dairy building shall be used for dwelling or lodging purposes, and the bottling room shall be used for no other purpose than to provide a place for clean milk uten- sils and for handling the milk. During bottling this room shall be entered only by persons employed therein. The bottling room shall be kept scrupulously clean and free from odors. 36. Tem^perature of milk. — Proper cooling to reduce the tem- 260 Principles of Legislative Milk Control. pcratiire to 45'' F. sliall ]>e used, and aerators shall be so situated that they can be protected from flies, dust, and odors. The milk shall be cooled immediately after being milked, and maintained at a temperature between 35° and 45° F. until delivered to the consumer. 37. Sealing of bottles. — Milk, after being- cooled and bottled, shall be immediately sealed in a manner satisfactory to the com- mission, but such seal shall include a sterile hood which com- pletely covers the lip of the bottle. 38. Cleaning and sterilizing of bottles. — The dairy building sliall be jDrovidcd with approved apparatus for the cleansing and sterilizing of all bottles and utensils used in milk production. All bottles and utensils shall be thoroughly cleaned by hot water and sal soda, or equally pure agent, rinsed until the cleaning water is thoroughly removed, then exposed to live steam or boil- ing water at least 20 minutes, and then kept inverted until used, in a place free from dust and other contaminating materials. 39. Utensils. — All utensils sliall be so constructed as to be easily cleaned. The milk pail should preferably have an elliptical opening 5 by 7 inches in diameter. The cover of this pail should be so convex as to make the entire interior of the pail visible and accessible for cleaning. The pail shall be made of heavy seamless tin, and with seams w^hich are flushed and made smooth by solder. Wooden pails, galvanized-iron pails, or pails made of rough, porous materials, are forbidden. All utensils used in milking shall be kept in good repair. 40. Water supply. — The entire water supply shall be abso- lutely free from contamination, and shall be sufficient for all dairy purposes. It shall be protected against flood or surface drainage, and shall be conveniently situated in relation to the milk house. 41. Privies, etc., in relation to ivater supply. — Privies, pig- pens, manure piles, and all other possible sources of contamina- tion shall be so situated on the farm as to render impossible the contamination of the water supply, and shall be so protected by use of screens and other measures as to prevent their becoming breeding grounds for flies. 42. Toilet rooms. — Toilet facilities for the milkers shall be provided and located outside of the stable or milk house. These toilets shall be properly screened, shall be kept clean, and shall be accessible to wash basins, water, nail brush, soap and towels, and the milkers shall be required to wash and dry their hands immediately after leaving the toilet room. Transportation. 43. In transit the milk packages shall be kept free from dust and dirt. The wagon, trays, and crates shall be kept scrupulously clean. No bottles shall be collected from houses in which com- municable diseases prevail, unless a separate wagon is used and standards for Certified Milk. 261 under conditions prescribed by the department of health and the medical milk commission. 44. All certified milk shall reach the consumer within 30 hours after milking. Veterinary Supervision of the Herd. 45. Tuberculin test. — The herd shall be free from tubercu- losis, as shown by the proper application of the tuberculin test. The test shall be applied in accordance with the rules and regula- tions of the United States Government, and all reactors shall be removed immediately from the farm. 46. No new animals shall be admitted to the herd without first having passed a satisfactory tuberculin test, made in accord- ance with the rules and regulations mentioned; the tuberculin to be obtained and applied only by the official veterinarian of the commission, 47. Immediately following the application of the tuberculin test to a herd for the purpose of eliminating tuberculous cattle, the cow stable and exercising yards shall be disinfected by the veterinary inspector in accordance with the rules and regulations of the United States Government. 48. A second tuberculin test shall follow each primary test after an interval of six months, and shall be applied in accord- ance with the rules and regulations mentioned. Thereafter, tuber- culin tests shall be reapplied annually, but it is recommended that the retests be applied semi-annually. 49. Identification of cows. — Each dairy cow in each of the certified herds shall be labeled or tagged with a number or mark which will permanently identify her. 50. Herd-hook record.— E^ach cow in the herd shall be regis- tered in a herd book, which register shall be accurately kept so that her entrance and departure from the herd and her tuberculin testing can be identified. 51. A copy of this herd-book record shall be kept in the hands of the veterinarian of the medical milk commission under which the dairy farm is operating, and the veterinarian shall be made responsible for the accuracy of this record. 52. Dates of tubercidin tests.— Tlie dates of the annual tu- berculin tests shall be definitely arranged by the medical milk commission, and all of the results of such tests shall be recorded by the veterinarian and regularly reported to the secretary of fi^e medical milk commission issuing the certificate. 53. The results of all tuberculin tests shall be kept on file by each medical milk commission, and a copy of all such tests shall be made available to the American Association of Medical Milk Commissions for statistical purposes. ^ 54. The proper designated officers of the American Associa- tion of Medical Milk Commissions should receive copies of reports 262 Principles of Legislative Milk Control. of all of tlio ainiiial, scmiaiuiual, aiul other official tuberculin tests which are made and keep copies of the same on file and compile them annually for the use of the association. 55. Disposition of coivs sick ivith diseases other than tuber- culosis. — Cows having- rheumatism, leucorrhea, inflannnation of the uterus, severe diarrhea, or disease of the udder, or cows that from any other cause may be a menace to the herd shall be re- moved from the herd and placed in a building separate from that which nuiy be used for the isolation of cows with tuberculosis, unless such building has been properly disinfected since it was last used for this purpose. The milk from such cows shall not be used nor shall the cows be restored to the herd until permission has been given by the veterinary inspector after a careful physical examination. 56. Nofificafioii of veterinary inspector. — In the event of the occurrence of any of the diseases just described between the visits of the veterinary inspector, or if at any time a number of cows become sick at one time in such a way as to suggest the out])reak of a contagious disease or poisoning, it shall be the duty of the dairyman to withdraw such sickened cattle from the herd, to destroy their milk, and to notify the veterinary inspector by telegraph or telephone immediately. 57. Emaciated coivs. — Cows that are emaciated from chronic diseases or from any cause that in the opinion of the veterinary inspector may endanger the quality of the milk, shall be removed from the herd. Bacteriological Standards. 58. Bacterial counts. — Certified milk shall contain less than 10,000 bacteria per cubic centimeter when delivered. In case a count exceeding 10,000 bacteria per cubic centimeter is found, daily counts shall be made, and if normal counts are not restored within 10 days the certificate shall be suspended. 59. Bacterial counts shall be made at least once a week. 60. Collection, of samples. — The samples to be examined shall be obtained from milk as offered for sale and shall be taken by a representative of the milk commission. The samples shall be received in the original packages, in properly iced containers, and they shall be so kept until examined, so as to limit as far as possible changes in their bacterial content. 61. For the purpose of ascertaining the temperature, a sep- arate original package shall be used, and the temperature taken at the time of collecting the sample, using for the purpose a standardized thermometer graduated in the centigrade scale. _ 62. Interval hetiveen milhinr/ and platinr/. — The examinations shall be made as soon after collection of the samples as possible, and in no case shall tlie int(U'val between milking and plating the samples be longer than 40 hours. standards for Certified Milli. 263 63. Plating. — The packages shall be opened with aseptic pre- cautions after the milk has been thoroughly mixed by vigorously reversing and shaking the container 25 times. 64. Two plates at least shall be made for each sample of milk, and there shall also be made a control of each lot of medium and apparatus used at each testing. The plates shall be grown at 37° C. for 48 hours. 65. In making the plates there shall be used agar-agar media containing 1.5 per cent agar and giving a reaction of 1.0 to phe- nolphthalein. The following is the method recommended by a committee of the American Public Health Association for the making of the media, modified, however, as to the agar content and reaction to conform to the requirements specified in section 65 : 1. Boil 15 grams of thread agar in 500 e. e. of water for half an hour and make np weight to 500 grams or digest for 10 minutes in the autoclave at 110° C. Let this cool to about 60° C. 2. Infuse 500 grams finely chopped lean beef for 24 hours with its own weight of distilled water in the refrigerator. 3. Make up any loss by evaporation. 4. Strain infusion through cotton flannel, using pressure. 5. Weigh filtered infusion. 6. Add Witte's peptone, 2 per cent. 7. Warm on water bath, stirring until peptone is dissolved and not allowing temperature to rise above 60° C. 8. To the 500 grams of meat infusion (with peptone) add 500 grams of the 2 per cent agar, keeping the temperature below 60° C. 9. Heat over boiling water (or steam) bath 30 minutes. 10. Restore weight lost by evaporation. 11. Titrate after boiling one minute to expel carbonic acid. 12. Adjust reaction to final point desired +1 by adding normal sodium hydrate. 13. Boil two minutes over free flame, constantly stirring. 14. Restore weight lost by evaporation. 15. Filter through absorbent cotton or coarse filter paper, passing the filtrate through the filter repeatedly until clear. 16. Titrate and record the final reaction. 17. Tube (10 c. e. to a tube) and sterilize in autoclave one hour at 15 pounds pressure or in the streaming steam for 20 minutes on three successive days. QQ. Samples of milk for plating shall be diluted in the pro- portion of 1 part of milk to 99 parts of sterile water; shake 25 times and plate 1 c. c. of the dilution. The committee on bacterial milk analyses of the American Public Healtli Association in Part IV of its report presented details with respect to plating apparatus and technique in part as follows : Plating apparatus. — For plating it is best to have a water bath in which to melt the media and a water-jacketed water bath for keeping it at the required temperature; a wire rack which should fit both the water baths for holding the media tubes; a ther- mometer for recording the temperature of the water in the water-jacketed bath, sterile 1 c. c. pipettes, sterile Petri dishes, and sterile dilution water in measured quantities. Dilutions. — Ordinary potable water, sterilized, may be used for dilutions. Oc- casionally spore forms are found in such water which resist ordinary autoclave steriliza- tion ; in sucli cases distilled water may be used or the autoclave pressure increased. With dilution water in 8-ounce bottles calibrated for 99 cubic centimeters * * * all the necessary dilutions may be made. Short, wide-mouthed "blakes" or wide-mouthed French square bottles are more easily handled and more economical of space than other forms of bottles or flasks. Eight-ounce bottles are the best, as the required amount of dilution water only about half fills them, leaving room for shaking. Long-fiber nonabsorbent cotton should 264 Principles of Legislative Milk Control. lie used for plugs. It is well to use care in selecting cotton for this purpose to avoid short-fiber or dusty cotton, which give a cloud of lint-like particles on shaking. Bottles * * * should be filled a little over the 99 e. c. * * * to allow for loss during sterilization. Pipettes. — Straight sides 1 c. c. pipettes are more easily handled than those with bulbs; they may be made from ordinary three-sixteenths inch glass tubing and should be about 10 inches in length. Plalin;/ /< c/; /(/(/(/ c. — The agar after melting should lo kept in the water-jacketed water bath between 40° C. and 45° C. for at least 15 minutes before using to make sure that the agar itself has reached tlie temperature of the surrounding water. If used too warm the heat may destroy some of the bacteria or retard their growth. Shake the milk sample 25 times, then with a sterile pipette transfer 1 c. c. to the first dilutior Abater and rinse the pipette by drawing dilution water to the mark and ex- pelling; this gives a dilution 1 to 100. * * * Then with a sterile pipette transfer 1 c. c. to the Petri dish, using care to raise the cover only as far as necessary to insert the end of the pipette. Take the tulie of agar from the water bath, wipe the water from outside the tube with a piece of cloth, remove the plug, pass the mouth of the tube through a flame, and pour the agar into the plate, using the same care as before to avoid exposure of the plate contents to the air. Carefully and thoroughly mix the agar and diluted milk in the Petri dish by a rotary motion, avoiding the formation of air bulibles or slopping the agar, and after allowing the agar to harden for at least 15 minutes at room temperature, place the dish bottom down in the incubator. Plating should always be done in a place free from dust or currents of air. In order that colonies may have sufficient food for proper development 10 c. e. of agar shall be used for each plate. 67. Determination of taste and odor of milk. — After the plates have been prepared and placed in the incubator, the taste and odor of the milk shall be determined after warming the milk to 100° F. 68. Counts. — The total number of colonies on each plate should be counted, and the results expressed in multiples of the dilution factor. Colonies too small to be seen with the naked eye or with slight magnification shall not be considered in the count. 69. Records of hacteriologic tests. — The results of all bac- terial tests shall be kept on file by the secretary of each commis- sion, copies of which should be made available annually for the use of the American Association of Medical Milk Commissions. Chemical Standards and Methods. The methods that must be followed in carrying out the chemi- cal investigations essential to the protection of certified milk are so complicated that in order to keep the fees of the chemist at a reasonable figure, there must be eliminated from the examination those procedures which, whilst they might be helpful and interest- ing, are in no sense necessary. For this reason the determination of the water, the total solids and the milk sugar is not required as a part of the routine examination. 70. The chemical analyses shall be made by a competent chemist designated by the medical milk commission. 71. Method of ohtaininf) samples. — The samples to be exam- ined by the chemist shall have been examined previously by the standards for Certified Milk. 265 bacteriologist designated by the medical milk commission as to temperature, odor, taste, and bacterial content. 72. Fat standards. — The fat standard for certified milk shall be 4 per cent, with a permissible range of variation of from 3.5 to 4.5 per cent. 73. The fat standard for certified cream shall be not less than 18 per cent. 74. If it is desired to sell higher fat-percentage milks or creams as certified milks or creams, the range of variation for such milks shall be 0.5 per cent on either side of the advertised percentage and the range of variations for such creams shall be 2 per cent on either side of the advertised percentage. 75. The fat content of certified milks and creams shall be determined at least once each month. 76. The methods recommended for this purpose are the Bab- cock {a), the Leffmann-Beam (6), and the Gerber (c). (a) Babcock test. — The Babcoek test is based on the fact that strong snlphnrie acid will dissolve the nonfatty solid constituents of milk, and thus enable the fat to separate on standing. It can be conducted by any of the Babcock outfits which are purchasable in the market. ''The test is made by placing in the special test bottle 18 grams (17.6 e. c.) of milk. To this is added, from a pipette, burette, or measuring bottle, 17.5 c. e. com- mercial sulphuric acid of a specific gravity of 1.82 to 1.83. The contents of the bottle are carefully and thoroughly mixed by a rotary motion. The mixture becomes brown and heat is generated. The test bottle is now placed in a properly balanced centrifuge and whirled for 5 minutes at a speed of from 800 to 1,200 revolutions per minute. Hot water is then added to fill the bottle to the lower part of the neck, after which it is again whirled for two minutes. Now, enough hot water is added to float the column of fat into the graduated portion of the neck of the bottle, and the whirling is repeated for a minute. The amount of fat is read while the neck of the bottle is still hot. The reading is from the upper limits of the meniscus. A pair of calipers is of assistance in measuring the column of fat." (Jensen's Milk Hygiene, Leonard Pearson's translation.) (&) Leffmann-Beam test. — The distinctive feature is the use of fusel oil, the effect of which is to produce a greater difference in surface tension between the fat and the liquid in which it is suspended, and thus promote its readier separation. This effect has been found to be heightened by the presence of a small amount of hydrochloric acid. The test bottles have a capacity of about 30 c. c. and are provided with a graduated neck, each division of which represents 9.1 per cent by weight of butter fat. Fifteen centimeters of the milk are measured into the bottle, 3 c. c. of a mixture of equal parts of amyl alcohol and strong hydrochloric acid added and mixed. Then 9 c. c. of concentrated sulphuric acid is added in portions of about 1 c. c. ; after each addition the liquids are mixed by giving the bottle a gyratory motion. If the fluid has not lost all of its milky color by this treatment, a little more concentrated acid must be added. The neck of the bottle is now immediately filled at about the zero point with one part sulphuric acid and two parts water, well mixed just before using. Both the liquid in the bottle and the diluted acid must be hot. The bottle is then placed at once in the centrifugal machine; after rotation from one to two minutes, the fat will collect in the neck of the bottle and the percentage may be read off. (c) Gerder's test. — This test is applied as follows: The test bottles are put into, the stand with the mouths uppermost; then, with the pipette designed for the purpose, or with an automatic measurer, 10 e. e. of sulphuric acid are filled into the test bottle, care being taken not to allow any to come in contact with the neck. The few drops remaining in the tip of the pipette should not be blown out. Then 11 c. c. of milk are measured with the proper pipette and allowed to flow slowly onto the acid, so that the two liquids mix as little as possible. Finally, the amyl alcohol is added. (It is important to use the re- agents in the proper order, which is — sulphuric acid, milk, amyl alcohol. If the sulphuric acid is followed by amyl alcohol and the milk last, then the residt is sometimes incorrect.) A rubber stopper, which must not be damaged, is then fitted into the mouth of the test bottle, and the contents are well shaken, the thumb being kept on the stopper to prevent 266 Principles of Legislative Milk Control. it coining out. As a considerable amount of heat is generated by the action of the sulphuric acid on the milk, the test bottle should be wrapjjed in a cloth. The shaking of the sample must be done thoroughly and quickly, and the test bottle inverted several times, so that the liquid in the neck becomes thoroughly mixed. By pressing in the rubber stopper the height of the liquid can be brought to about the zero j)oint on the scale. If only a few samples have to be analyzed ani^ Iron l->''^ Kefir 172 Kneadinsi' (see Methods of milk- in-) .' 25, fiS KoclTs London statement 10.") Knniys l~-4 230 250 4G .IG 02 39 21 IGG 3S 220 3,S 38 41 40 55 Labolinp,' and dating' milk 23S Lal)oi'atory examinations for bac- teria Laboratory standards for milk and oi'eam Lactase (see Enzymes) Lactation, connnencins' of Lactation, inllnences on 17, Lactation, periods of 10, Lactation, snstaininji- of Lactic acid producers 103, Lactoalbnmin Lactodensimeter Lactoglobulin Lacto-raucin Lactoscope Lactose Lactoserum Laws g'overnin.o' milk production . 235 Lead compounds in milk 13S Lecithin 194 Legislative control of milk 233 Leucocytes 15, 27, OG, 94, 223 Leucocytic test 24, 222 Licenses and permits for milk dealers 241, 245 Light 142 Local stimulants of the milk gland IS, 21, 5S Lymph vessels 3 Lymphocytes 27 M l\Lalignant edema 109 IMalta fever 70, 198 IMammaiy gland, activity of .... 145 Mammary gland, development of 1 Mammary gland, structure of... 8 Manmiary region 1 Manure, disposal of 144 Maiket milk, standards for 250 :Mastitis 5, 77, 125, 1.30 ]\Iedicinal agents 137 ]\Iedicinal inspection of employees 241 Mercury .'. . . 138 P.\GE Mesophiles 158 IMethods for i)rocunng sterile milk 154 Methvlene blue reductase 48 Metritis 68 Micrococcus melitensis 70 Microscopic examination of milk 240 Microscopy of milk 24 Milk, adjusted, requirements of. . 243 Milk analyses, publicity for 241 Milk and cream homogenized . . . 243 Milk and cream jnistenrized .... 255 Milk, certified, standard require- ments 250, 271 ]\rilk, chemical standards for.. 240, 243 Milk classification 2.30, 241 ]\Iilk constif nents. origin of... 32, 38 Milk Control, administrative .... 236 Milk control, fundamental princi- ples of 233, 271 ]\[ilk control in IMunich 200 Milk control, need of 2.34 Milk control, standard rules for. 235 Milk dealers, licenses for 245 Milk defects 226 Milk, diseases transmitted by.... 191 Milk duct 9, 25 Milk fat 37 Milk flow 22 Milk formation 17, 22 Milk for joasteurization, require- ments of 254 Milk globules 24, .38, 43 Milk, grading of 236, 241, 242 Milk, handling of 248 Milking, complete 145 Milking, methods of 58 Milk, injurious effects caused by. 128 Milk inspection 211 Milk in stores 249, 254 Milk, labeling and dating of 238 Milk, laboratory examination of. . 239 Milk, market, sale luider guarantee 244 Milk, market, standards for 250 Milk, microscopic examination of 240 ]\rilk, mislabeling of 241 Milk pails 147 Milk, pasteurization of 237 Milk plants, inspection of 251 Milk plasma 24, 33 Milk producing substances 18 Milk production, effect of feeding on 45 Milk production, legal require- ments of 235 Milk, i>us in 15 Milk, raw, standards for 246 Milk ridge 1 Milk room, requirements for .... 246 Index. 279 PAGE Milk secretion 146 Milk serum 33 Milk sickness 75 Milk, skim, chemical standards of 243 Milk, standards for bacteria in . . . 238 Milk stosis 15, 48 Milk, subnormal, requirements for 250 Milk sugar 33, 40 Milk vein 3 Milk wells 65 Mucin 38 N Necrosis bacillus 131 Nephritis, influence on milk pro- duction 69 Nerves 3, 16 Nervous irritation. 16 Niessen's globules 29 Nitrates and nitrites 232 Nuclei 28 Nuclei, free 28 Nutritive substances, theory of . . . 17 CEdema of the udder 4 ■Official inspection 206, 209, 211 Offspring, nutritive producing substances 18 Oidium lactis 168, 170 Opsonins 52 Organization of control 206, 209 Original ferments 46, 187, 194 Origin of milk constituents . . . 33, 38 Ostertag's method of tuberculosis eradication 121 Over extending the time of milking 48 Oxydase 46 Ozonization 202 P Paratyphoid fever from milk. . . . 192 Paratyphoid group (see also In- flammation) 5 Parenchyma 11 Parenchymatous mastitis 5 Passing of foreign substances into the milk 69 Pasteurization 193, 198, 237 Pasteurization, temperatures for. . 237 Pasteurized milk and cream, stand- ards for ...253, 255 Pasteuiizing plants 254 Pasture milk 134 Pathological products in milk. 68, 74 Pathology of the udder 15 Pavement epithelium 8 PAGE Peptonizing bacteria 162 Period between births 66 Period of incubation 159 Periods of lactation 16, 39, 65 Permits for milk dealers 245 Peroxide of hydrogen as a pre- servative 199 Peroxydase 47 Phases of decomposition 161 Phases of development of the ud- der 1, 10, 16 Phases of milk formation 22 Physical characteristics 16, 40 Pioscope 41 Plant rennet 38 Plants affecting milk 137 Polarization of sei'um 43 Pox 70 Precipitation, differentiation by. . 55 Precipitation, specific 55 Pregnancy 17, 66 Pregnancy impulse 17 Pregnancy, substances of 17 Pressure of the secretion 22 Principal constituents 33 Procurement of milk 58 Production 17 Production, diminishing of 13, l8, 22, 58, 67 Production, influences of heredity 63 Production of the milk gland. . . . .^.17, 58, 63 Protective substances of the body 48 Proteids 33 Psychrophile 157 Puberty 10 Publicity for milk analyses 241 Putrefactive bacteria 163 Putrid milk 176 Pyknometer 227 Pyobacillosis 82 Q Quantitative and qualitative stimu- lants 17 R Rabies 75 Raw milk, standards for 243 Receptors 19 Recoveiy from mastitis 15 Red blood cells 27, 66 Red milk 137, 179 Reductase 48 Reductase test 184, 216 Reduction number 186 Reduction of bacterial content. . . 155 Reduction properties , . . . 185 280 Index. PA(;E Reflexes on the genitals l(i, (il Refraction 4;i Regulation for milk control 2.'>5 Rennet 37 Rennet action 35 Rennet action on cooked milk. . . . 3(i Rennet, fermentation test 220 Rennet, inhibition 37 Rennet, inhibitory test 220 Resting' of the udder. i), 13. 14. 1.'). 2() Retaining- of milk secretion 21 Retrogression of the udder. . . .13. 44 Rothenfuss reagent 219 S Salts 33, 40 Salts, effects of feeding 135 Salvarsan r)2 Samples, collection of 211 Sanitary inspection of dairies. 251, 252 Scarlet fever from milk 192 Schardinger's ferment 48 Schardinger's test 217 Score card for dairy 252 Secretion, impulses of 16, 20 Secretion, in climacterium 10 Secretion, nerves of 3, IG, 22 Secretion of male animals 19 Secretion of newly borns 19 Secretion of the udder ...16, 22, 59 Secretion of virgin animals . .19, 20 Secretion, retention of 22 Secretion, stimulation of 10, 23 Sedimentation test 51, 222 Sediment in milk 92, 96 Separator slime 150 Serum 33, 38, 55 Shell 25 Skim milk, standards for. .. .243, 253 Skinlets 25 Slimy milk 179 Soapy milk 157, 176 Sore throat, epidemic 86, 235 Sour milk 171 Spaying, influence of 67 Specific gravity of milk. . .41, 43, 226 Sphincter 2 Spoiled food, effects of 136 Stable inspection 208 Stabling 141, 246 Stalls 143 Standards, bacterial, for milk . . . 238 Standards, chemical, for milk... 240, 243 Standards for certified milk. .256, 271 Standards for raw milk 246 Standards, laboratory 250 Staphylococci in milli 12!), 168 Starvation Stasis, blood Stasis, milk Sterile milk '. . . . Sterilization Sterilization by chemical sub- stances Sterilization l)y electricity Sterilization by heat Sterilization by ozonization Sterilization by iiltra violet I'ays. Stinuilation of the secretion 16, 17, 18, Slinuilins Straining milk Streak milking Streptococci (see also Mastitis; also Slimy milk) .5, 88, Streptococcic mastitis Streptococcic mastitis, spread of. Streptococcic mastitis, importance of Streptococci of animal origin. . . . Stringy milk Stripping- Structure of the tissue Structure of the udder Subnormal milk, requirements for Sucking', stimulation of Sugar Supei'oxydase Supervision of production Surface tension 133 4 48 153 lf)3 201 202 li)3 202 200 58 17 148 59 164 82 84 85 90 179 59 8 8 250 58 40 47 209 43 Tatmjolk 174 Tartar emetic 138 Taste of milk in disease 70 Tauruman 116 Teat 1, 2, 25 Teat duct 2 Teat wall 7, 8 Temperature for pasteurization . . 237 Tetanus 54, 169 Thermal death j^oint of bacteria. 197 Thermal limits of bacteria 157 Thermophiles 158 Throat infections transmitted by milk ". 235 Time rule for coagulation 36 Tipping- 58 Total fTolids 41, 63 Toxins 49, 53 Toxin, elimination of 54 Trommsdorff's test 51, 95, 222 Troughs, drain 144 Troughs, feeding 144 Index. 281 224 97 Tubercle bacilli, a typical 105 Tubercle bacilli, danaer to man from .103, 108, 112, 114 Tubercle bacilli, elimination of. . 103 Tubercle bacilli in milk 99, 100, 101, 103 Tubercle bacilli, types of 103 Tubercle bacilli, stability of 104 Tubercle bacilli, virulence of. 103, 106 Tubercle bacilli, stain for 223 Tubercle bacilli, thermal death point of 197 Tuberculosis 98, 192 Tuberculosis, animal inoculations for Tuberculosis, appearance of milk in Tuberculosis, Bang's method of controlling' 118 Tuberculosis, contamination of milk in 101 Tuberculosis control work, results of ..123 Tuberculosis, curative measures in 115 Tuberculosis, dangers from bo- vine ^; Ill, 112, 114 Tuberculosis immunization 116 Tuberculosis in children, bovine type of 109, 112, 114 Tuberculosis, methods of eradicat- ing lis Tuberculosis of cattle in the United States .^. 99 Tuberculosis of udder 97, 99 Tuberculosis, open 102 Tuberculosis, Ostertag's method of eradicating 121 Tuberculosis through ingestion . . . 107, 108 Tuberculosis, Siedamgrotzky's method of eradicating" 121 PAGE Tuberculosis, Ujhelyi's method of eradicating 122 Tuberculosis vaccination 117 Tuberculosis verrucosa cutis .... 113 Typhoid fever bacilli 197 Typhoid fever from milk 191 U Udder, activity of the .12, 16, 22, 59 Udder, anatomical structure of . . 2 Udder, changes in mastitis 6, 79, 97, 125 Udder, development of 1 Udder, filling of the 22, 59 Udder, function of the 9 Udder, inflammation of 5, 225 Udder, pathological changes of the .' ^....3, 15 Udder, secretion of the. . .16, 22, 59 Udder, structure of 8 Uniceptors 48 Utensils, requirements for 247 V Ventilation 142 Violet rays as a preservative .... 200 Virgin individuals 9, 10 Virgin udder 2, 9, 19 Viscosity 43 W Weather, effects of 140 Whey, long- 180 Whiteness, for establishing the quantity of fat . 41 Witches milk 19 Work, influence of 140 Y Yeasts 170 Yellow milk 137, 179 Yoghurt 171