RB 151 BBK 1 ssse ili i i ^m m SSS srshf m eaDs m| HI &S$ mSSm 1M1 HI |8& m HH B88 K Sign 18111 MS ffi TC ! .. - o > V <9 V * Y * ° w* . & °-» A <^ t. /^ <^ 'o , o .0 , s * * "V o V ^ \k- \~ \^ * • ■ • ° « ^^ - v ' • • ' ,0- ^, \ ?%, * • ,• J> • 0* [Price 25 Cents A COMMON HUMORAL FACTOR OF DISEASE AND ITS BEAR- ING ON THE PRACTICE OF MEDICINE Being a Deductive Investigation Into the Primary Cau- sation, Meaning, Mechanism and Rational Treatment, Preventive and Curative, of the Paroxysmal Neu- roses (Migraine, Asthma, Angina Pectoris, Epilepsy, Etc.), Bilious Attacks, Gout, Catarrhal and Other Affections,High Blood-Pressure, Circulatory, Renal and Other Degenerations. BY FRANCIS EVERARD HARE, M. D, LONGMANS, GREEN & CO. [Copyright, 1905, by F. E HareI LIBRARY of CONGRESS Two Copies Received FEB 13 1905 Couyngnt tniry CLASS A XXc. Hn / cs^rt r COPY 9. >v I* A COMMON HUMORAL FACTOR OF DISEASE INTRODUCTION. The argument contained in this work, proceeds, from the consideration of physiological metabolic processes, to the elucida- tion of processes which we are accustomed to regard as patho- logical : it is, therefore, in the main deductive, not inductive. Such an inquiry is of necessity severely hampered by the existing pov- erty of exact chemical knowledge of normal metabolism. But there is no reason for regarding it as hopeless. For, by a bolder use of the imagination, than is usually considered scientific from an in- ductive standpoint, it is possible to frame provisional hypotheses, which may be brought thereafter to the test of clinical experience. Many such hypotheses were tested in this way, and. being found inconsistent with established clinical facts, were abandoned. Although we are accustomed to speak of deduction and induc- tion as distinct and separate methods of inquiry, yet in practice the two are almost invariably used in combination, or rather alternately. The investigations, herein pursued, are no exception to this rule. Though I have for the most part tried to follow deductive lines, yet induction sometimes takes precedence ; and, indeed, my starting-point was a clinical observation which long remained unexplained. In the year 1889, 1 happened to prescribe for a travelling acquaintance. This gentleman was a resident of tropical China: he was in good general health, but for some years had been increasing considerably in weight: he was about forty years of age and weighed between fifteen and sixteen stone. The treat- ment prescribed was directed against the increasing corpulence : it consisted in a diet scale which largely excluded fats, carbo- hydrates, and saccharine alcoholic drinks, throwing the onus of nutrition in the main upon proteids. I lost sight of this patient until 1891, when I met him in the North of Scotland. He then informed me that he had ever since practically adhered to the plan of diet I had prescribed, not on account of the obesity, for he had fallen in weight to between eleven and twelve stone, but because he had quite ceased to suffer from periodic headaches. 1 then elicited for the first time that he had suffered from violent headaches since early boyhood : that the attacks had recurred at intervals of a month, three weeks, or a fortnight ; and that, having tried many physicians and numerous drugs without relief, he had ceased to seek advice on their account. His description of the attacks, from which he used to suffer, left me in no doubt that they were typically migrainous ; but. so imbued was T at that time with the teaching that migraine was a primary — usually a hereditary — disorder of the brain, that T reflected little on the case. I regarded the cessation of the headaches as a coincidence, or as resulting, in a sort of general way, from change of climate and habits. It was not until an almost identical result occurred in a second case, that I began to suspect a direct casual relation between the food supply and this particular variety of 'primary neurosis.' In the second case, the patient has suffered for many years from typical hemicrania. commencing with usual symptoms and ending in bilious. vomiting: the attacks recurred with great regu- larity every fortnight. He had abandoned hope of getting rid of his 'bilous attacks:' indeed, he regarded them as salutary ; but he wished to have his weight reduced. He was dieted accord- ingly as in the previous case. In three or four months, he had attained the desired reduction in weight : he then returned to his usual diet. The attacks of migraine ceased absolutely from the day on which he commenced dietetic treatment: they returned within a fortnight after the cessation of treatment, and they con- tinued to recur thenceforward with their old regularity. No other alteration in his habits had been made: although he took but little exercise at any time, his general health remained excellent. as it had always been. Such results appeared inexplicable, except on the hypothesis thai migraine, in these cases at least, was a food disease. It seemed as if something, derived from the ordinary food supply., remained unassimilated by the tissues and accumulated in the blood, inducing, at regular intervals, a kind of salutary explosion. And, since the alteration in diet, which conferred immunity from the attacks, consisted of an increase of the nitrogenous, with a decrease of the carbonaceous, intake, it seemed reasonable to ascribe to the latter the source of the accumulation. This idea, however, was manifestly out of harmony with accepted views as to the destination of the carbonaceous portion of the food in the organism. The carbonaceous portion of the food consists of the fats, carbohydrates, and two-thirds of the proteid : the nitrogenous portion, on the other hand, is nearly all found in the remaining third of the proteid. Now it seems to be always assumed that the former either undergoes rapid oxida- tion by the tissues, or is rapidly assimilated by them and laid down mainly in the form of fat ; and that it is something derived from the latter which alone is capable of accumulating in the blood. There remained the possibility that these commonly accepted views were incorrect ; and the possibility of such a fundamental error having crept in, was supported by several considerations. In particular, it was admitted that the known carbonaceous con- tents of normal blood (sugar, fat, glycogen, etc.) were liable to wide physiological variations : there was nothing to show that other carbonaceous compounds were not normally present ; and it was felt that the amount of work, done upon the chemistry of the plasma, was insufficient to justify a position of absolute negation with regard to the possibility of carbonaceous material accumu- lating in the blood to a pathological degree. Accordingly, it was determined to reconsider the whole posi- tion ab initio, and to adopt provisionally the hypothesis that car- bonaceous material might, in certain circumstances, accumulate in the blood to an ultra-physiological degree, such accumulation constituting a primary cause of pathological action. To the blood- state supposed to eventuate, the term 'hyperpyraemia' (Gr. pureia=iue\) was applied. The term implies a condition in which the contained fuel or carbonaceous matter, whatever its exact chemical composition, is in excess of the capacity of the organism for physiological disposal, whether by katabolism (combustion or oxidation) or by anabolism and storage (fat- formation, etc.). Conformably with this use of the term hyperpyraemia, we may speak of the physiological condition of the blood, in which the contained fuel or carbonaceous matter is capable of purely physio- logical disposal, as one of 'pyraemia' ; and, in accordance with the view that the fuel, or carbonaceous matter in the blood, may fluctuate within physiological limits, we may speak of high and low degrees, or grades, of pyraemia. Were it excusable to mention this crude, and possibly prema- ture, attempt at a medical generalisation in the same breath with the greatest scientific generalisation of the nineteenth century, the argument for hyperpyraemia might be compared, in some respects, with Darwin's argument for the theory of natural selec- tion. Darwin's scientific imagination led him early in his career to conceive his great theory. Provisional at first, the theory of natural selection soon ceased to be so, for it was found to correlate and explain an enormous number of accredited, but isolated and unexplained, biological observations.' Further, the truth of the theory was confirmed by the fact that the theory pointed out the way to a further series of observations, altogether new. The theory of hyperpyraemia, as already said, was suggested by a few therapeutic observations. It was at first purely pro- visional ; but it rapidly ceased to be so when seriously entertained ; for it was found to correlate and explain a large number of isolated clinical observations, otherwise inexplicable, or, at any rate, unexplained. Further, it was found (1) to indicate before- hand the direction in which such observations were to be sought, and (2) to discover what seem to me 1 to be an altogether new series of observations. An example or two will serve to make this clear. 1. If migraine depends upon hyperpyraemia, and is, as we shall argue, a conservative 'explosion' adapted to clear the blood from the carbonaceous accumulation, it follows that conditions, whether physiological or pathological, which are hostile to hyper- pyraemia, will be capable of relieving or dispersing migraine 1 I have determined to refrain from claiming priority with regard to any of the observations in this work. It is true many of the contained observations seem to me, and, I doubt not, will seem to others, entirely new; yet the prolonged use in medicine of the almost exclusively inductive method has resulted in the collection of such a mass of clinical observations, that a large number of these are now forgotten: this is especially true of such as have hitherto led to the establishment of no principle. The more one looks into the literature of the past, the more one becomes convinced of this, so that it seems Over bold to claim any observation as new. paroxysms. We shall argue that physical exercise and absti- nence from food tend to reduce, or disperse, hyperpyraemia ; and, on searching through Edward Liveing's classic work on 'Migraine and Sick-headache,' many examples of the salutary influence of both conditions upon recurring migraine paroxysms are to be found. Again, migraine and asthma have long been known to be capable of alternation, or mutual substitution, in the same individual. The obvious inference is that asthma also depends upon hyperpyraemia. If so, asthma, equally with migraine, should be relievable, or dispersable, by physical exercise and abstinence from food; and, on searching through Hyde Salter's classic work 'On Asthma,' numerous instances of the salutary influence of both conditions upon this affection are to be found. 2. Hyperpyraemia, we shall argue, is of necessity incom- patible with pyrexia of any severity or duration. Hence both asthma and migraine should remain in abeyance during pyrexia. On searching through medical literature, plenty of cases may be found in which asthma ceased during pyrexia. Hitherto I have failed to find the same recorded of migraine ; but any one can satisfy himself that the cessation of migraine during pyrexia is almost invariable. However, whether the latter is a new observation or not, what I am especially anxious to point out, is that, so far is I am concerned, the inverse relations of both migraine and asthma to pyrexia, .were in the first place pure deductions from the theory of hyperpyraemia, which deductions led up later to the discovery of the facts. One more illustration. If asthma depends upon hyperpyraemia, then the supervention of obesity should be capable of relieving asthma. This deduction prompted search for such a result — a search which ended in the discovery of Berkhart's three cases (§ 323). And so with the majority of observations, some apparently new, many obviously old, deduction preceded and observation suc- ceeded. It is this consideration, more than any other, which has served to convince me of the fundamental truth of the theory of hyperpyraemia. The argument for hyperpyraemia is therefore cumulative: it depends for its strength, both upon the number of well- accredited clinical and experimental facts which it explains, and upon the number of apparently new observations, all capable of independent proof, which it has facilitated. These facts and observations, taken together, are extremely numerous ; and probably not a tithe of them are included in this work. In that it will convey some idea of the scope of the work, it may be advantageous to refer here to a few of the more familiar physiological and pathological problems which the theory of hyperpyraemia seems capable of solving. 1. It will hardly be disputed that there is an old-standing and widespread, though vague, impression, both within and without the medical profession, that dyspeptic conditions are in a sense conservative, in that persons, so affected, are rela- tively less liable than others to become the victims of certain other and graver diseases : it is, at any rate, freely admitted that some constitutional diseases, such for example as gout, are commonly acquired by the aid of a sound stomach (Ewart). Under the theory of hyperpyraemia, these conceptions become definite and explicit. 2. Physical exercise is widely recognised as an almost essential factor in physiological health : its influence in pre- venting, and even dispersing, a host of minor ailments, such as dyspepsia, biliousness, bilious attacks, headaches, and nervous- nesses, is unquestioned ; and many authors have pointed out that, under its influence, formal attacks of migraine, asthma, epilepsy, gout, etc., may be greatly modified, if not altogether abolished. I do not think any satisfactory explanation of the therapeutic influence of physical exercise has been offered ; but if, as is maintained in this work, hyperpyraemia enters as a factor into all the above-mentioned departures from health, then a simple and complete explanation is to hand : exercise operates by dispersing hyperpyraemia through greatly increasing the combustion of carbon and the consequent output of carbonic acid. 3. It is generally admitted that extreme leanness, unless it has been attained deliberately as in training, is incompatible with perfect health ; and that increasing deposit of fat goes hand in hand with convalescence from disease and with improving health. It has also been observed that the develop- ment of obesity has. in some cases, replaced a long-standing recurrent neurosis or other recurrent affection, such as gout. No explanation oi am of these facts has been offered, but thee are all readily explicable on the theory of hyperpyraemia. For, in the process of fat-formation, carbonaceous material is with- drawn from the blood, thus relieving hyperpyraemia, upon which many forms of depraved health, recurrent neurosis, gout, etc., can be shown by independent evidence to depend : the process of fat-formation thus becomes an actual factor in, rather than a mere index of, the improvement in general health. The temperaments of the lean and fat are in general antagonistic. Lean persons tend to be physically active and energetic, if not fidgety and irritable : fat persons tend to be physically inactive and placid, if not lazy and indifferent. We commonly assume that the temperament determines the state of nutrition — that inactivity leads to corpulence, restlessness, to the opposite. The theory of hyperpyraemia does not exclude this sequence of cause and effect ; but it suggests that, in some cases, the sequence is reversed — that many lean persons, being deficient in the capacity to form fat, are constrained, in order to avert hyperpyraemia, to depend upon constant exercise, a necessity not experienced by persons of an obese tendency. 4. The meaning of menstruation has yet to be elucidated. Under the theory of hyperpyraemia and all that it involves, menstruation depends upon a tendency to continuous accumu- lation of carbonaceous material in the blood. This accumula- tion results from a retardation of combustion — a reduction of the specific coefficient of heat production — introduced at puberty by the evolution of ovarian activity : it is demanded by the preponderatingly anabolic functions of the mature female: it is devoted to the anabolism of the offspring; or, in the absence of conception, it is discharged at regularly recurring intervals during the menstrual process. This conception of the causation and meaning of menstrua- tion explains the occurrence of vicarious menstruation : the antagonism, complete or incomplete, between menstruation on the one hand, and on the other, pregnancy, lactation, hard physical exercise, exposure to cold climates, obesity, fever, diabetes, haemorrhage, and other conditions: the 'normal' symptoms of menstruation : the variations in the excretion of carbonic acid, urea and uric acid, which have been observed at puberty, each menstrual period, and the menopause: the well-known tendency for the attacks of many paroxysmal dis- orders, such as migraine, asthma, epilepsy and gout, together with numerous minor ailments, to group themselves around each menstrual epoch : the accentuation of all such disorders which supervenes on the suppression of the flow; and the special tendency for many of them to commence at the period of puberty, to be increased in severity at the menopause, and to disappear thereafter. 5. The salutary influence of pregnancy. It is an old obser- vation that some women enjoy perfect health only during preg- nancy. This is readily understood when we come to realise (1) that, during pregnancy, hyperpyraemia is less probable than at other times; and (2) that a very large number of common ailments, as well as many more or less formal paroxysmal affections, have hyperpyraemia for an essential factor. Cases are recorded in which long-standing recurrent migraine, asthma, epilepsy, and even mania, have remained in complete abeyance during pregnancy. 6. Nearly all sufferers believe that recurrent bilious attacks and paroxysmal affections, such as migraine, asthma, epilepsy, and gout, are in a sense salutary, in that each attack is apt to be succeeded by a period of considerably improved general health and comfort. So widely recognised was the salutary influence of an acute gouty paroxysm at the commencement of the nineteenth century, that deliberate endeavors were not infrequently made to precipitate attacks. Conformable with these facts, is the observation that, in many cases the attacks of these paroxysmal disorders tend to be severe in proportion to their in frequency, and conversely. All the observations, contained in the above paragraphs, are explicable on the theory of hyperpyraemia, but not, I think, upon any other. The affections, referred to, depend upon hyperpyraemia and are themselves adapted to disperse this blood-state: though pathological, they are conservative but not necessarily salutary. 7. The phenomena termed 'alternation of the neuroses,' 'neurosal transformations or metamorphoses,' have attracted much attention and speculation. Recurrent paroxysmal dis- orders, such as migraine, asthma, epilepsy, gastralgia, paroxysmal mania, and many other less definite nervous affections, have been observed to be susceptible of mutual replacement in the same individual at different periods of his life. Such alterna- 10 tions have been explained on the theory of accumulation and discharge of nerve energy : it has been supposed that nerve energy accumulates and that the paroxysmal affections, referred to, are manifestations of the discharge of this accumulated nerve energy. This explanation might appear sufficient, were it not for the fact that the 'alternation of neuroses' is but a portion of a much longer series of alternations : almost any of the above conspicuously nervous disorders may be replaced by very numerous processes, such as gout and pyrexia, affections in which the nervous element is inconspicuous and seemingly of secondary importance. This far longer series of alterna- tions is explicable only on the theory of hyperpyraemia. This theory retains the ideas of accumulation and discharge, but not as applied to nerve energy : instead, it applies these ideas to the fuel, or carbonaceous material, which is the source of all energy, nervous and other, but which is as yet unconverted into energy of any kind: further, it locates the accumulation in the blood and regards the recurrent paroxysmal affections in question as conservative manoeuvres, adapted to relieve the blood of its accumulated load. 8. The attacks of the paroxysmal affections, we are con- sidering, exhibit a remarkable preference for the small hours of the morning. Asthma, epilepsy, angina pectoris, gastralgia, gout, and other allied affections, are all especially prone to arise between midnight and about five in the morning. This is a fact which has been long observed, but for which, so far as I am aware, no definite tenable explanation has ever been offered. On the theory that these affections depend upon hyper- pyraemia, their special predilection for these hours is susceptible of a simple explanation. For, other things equal or approxi- mately so, carbonaceous accumulation will tend to vary inversely with the rate of combustion and the output of carbonic acid ; and it is during the small hours that the rate of com- bustion and the output of carbonic acid sink to the minimum. 9. Many paroxysmal affections, whether prominently ner- vous, such as migraine, or other, such as gout, have been treated with more or less success by plans of diet which are seemingly opposed to each other in nature and effect. Haig strongly recommends for migraine a diet in which the proteid intake is largely reduced and drawn in the main 11 from milk and cheese : he lays no stress upon the necessity of restricting the purely carbonaceous intake. Plans somewhat similar are commonly accepted as the best for gout. On the other hand, both migraine and gout may be treated by the Salisbury diet, which consists almost exclusively of lean meat and hot water: in this plan, the purely carbonaceous intake is almost abolished, the proteid intake considerably increased. Either plan has been attended with more or less success ; and this upon a superficial view is difficult to explain. But it will not, I think, be by any means impossible to show that both these apparently divergent methods join in one common tendency — namely, a tendency to the reduction of hyper- pyraemia. 10. A condition of unrelieved, or inadequately relieved, hyperpyraemia fully explains the almost interminable list of symptoms variously ascribed to lithaemia, the gouty, arthritic or herpetic diathesis, larvaceous, irregular, abarticular, sup- pressed or concealed gout, arthritism, uricacidaemia, etc. For it will be pointed out that all conditions, dietetic, hygienic, therapeutic, physiological or pathological — amongst the last notably acute articular gout — which are capable theoretically of dispersing the hypothetic state of hyperpyraemia, have been observed, in different cases, to abolish, temporarily at least, the whole train of morbid manifestations referred to. 11. Finally, the theory of hyperpyraemia seems to shed a new light upon the retention and excretion of uric acid, and upon the pathological potentialities of this compound, limiting these potentialities, for the most part, to true articular gout, the morbid affections dependent on urolithiasis and calculus, and certain forms of renal degeneration. The problems and observations in the above eleven para- graphs are but a few of the large number which seem to me explicable on the theory of hyperpyraemia. I have selected them because of their importance and because they are prob- ably amongst those which are most familiar to students of contemporary medicine. To attempt anything further would be out of place at the present stage of this work. But, besides offering a rational explanation of numerous medical problems and observations, the theory of hyperpyraemia seems to form a fundamental bond of union, hitherto missing. 12 between many of the theories of individual diseases, which have been best received by the medical profession, and which have stood the test of time — it seems to stand behind and complement, not in any way to contravene, many of the less comprehensive generalisations, already accepted or favourably regarded. Thus it will be found to be almost wholly consistent with, and perhaps to lend additional confirmation to, the fol- lowing: The theory that the energy of muscular action is supplied by the carbonaceous portions of the food ; and that function, whether katabolic or anabolic, is dominated by the nitrogenous supply : both Bernard's and Pavy's views as to the glycogenic function of the liver in so far as these views are not mutually antagonistic : Marey's law of the inverse relation between blood-pressure and pulse-rate : MollendorfT's theory of the mechanism of migraine : the vaso-motor theories of the mechanism of asthma as set forth by Sir Andrew Clark and others: Moxon's theory, and vaso-motor theories generally, of the mechanism of an epileptic fit: Xorhnagel's theory of functional angina pectoris : Raymond's theory of local syncope : the influence of hereditary or acquired pathological habit in perpetuating the recurrence of paroxysmal nervous disorders : Garrod's theory of gout, and Roberts's quadriurate theory : the humoral (usually termed toxic) conception of insanity, of many functional nervous disorders, and of many dermatoses : George Johnson's theory of the stop-cock action of the arte- rioles as applied to high blood-pressure, renal cirrhosis, etc.: Cohnheim's theory as to the meaning of the high blood-pressure in degenerative diseases of the kidney ; and many more. Finally, and to my mind most important of all, because fundamental, the theory of hyperpyraemia constitutes a tangible basis for the conception of the conservative principle of disease — of the vis medicatrix nature? — which has been held by practically all philosophic physicians from Hippocrates down- wards: it implies, indeed, a considerable extension of this conservative principle. The theory of hyperpyraemia is consistent with, and explanatory and confirmatory of, a smaller conception, subor- dinate to, but constituting an integral portion of, the larger conception of the conservative principle of disease : this 13 subordinate conception, held by Jonathan Hutchinson, Harry Campbell and others, is to the effect that physiological and pathological action differ from each other in degree, rather than in kind, and graduate by insensible gradations into each other. It will be admitted that physiological action is fully, and on all occasions, conservative in nature ; and we shall, I think, come to believe, from a study of the theory of hyper* pyraemia, that pathological action is, for the most part, but an exaggeration or modification of physiological action, equally 'purposive,' though less accurately adaptive, and therefore less economical, more damaging, and perhaps as a rule less successful. 14 CHAPTER I , §§ 1—36 Metabolism — Nitrogenous metabolism: nitrogenous equilibrium: nitrog- enous katabolism and excretion : nitrogenous anabolism and accretion : improbability of a nitrogenous accumulation in the blood — Carbona- ceous metabolism : carbonaceous katabolism and excretion : car- bonaceous anabolism and accretion : probability of a carbonaceous accumulation in the blood — The steam engine analogy — The problem of a physiological diet : deductive investigation : inductive investigation : harmonization of the results of deductive and inductive investigation — Summary. § 1. An enquiry into the possibility of an accumulation of carbonaceous material in the blood, whereby there arises the humoral condition we have termed hyperpyraemia, may be conveniently commenced with a brief survey of what is known or conjectured concerning the metabolism of the chief food- stuffs, namely, proteids, carbohydrates and fats. All three contain carbon in varying proportions: proteid alone contains nitrogen. The carbohydrates and fats, though differing widely in their mode of digestion and absorption and in their sub- sequent course through the circulation, present so much similarity in metabolism, that we may frequently speak of r them as one, under the term carbonaceous food-stuffs. Follow- ing the usual custom, the digestive changes of food-stuffs will be excluded from the scope of the expression metabolism (Schafer) i 1 metabolism will include only those changes which occur subsequent to absorption. § 2. Metabolism comprises two fundamentally distinct processes, namely, anabolism or assimilation, and katabolism or dissimilation : these, though distinct, may be concurrent in the one cell. Whether, however, the fresh food-material on reaching the cell is invariably in the first place built up into the substance of the cell, or whether, under certain conditions, the fresh food-material may be split by the agency of the cell, but outside its proper substance or bioplasm — whether, in short, anabolism of food-stuffs invariably precedes their katab- 1 Text-book of Physiology, Schafer, vol. i. p. 868. 15 olism — seems at present not fully determined. It is probable that, in the case of the proteid food-stuffs, such antecedent anabolism may occur; but 'it 1 is not probable that the non- proteid materials (fat, carbohydrate, gelatin) of the food become, after assimilation, built up into bioplasm, and, although they are undoubtedly taken into cell protoplasm, they can hardly be regarded as forming constituent parts of ' the molecules of its bioplasm. In this sense, therefore, they are outside, although in contact with, the bioplasm of the tissues' (Schafer). In summing up upon these questions. Schafer* says : — 'The phenomenon of contact changes is . . . too universal to be denied. Since this is so, the most reason- able view to be taken of the matter appears to be one which supposes that metabolism may occur both as a splitting up and oxidation of the molecules of living tissue or bioplasm and as a splitting up and oxidation both of unorganized proteid and of non-proteid materials outside, but in contact with, the molecules of bioplasm. Such a view ... is consistent with all the known facts, and is . . . readily applicable to the phenomena, both of animal and vegetable metabolism.' What is, however, certain is that, in all cases, the metabolic changes, whether anabolic, or katabolic, in the apported food-material, whether proteid or non-proteid, occur through the active agency of the cell or of its bioplasm. This fact is of essential importance from the standpoint of the theory of hvperpyraemia. NITROGENOUS METABOLISM. § 3. It is a fundamental biological fact that all structures, manifesting energy of any kind (muscles, nerves, gland cells, floating cells, seminal and ovarian cells, etc.), are nitrogenous. The same is true of the non-cellular digestive fluids, which prepare the food for absorption into the blood. This con- stancy of nitrogen implies the necessity of nitrogen wherever function has to be performed (Parkes). But the performance of function involves nitrogenous waste from destruction of tissue proteid. This is clearly seen 1 Text-book of Physiology, Schafer, vol. i. p. 898 ' lb. pp. 898, B99 16 during inanition. Schafer 1 says : — 'The amount of urea in the urine, during a fasting period of not too long duration, is probably a definite measure of the necessary destruction of tissue proteid which goes on within the body. . . . Such destruction occurs in spite of the fact that there is still plenty of non-nitrogenous material (fat) able to be drawn upon.' This essential continuous waste of nitrogen can only be replaced by proteid food — in other words, the anabolism of bioplasm is possible only from nitrogen supplied in the form of proteid. Though other food-stuffs such as gelatin contain nitrogen, yet they are unable to replace proteid in this respect. Consequently, the satisfactory performance of function depends upon the supply of proteid. Parkes 2 says : — Tf the nitrogen be cut off from the body, the various functions languish. . . . If it is wished to increase the manifestations of the energies of the various organs, more nitrogen must be supplied' ; and it must be supplied, as just stated, in the form of proteid. The above generalized statement is true within certain limits, whether the functions concerned consist mainly of anabolism or of katabolism. § 4. Nitrogenous equilibrium. — Since, as we have seen, the continued katabolism of tissue proteid is essential to the performance of function and therefore to life, it follows that continued anabolism of tissue proteid is no less essential. When the processes of proteid katabolism and proteid anabo- lism are evenly balanced, and when, consequently, the output of urea is practically equivalent to the intake of proteid, the body is said to be in nitrogenous equilibrium. The proteid intake, necessary for the maintenance of this equilibrium, varies with a number of circumstances. If, dur- ing total deprivation of food, an amount of proteid, exactly equal to the loss of tissue proteid as estimated by the urea excretion, is given, the loss of tissue proteid is restricted, but not abolished. 'The whole 3 of the nitrogen of the added pro- teid appears in the urine as urea, and in addition there is a certain amount, although not as much as during complete starvation, of tissue nitrogen still present in the urine. In order to keep up nitrogenous equilibrium, Voit found that it 1 Text-book of Physiology, vol. i. pp. 888, 889. 2 Practical Hygiene, 1891, p. 242. 3 Text-book of Physiology, vol. vi. p. 891, Schafer. 17 was necessary to give two and a half times as much proteid as the animal had metabolized during fasting. This result ... is due to the fact that the ingestion of proteid food directly excites the tissues to increased metabolic activity so that tissue proteid itself still becomes split up. . . . Xon-proteid substances do not produce this effect. On the contrary, the giving of gelatin, carbohydrates and fat has ... a sparing effect upon proteid metabolism and tends to diminish the amount of tissue proteid which is becoming broken down' (Schafer). Nitrogenous equilibrium can be produced with a far smaller amount of proteid, provided that, for the amount removed, an adequate quantity of any of these food-stuffs is added to the diet. Tf 1 to a starving animal, instead of what would appear to be just a sufficient amount of proteid, an excess be given, a point is at length reached at which the building up process exceeds the breaking down, and the tissues, and therefore the body generally, gain in weight. This increase in body weight, due to the laying on of tissue, proceeds to a certain point with any constant amount of added proteid, until a balance between the N laid on and the N lost is struck, when a condition of N-equilibrium is again obtained. A further increase of pro- teid food will now again produce an increase of tissue and of body weight, until again a condition of N-equilibrium is estab- lished. And this may apparently be carried up to the limit of the power of digestion of the animal for proteid food, so that ultimately fifteen times as much proteid may be metab- olised as in the condition of inanition. On the other hand, diminution of the amount of proteid food tends in the same way to gradually establish N-equilibrium on a lower level, and with a diminished body weight ; the animal losing flesh until such equilibrium becomes established, and then maintaining itself, provided the N ingested be constant, at a constant but lower level of N-equilibrium. In short "N-equilibrium is pos- sible with the most different amounts of proteid in the food" (Schafer). § 5. Nitrogenous katabolism and excretion. — The view is commonly accepted that proteid consists of two parts, namely (1) a nitrogenous part, which is discharged in the form 1 Text-book of Physiology, Schafer, vol. i. pp. S9i. 892. 18 of urea; and (2) a non-nitrogenous or carbonaceous (fatty or carbohydrate) part, which may be utilized as fuel by the tissues, or stored therein — which may, in short, behave like the carbonaceous food-stuffs 1 (Foster). Now there is reason to think that the primary katabolism or splitting of proteid into these two parts is quite unconnected with the process of oxida- tion. For, as Schafer points out on the authority of Voit, 'in 2 a dog fed with proteid, the urea was found by Feder to make its appearance in the urine within fourteen hours after feeding, whereas the removal of the remainder of the proteid molecule in the form of carbon dioxide and water did not occur for twenty-four hours after, so that the splitting of the proteid molecule must have occurred at one time and its complete oxidation at another.' Further, were nitrogenous katabolism an oxidative process in ordinary circumstances, we should expect that muscular exercise would materially increase nitrog- enous excretion ; and this, as we shall see, is not the case, except perhaps when the carbonaceous portion of the diet is of insufficient caloric value, 3 and in prolonged starvation when the tissue stores of purely carbonaceous material have been exhausted 4 (Schafer). Except in the case of the loss of nitrogenous material which occurs with the menstrual flow, nitrogenous katabolism precedes and determines nitrogenous excretion. This applies to urea which constitutes by far the greater part of the waste nitrogen of the body, and which, as Voit has shown, 5 is ex- creted in direct proportion to the amount of proteid ingested." Stewart 7 says : — 'Within the limits of nitrogenous equili- brium, which is the normal state of the healthy adult, the body lives up to its income of nitrogen : it lays by nothing for the future. In the actual pinch of starvation, the organism be- comes suddenly economical. When a plentiful supply of proteid is presented to the starving tissues, they pass at once from extreme frugality to luxury : some flesh may be put on for 1 Text-book of Physiology, Foster, 1895, pp. 789, 801, 811. 2 Text-book of Physiology, p. 894. 3 lb. vol. vi. pp. 913, 914. 4 lb. p. 889. 6 lb., Schafer, vol. i. p. 892. 9 The excretion of uric acid will be considered at a later stage of this work (Chapter XV). 7 Manual of Physiology, 1899, p. 457. 19 a short time, some nitrogen may be stored up; but the tissues soon pitch their wants to the new scale of supply and spend their proteid income as freely as they receive it.' Hence we may infer that nitrogenous katabolism, and therefore nitrog- enous excretion, is largely determined by supply. This may be regarded as the first great law of nitrogenous katabolism and excretion. § 6. A second law of nitrogenous katabolism and excretion is that, in ordinary circumstances, they are 'nearly 1 inde- pendent of muscular work, that is to say, the quantity of nitrogen excreted by a man on a given diet, is practically the same whether he rests or works' (Stewart). Foster says:* — 'We have no evidence of any nitrogenous waste at all as the result of a contraction' [of muscle] ; 'and indeed . . . the study of the waste products of the body as a whole, leads us to believe that the energy of the work done by the muscles of the body comes from the potential energy of the carbon compounds and not of the nitrogen compounds at all.' Pro- fessor J. Bauer says: 3 — 'It has been proved, chiefly through the researches of Voit. that the consumption or metabolism of albumen in the body is not raised in the least by the most laborious efforts; it is the non-nitrogenous materials only whose consumption is increased by activity. This fact is in no way opposed to the matter of experience, that the body requires a more liberal supply of albumen during hard labour ; it rather tends to counteract false conclusions from these results of experience and to make the connection clear. There can of course be no doubt that a labourer requires for the performance of a hard task powerfully developed and well- nourished muscles — that is, a large proportion of albuminous tissue in the body, for the maintenance of which a correspond- ing amount of albuminous food is necessary, as all experience of intense bodily activity goes to show.' § 7. We may, I think, formulate a third law to the effect that, in ordinary circumstances — that is, so long as there is available a sufficiency of purely carbonaceous material — nitrog- enous katabolism and excretion are independent of external 1 Manual of Physiology, Stewart, L899, p. 457. 2 Text-book of Physiology, 1895, p. 103. 3 Ziemssen's I land-booh of General Therapeuties, 1885, vol. i. p. i.">4 20 temperature. Parkes 1 says of the influence of high air tem- perature : — 'The urea is lessened as shown by experiments in hot seasons at home and during voyages (Dr. Forbes Watson and Dr. Becher).' But he adds : 2 — Tt is probable that this is simply from lessened food.' Similarly, it might fairly be presumed that any increase of urea excretion under cold weather results from increased food. In both cases, the food variations would refer to nitrogenous, especially proteid, food. § 8. The general conclusions, to be drawn from a consider- ation of these three laws of nitrogenous katabolism and excretion, would be (1) that except in the special circum- stances of a deficiency of purely carbonaceous material, the organism does not draw to any extent upon proteid to supply energy, whether as force or heat; and (2) that, with the same limitations, nitrogenous katabolism and excretion are mainly determined by supply. § 9. Nitrogenous anabolism and accretion. — Just as nitrogenous katabolism for the most part precedes and deter- mines nitrogenous excretion, so nitrogenous anabolism is a necessary condition of nitrogenous accretion. Under increased nitrogenous anabolism, there is a disturbance of nitrogenous equilibrium in a direction opposed to what occurs under increased nitrogenous katabolism, that is, the nitrogenous output falls below the nitrogenous intake. Increased nitrogenous anabolism and accretion occur under the following, amongst other, conditions : — 1. During the period of physiological growth of the organ- ism, whether, (1) as a parasite in utero, (2) as an ecto-parasite during lactation, or (3) subsequently, as an independent being. While it is certain a priori that, under these conditions, the output of nitrogen is below the intake, the fact has been demonstrated experimentally in the case of utero-gestation. Thus Reprev 3 has shown, from metabolic experiments on rabbits and dogs, that 'during pregnancy the organism absorbs more from the food and rejects less than during periods of sexual rest.' The katabolism 'of nitrogen decreases and less is excreted in the urine. Nitrogen is stored up in the body. In other words, the processes of assimilation are intensified, 1 Practical Hygiene, 1891, p. 402. 2 lb. 8 Digest of Metabolism Experiments, Atwater and Langworthy, p. 344. 21 while those of excretion are diminished. Less urea and phosphates are excreted during pregnancy than under normal conditions. The amount diminishes as pregnancy advances.' 2. During the development in size of an individual tissue from increased use, for example, muscle from increased exer- cise, as in the case of cardiac hypertrophy from increased per- ipheral resistance. We have already seen that it is impossible, in ordinary circumstances, by increasing muscular contraction to increase nitrogenous katabolism and excretion ; but the evidence, that it is easy, by this means, to increase nitrogenous anabolism and accretion, seems to me irrefutable. 3. In repair, during recovery from loss of tissue proteid, whether such loss has arisen from deficient proteid income, as in starvation or partial starvation ; or whether it has oc- curred through the pathologically exaggerated nitrogenous katabolism of pvrexia or possibly other morbid conditions (§ 104). 4. To some extent, as we have seen (§ 4), as a consequence of the ingestion of proteid in excess of the amount necessary for the maintenance of nitrogenous equilibrium. § 10. On taking a comprehensive survey of the above- mentioned conditions under which nitrogenous anabolism and accretion are increased as regards nitrogenous katabolism and excretion, we can hardly fail to be impressed by the idea that the metabolic variation is for the most part determined by the demand for new tissue. In the first two examples, the demand is manifestly created by a superadded or an increased physio- logical function. In the third, the demand results from an abnormal or pathological expenditure of the nitrogenous cap- ital of the body. In the fourth only, is there any question as to the dominant influence of demand: in this case it would appear at first sight as if supply were the determining factor. But, even here, we cannot I think finally exclude the influence of an increase of function. We have seen that an increase of proteid stimulates the tissues to increased katabolism; and it is open for us to assume that such increased antecedent katab- olism in the presence of a plentiful supply, is the real deter- mining factor of the succeeding increased anabolism and accretion. But, be thai as it may. we shall have to admit that in the great majority of cases, while a due supply of fresh proteid is essential, nitrogenous anabolism and accretion are not determined by the supply, but by the demand for fresh tissue, whether this has been created by an additional or increased function or by an exaggerated waste. § 11. Improbability of a nitrogenous accumulation in the blood. — We have arrived at the conclusions that nitrog- enous katabolism and excretion depend mainly on supply, nitrogenous anabolism and accretion, mainly on demand. Now it seems to me that these laws of nitrogenous metabolism — if they may be so designated — afford a strong a priori argument against the probability of an accumulation of nitrogenous material occurring in the blood. For it would seem, on the one hand, that the organism experiences no difficulty in get- ting rid of superfluous nitrogen, but that, on the other, some- thing of a struggle is involved in the retention of such nitrogen as is essential. Hence nitrogen, which fails to be anabolised and accreted, is discharged by an automatic mechanism. These remarks apply only to the metabolism of proteid and to the excretion of urea. The metabolism of nucleo-proteid and the excretion of uric acid, will be referred to at a later stage of this work. CARBONACEOUS METABOLISM. § 12. The subject of carbonaceous metabolism will be con- sidered in some detail in Chapters III to VI inclusive. Mean- while, it will be convenient to refer to some of its leading feature's in order to contrast them with nitrogenous metab- olism. Carbonaceous metabolism presents an almost complete contrast to nitrogenous metabolism. The purely carbonaceous food-stuffs cannot be said to be essential to the organism, since proteid is a complete food and will alone continue to support life indefinitely. Again, unlike proteid, the purely carbonaceous food-stuffs have no power to increase the meta- bolic activity of the tissues; on the contrary, fat and carbo- hydrates, as we have seen, have a sparing effect upon proteid katabolism and tend to diminish the amount of tissue proteid which is being broken down. Further, it goes without saying 23 that the purely carbonaceous food-stuffs have a sparing effect upon the katabolism of the fixed carbonaceous tissues. § 13. Carbonaceous katabolism and excretion. — Unlike the primary katabolism of proteid, carbonaceous katabolism consists essentially of a process of slow combustion or oxida- tion : as a result, oxygen is absorbed and carbonic acid given out. Except in the case of the loss of carbonaceous material which occurs with the menstrual flow, carbonaceous katab- olism precedes and determines carbonaceous excretion. In this, the katabolism and excretion of carbon and nitrogen agree. But, as we have seen, nitrogenous katabolism is largely determined by nitrogenous supply. This does not hold of carbonaceous katabolism. Stewart 1 points out that 'although the consumption of fat is to a certain extent in- creased with the supply of fat or fat-producing food, there is by no means the same prompt adjustment of expenditure to income in the case of carbon, as in the case of nitrogen.' In other words, carbonaceous katabolism and excretion do not depend, except within certain narrow limits, upon carbona- ceous supply. This may be regarded as a first law of carbonaceous katabolism and excretion. § 14. Again, in contrast with nitrogenous katabolism and excretion, is a second law of carbonaceous katabolism and excretion, namely, that they are largely dependent on physical exercise. Foster 2 says : — 'One hour's hard labour will increase fivefold the quantity of carbonic acid given off within the hour.' Parkes 3 gives the observations of Pettenkofer and Voit on this point in the following table : Weight of man experimented upon, 60 kilos=132 lb. avoir. Absorption of Oxygen in grammes. Elimination in grammes of Carbon Dioxide Water Urea. Rest day Work day 708.9 954.5 911.5 1,284.2 828.0 2,042.1 37.2 37.0 Excess on work day (with exception of urea) 245.6 372.7 1,214.1 -0.2 Tn other words, during the working day . . . 1 Manual of Physiology. L899, p. 461. 1 Text-book of Physiology, L895, p. S44. 8 Parkes' Practical Hygiene, 1891, p. .'570. 5,751 grains •>l or 13.15 ounces of carbon dioxide in excess were evolved. Expressing this as carbon, an excess of 1,568 grains or 3.58 ounces, were eliminated on the work day. There was an excess of oxidation of carbon equal to 41 per cent., and it must be remembered that the so-called "work day" included a period of rest : the work was done only during the working hours, and was not excessive' (Parkes). § 15. In further contrast with nitrogenous katabolism and excretion, is a third law of carbonaceous katabolism and excre- tion, namely, that they vary widely with the external tempera- ture. Foster says : * — 'Within a lower and higher limit, cold increases and heat diminishes the bodily metabolism, as shown by the increased or diminished consumption of oxygen and production of carbonic acid as the temperature falls or rises.' § 16. But there is a fourth law of carbonaceous katabolism and excretion — and herein carbonaceous and nitrogenous katabolism and excretion are found to be in agreement — namely that they depend largely upon the nitrogenous — that is the proteid — supply. Foster points out that proteid food augments the whole metabolism of the body, hurrying on the destruction, not only of proteid, but of carbon, food: in other words, proteid increases the excretion of carbonic acid, as well as the excretion of urea. This is in accordance with the view we have adopted, that all katabolic changes in apported food material occur through the active agency, and constitute functions, of the nitrogenous bioplasm (§ 2) ; and that function generally is increased with the supply of proteid. The power of proteid to increase the katabolism and excretion of the purely carbonaceous food-stuffs, is of extreme importance from the standpoint of the theory of hyperpyraemia. § 17. The general conclusions to be drawn from a consider- ation of these four laws of carbonaceous katabolism and excre- tion, would be (1) that, in ordinary circumstances, the organism is accustomed to draw upon the purely carbonaceous food-stuffs, fats and carbohydrates, to supply energy, whether as force or heat; and (2) that carbonaceous katabolism and excretion are mainly determined by the exercise of function. § 18. Carbonaceous anabolism and accretion. — Just as 1 Text-book of Physiology, 1895, p. S53. 2 Text-book of Physiology, 1895, p. 884. 25 carbonaceous katabolism for the most part precedes and deter- mines carbonaceous excretion, so carbonaceous anabolism is, with some possible exceptions to be afterwards considered (§ 126), a necessary condition of carbonaceous accretion. Carbonaceous anabolism and accretion concern mainly fat- formation. Later (§§ 125 to 135) I shall argue that fat-forma- tion depends fundamentaMy upon two factors, namely (1) a margin of carbonaceous material in the blood over and above the amount which is being utilized as fuel; and (2) a vital or active construction capacity on the part of the bioplasm of some of the nitrogenous tissues, which construction capacity depends, as do all functions, upon the supply of proteid in the food (§12?). Now the capacity to construct fat is always present in some degree in a physiological condition of the organism. Hence, in ordinary circumstances, fat-formation will be determined by the margin of carbonaceous material in the blood, that is, by the supply. In general terms, then, we may conclude that carbonaceous anabolism and accretion do not depend upon demand, but upon supply. § 19. Probability of a carbonaceous accumulation in the blood. — We have arrived at the conclusions that carbona- ceous katabolism and excretion do not depend (except slightly) upon supply, but upon the exercise of function ; and that carbona- ceous anabolism and accretion do not depend upon demand, but upon supply and upon a vital construction capacity on the part of some of the nitrogenous tissues. Now it seems to me that these laws of carbonaceous metabolism — if they may be so designated — afford a strong a priori argument in favour of the probability of an accumulation of carbonaceous material occur- ring in the blood in some circumstances. For, on the one hand, the exercise of the functions, force-production and heat- production, which mainly determine carbonaceous katabolism and excretion, is largely dependent on conditions, such as physical exercise and exposure to cold, which are more or less voluntary or accidental; and, on the other hand, the capacity for fat-construction may, as we shall see (§ 237), be conspicu- ously inadequate. Hence carbonaceous material, which is superfluous through a retardation of combustion from deficient physical exercise or from hot weather, will not of necessity 26 fully undergo anabolism and accretion ; neither will carbona- ceous material, which fails to be anabolised and accreted, be of necessity discharged, as in the case of superfluous nitroge- nous material, by an automatic mechanism. It would seem, indeed, that, in the case of nitrogen, accretion alone demands something of a struggle on the part of the organism, whereas in the case of carbon, something of a struggle is demanded by both excretion and accretion. These views are not in accordance with current medical thought. We are accustomed to argue as if fat-formation were on all occasions adequate to the requirements of the organism — as if carbonaceous material in the blood, in excess of the fuel requirements of the tissues, were, ipso facto, stored extra- vascularly as fat, and also to some extent as glycogen. This optimistic assumption has arisen, as seems to me, through our laying insufficient stress upon the constructive capacity of the tissues in fat-formation ; and its disproval is one of the main objects of this work. THE STEAM ENGINE ANALOGY. § 20. The preceding conclusions were originally largely suggested by the old analogy between the human organism and the steam engine. This, as Robert Hutchinson ' says, 'is a rather threadbare and not altogether accurate analogy, but it is perhaps the best that can be found. The building material of food' (proteid) 'corresponds to the metal of which the engine is constructed, the energy producers' (the non-nitrogenous, or purely carbonaceous, food-stuffs) 'to the fuel which is used to heat the boiler. Where the body differs from the engine is that it is able to use part of the material of its construction' (the carbonaceous part of the proteid) 'for fuel also.' We are often warned that it is easy to push the analogy of the steam engine too far : it is seldom suggested that it is possible to err in the opposite direction. And yet it may be that, hitherto, an over-timidity, arising through a too con- scientious adherence to the severely inductive method of inves- 1 Food and Dietetics, 1900, p. 2. 27 tigation, has unduly restricted us in the use of analogical methods in general and of the steam engine analogy in par- ticular. For this analogy seems to me much more complete than is commonly claimed. In both the steam, and the human, engine, there is in general a practical equilibrium of building material : in neither, is there carried any store of such material beyond what is in daily use: accretion in either occurs only when such is in actual demand. In the steam engine, the waste of building material is determined in the main by friction — at least it depends upon function and is not directly dependent on combustion or oxidation. In the human engine also, it depends upon function and, with an apparent exception, is not directly dependent on combustion or oxidation. This apparent exception occurs when, in consequence of a deficiency of its accustomed fuel, the organism exercises its capacity for burning its building material. On the other hand, fuel in both cases is apt to be stored in advance : its expenditure in both is strictly proportionate to the energy developed, whether as force or heat; and accretion may occur in the absence of any immediate . demand — it is apt to occur, indeed, in inverse proportion to the immediate demand. There is a further resemblance which, to my mind, is of extreme importance in practical medicine. It will be admitted that a well-constructed, large and therefore heavy, engine has a capacity for combustion, and therefore for the development of energy, which is not possessed by a smaller one — that the possible energy is largely proportionate to the amount of building material. The same is true of the human organism : the capacity for combustion, and therefore for the development of energy, is largely proportionate to the amount of anabolised proteid or bioplasm ; and it is possible, as we have seen, to increase this anabolised proteid by increasing, under proper conditions, the supply of proteid in the food. Such conditions commonly include the creation of the demand for fresh tissue through the exercise of function, as. for example, systematic muscular contractions (§ 9). But, as we have seen (§ Hi), the mere increase of proteid intake, though it may not result in an increase of anabolised proteid. increases the rate <>\ combustion. 88 THE PROBLEM OF A PHYSIOLOGICAL DIET. § 21. Our knowledge of physiological metabolism, meagre as it is, is sufficient to suggest that considerable variations in the quantity and constitution of the diet should be made in accordance with the variations in external conditions and work, inseparable from modern civilized life. In an attempt to solve the problem of a physiological diet, we may proceed in either of two fundamentally different ways. We may proceed by deduction from what we know of physiological metabolism ; and we may proceed by induction from observations of the food customs of mankind in various environments. § 22. Deductive investigation. — Since exposure to cold largely increases the expenditure of carbon in response to the increased demand for heat-production, we should infer that, under conditions, such as the approach of winter or a change of residence from a low to a high latitude, we ought to increase considerably the carbonaceous or fuel intake. And, since physical exercise largely increases the expenditure of carbon in response to the increased demand for force-pro- duction, we should infer that, under conditions such as a change from a sedentary to a laborious occupation, a similar addition to the food should be made. A fortiori, under conditions involving an increased demand for both heat and force production such as a change from a sedentary occupation in a low latitude to a laborious occupation in a high latitude, it is clear that the addition to the carbonaceous or fuel intake would be urgent. § 23. The converse of the above would necessarily follow. Under conditions, involving diminished exposure to cold or diminished physical exercise, we should infer the propriety of a considerable diminution of the carbonaceous or fuel intake ; and, a fortiori, under conditions involving a diminution of both sources of expenditure. Conformably, Robert Hutchinson says: 1 — 'Compared with the diet of muscular labour . . . the diet for mental work should be small. The reduction should probably affect the carbohydrates and fats more than proteid, for it is the two former . . . which tend to be specially made use of as muscle foods. . . . Hence it is, that it is far easier 1 Food and the Principles of Dietetics, 1900, p. 43. 29 for a man who is performing bodily labour to be a vegetarian, than for one who is engaged in mental work.' § 24. The variations in the nitrogenous or proteid intake, which should on physiological grounds be made in accordance with variations of external conditions or personal habits, are less clear. In the steam engine, the capacity for combustion will depend, inter alia, upon the size and strength of the furnace; and, if these qualities are to be assured, the supply of building material must not be stinted. So it is, perhaps, with the human engine. The capacity for combustion will depend. inter alia, upon the bulk and nutrition of the nitrogenous tissues, especially the muscles ; and to assure these qualities, a due supply of proteid is essential. Hence it may be argued that, in an environment or with personal habits which entail rapid combustion, an ample supply of proteid is demanded. But manifestly such supply will not be propor- tionate to the combustion as in the case of fuel supply. § 25. But there is another side to the question. External heat involves a diminished demand for heat-production and, consequently, a diminished combustion. But the development of energy, whether as heat or force, is not the only object of combustion. Combustion is also adapted, as we shall see later (§ 107 to 109), to clear the blood of superfluous carbonaceous material. Hence it may be argued that the diminished com- bustion, which results from the diminished demand for heat- production due to external heat, may lead, in some cases, to a deleterious accumulation of carbonaceous material in the blood ; and that this tendency is best met by an increased supply of proteid which, as we have seen, has the power of stimulating the nitrogenous tissues to increased combustion (§ 1(5). § 2(>. So also in the case of the diminished combustion which results from the diminished demand for force-production due to sedentary habits. It may be argued that, here also. there is demanded the stimulating influence of an increased proteid supply upon the oxidising nitrogenous tissues in order to compensate for the absence of physical exercise. In con- formity with this, is, I think, an observation of Clifford Allbutt. This author says: — 'I am always assured by brain workers, and I share the prejudice, that for them also a somewhat liberal diet is required.' ' 1 System of Medicine, vol. v. p. 845, 30 It must be admitted that the theoretical indications for varying the proteid supply are complex, if not conflicting. On the whole, it would seem that, while a certain minimum is essential, the variations, demanded in accordance with varia- tions of environment and personal habits, are much less than in the case of the purely carbonaceous food-stuffs. The objections to the deductive method of investigating the problem of a physiological diet, consist in the seeming lack of complete harmony which exists between the conclusions so arrived at, on the one hand, and observation of the food customs of mankind and the experience of the medical profession on the other. This subject will be returned to presently. § 27. Inductive investigation. — Sir William Roberts 2 says : — 'The science of dietetics must, I apprehend, be mainly based and built up on an observation and a study of the practices and customs of mankind in regard to their food, rather than upon a priori data supplied by physiology. In, the case of the lower animals, we assume that each creature selects from the nutrient materials within its reach those articles which are most suited to its well-being and are best fitted to promote its success in the struggle for existence, and that it is guided in this selection by an almost unerring instinct. This, like other instincts, is now explained by biologists as con- sisting essentially in an inherited experience, which has been gradually accumulated through a long line of ancestors, and is transmitted by heredity to the descendants. Accordingly, when we see an animal feeding on a particular kind of food, we conclude without hesitation that that food is, of all the nutrient materials accessible to it, the best adapted for the special wants of its economy. But we know that man, in regard to his bodily functions, is subject to the same laws as those which govern the life of the lower animals. And we cannot doubt that in the formation of his dietetic habits, man is guided by the same kind of instincts as those which guide the rest of the animal creation in the choice of their food. 'The generalised food-customs of mankind are therefore not to be viewed as random practices adopted to please the palate or to gratify an idle or vicious appetite. These customs must 2 Digestion and Diet, 1891, pp. 96, 97. 31 be regarded as the outcome of profound instincts, which corre- spond to important wants of the human economy. They are the fruit of a colossal experience, accumulated by countless millions of men through successive generations. They have the same weight and significance as other kindred facts of natural history, and are fitted to yield to observation and study, lessons of the highest scientific and practical value.' § 28. I have given this long quotation partly because of the eminence of the writer and of the weight which his teachings undoubtedly carry, but chiefly because the wide- spread adoption of such exclusively inductive views are, in my opinion, very largely responsible for the confusion which admittedly prevails at the present day in the science of dietetics. The optimistic assumption that the food-customs of the civilized races of mankind are almost of necessity physiological, seems to me unfortunate, as well as untenable. It is unfortunate because it practically precludes food as a • primary factor of disease, and thus closes the door at the out- set upon investigation in this direction. By excluding supply, it throws into undue prominence disorder of function, whether hereditary, congenital, or acquired in many incidental ways, as the original starting-point of pathological action : this source of fallacy seems to permeate modern pathology, but is, I think, especially conspicuous in disorders of the digestive system. The optimistic assumption, just referred to, is unten- able because it depends upon the further assumption that civilized man and the lower animals are subject in equal decrees to the law of natural selection — an assumption the truth of which cannot, in my opinion, be maintained. § 29. Harry Campbell * points out that 'the essential purpose of instinct and reason is to regulate the environment of the individual, to surround him by such conditions as are best suited to his existence' ; that 'man and brutes stand out in bold contrast in that reason is the chief means of the one, instinct of the other'; and further that instinct though 'the most perfect possible guide.' is fully operative only in the pres- ence of a stable environment. Now it is admitted that, in the course of ages, owing to the stability of their environment, animals have developed an 1 Causation of Disease, Chap. TI. on almost unerring instinct with regard to the selection of their food. The same is true doubtless of primitive man, and probably also to a less extent of contemporary human races whose environment has undergone little alteration through long periods. It is probable for example that the primitive Asiatic 1 'took to rice eating not from desire but from the scarcity of animal food' (Hueppe) : and that, through the operation of the law of natural selection, the modern Asiatic now lives upon an approximately physiological diet. It cannot, I think, be upheld that instinct, operating through natural selection, has exercised a preponderating influence on the formation of the present food customs of Western civilized man. Instinct, as already stated, is fully operative only under a stable environment; and civilization implies an ever-changing environment. Further, the growth of reason, in itself an essential cause of the unstable environ- ment, tends to blur the precision of instinct. Hence civilized man has come to depend largely, if not mainly, on the former. But reason, though doubtless far better adapted to a changing environment, is, as argued by Harry Campbell," 'a far less perfect guide than instinct' under a stable environment. For 'in order that reason shall on all occasions give a correct result, two things are necessary, man must be acquainted with every natural law, and he must be gifted with perfect reasoning power.' Now, whatever may happen in the future, it is certain that such conditions are unattainable now. Conse- quently, we might perhaps regard the present in the light of an 'evolutionary interregnum' — an interregnum succeeding the despotic reign of instinct and preceding that of reason in its full development. Hence, it must, I think, be admitted that, into our present civilized food customs, there have entered many factors in addition to the operation of natural selection. Amongst these, we shall have to include greatly increased accessibility to a variety of food-stuffs through advancing knowledge in the science and art of manufacture and through increased facilities of transport, cultivated tastes, sentimentalism, fashion and many more. If this is true, then we may have in our present 1 Prof. Ferdinand Hueppe in Brit. Med. Journ., 1901, March 2. 2 Causation of Disease, pp. 192 et seq. 33 food customs a primary factor of disease possessing vast potentialities. Conformably, we shall find that practically all the affections, which we are ascribing in this work to hyperpyraemia, are more or less peculiar to civilized, especially to highly civilized, man: and they are comparatively absent from man in a savage state; and that they are unknown in the lower animals, except perhaps in such domesticated varieties as have come largely under the civilized human environment. Hence we shall have to regard hyperpyraemia as largely a result of civilization or of the evolutionary interregnum implied in the development of civilization. Moebius has said: — 'The tendency to headache is a part of the degeneration which is inseparable from civilization.' Xow headaches — at any rate, recurrent sick-headaches — are amongst the commonest of all the mani- festations of hyperpyraemia; and if we might use the term 'degeneration' to cover conditions which depend upon inade- quately rapid adaptation to the ever-changing environment of civilization, then the view held by Moebius would include the view preferred in this work. § 30. Harmonization of the results of deductive AND inductive investigation.— The conclusions we have reached by deduction from physiology are supported to some extent by observation of the food customs of mankind. Thus in the Arctic Zone the Esquimaux live largely upon fat, the most concentrated form of purely carbonaceous, or fuel, food. Xor are there wanting examples of races inhabiting hot climates —the aborigines of Northern Australia, the Indians of parts of South America — who live largely upon flesh, the main source of proteid. And Schafer 1 states that 'it has been observed by Tiegel that the Japanese rickshaw runners con- sume rice in large quantities and at frequent intervals during their periods of work, whereas on off days, they live mainly on a flesh diet. 5 § 31. Consistent with these observations is the experi< of a minority of the profession (of which I am one) that proteid is practically as essential in a hot climate and under sedentary conditions of life as under the opposite circum- stances; but that, under both external heat and diminished 1 'Text-hook of Physiology, vol. i. p. 915. 3 1 physical exercise, the purely carbonaceous food-stuffs should be largely reduced ; and conversely. § 32. On the other hand, our physiologically deduced con- clusions are seemingly in conflict with other observations. Many Asiatic races, such as the natives of India, Java, parts of China, and the South Sea Islands, take comparatively little proteid and live very largely on carbohydrates, such as rice, sago and fruit. § 33. Consistent with, perhaps largely based upon, the latter series of observations, is, I think, the opinion of the majority of the medical profession upon dietetics. It is held that, under increased heat, meat should be largely eschewed, the carbohydrates somewhat increased ; and that meat, except in small amount, is an improper food for those whose occupa- tion is sedentary. The last is a deep-rooted and old-standing conviction, dating from long before the time when Liebig formulated his theory (now exploded) 1 that the functional activity of the nitrogenous tissues involved a proportionate waste of the structural elements of those 'tissues, and necessitated a corresponding consumption of nitrogenous material to replace that loss' (Yeo). Indeed the influence of this conviction may be traced in the Old Testament. Further, it seems to be the general view that one class of the purely carbonaceous or purely fuel foods, namely, the carbohydrates, is, except in the presence of certain clearly denned diseases (glycosuria, diabetes), a suitable and practically harmless nutriment in all circum- stances. § 31 Now it will be argued throughout this work that the views of tfie aforementioned minority of the medical pro- fession are correct and that the conclusions deducible from physiologv are applicable in the majority of cases to practice, both hygienic and therapeutic. Hereupon, the following crucial questions arise. If the views of the majority are incorrect (1), how is it that the purely carbonaceous or fuel intake, which must often be excessive from the standpoint of physiological metabolism, is not a frequent primary cause of disease? and (2) how is it — and the fact of this objection may be admitted beforehand — that the purely carbonaceous or fuel intake can be increased — as in the substitution of a vegetarian 1 Food in Health and Disease, I. B. Yeo, 1897, p. 12. 35 or modified vegetarian, for an ordinary mixed, diet — under conditions, which theoretically demand a reduction, with, in some cases, absolute benefit? § 35. The answer to these questions largely constitutes the purpose of this work. Meanwhile, it may be stated in anticipation (1), that a relatively excessive intake of carbona- ceous material is one of the most fertile of the causes of disease, the diseases so arising being, for the most part, those whose fundamental pathology or meaning has hitherto baffled investigation; and (2) that an increase of the purely carbonaceous or fuel intake does not of necessity involve any increased intrusion of such material into the blood ; often the contrary, indeed, since, as we shall argue, the digestion and absorption of carbonaceous material depends largely upon the nitrogenous or proteid intake (§§ 55 to 60). In short, it will be argued that the views of the aforesaid majority are necessarily incorrect only from the standpoint of metabolism, using this term in its restricted sense ; and that these views frequently become correct when the processes of digestion and absorption are included within the scope of the term. § 36. In this chapter, I have endeavored to contrast with each other some of the fundamental laws of nitrogenous and carbonaceous metabolism ; and to show thereby, and from the analogy of the steam engine, that any excess of nitrogenous material in the blood tends to be automatically excreted, but that a carbonaceous excess tends, in some circumstances, to accumulate in the blood. 36 CHAPTER II §§ 37—61 Carbon income : carbonization of the blood, or the digestion and absorption of carbonaceous material — Oral digestion : conservative influence of oral disease : secondary effects of oral disease — Gastric digestion : conservative influence of gastric dyspepsia : secondary effects of gas- tric dyspepsia — Intestinal digestion and dyspepsia. — Evidence that carbonization of the blood is a vital action and depends on the supply of proteid — Summary. §37. It will be convenient to consider next the processes by which the blood is supplied with fuel or carbonaceous material. These comprise the numerous processes whereby the raw carbonaceous material, contained in the proteid, fats and car- bohydrates of the food, is first suitably modified and then transported from the surface of the alimentary mucous mem- brane into the blood — in short, digestion and absorption, processes which we shall often find it convenient to speak of conjointly as 'carbonization.' Digestion occurs in the organs of primary digestion, the mouth, stomach and intestinal canal: absorption occurs to some extent in all three, but mainly in the last. Both processes, though they include various kinds of mechanical and chemical action, are manifestations of vital energy — they are vital functions; and 'since every structure of the body, in which any form of energy is manifested ... is nitrogenous,' the due performance of these functions will de- mand, inter alia, a due supply of proteid in the food. Hence the primary essentials for the due performance of the complex function of carbonization, as carried on in ordinary circum- stances. 1 will concern supply and function : (1) a due supply of carbonaceous material; and (2) a due functional capacity on the part of the organs and tissues concerned, this depending largely upon the supply of proteid. § 38. The digestive functions of the mouth are mainly mechanical : the only food-stuffs which are chemically altered 1 We are not considering here the carbonization of the blood which occurs during starvation : that is an essentially different process and will be referred to later (§§ 187 to 189). 37 are the starches : these are converted into soluble sugar. Although 'the action of the human saliva. is very energetic, indeed, almost instantaneous' 1 (Bauer), yet the starches will have to be intimately mixed, and remain a certain minimum time in contact, with the saliva. For efficiency of oral diges- tion, therefore, as for efficiency of the whole complex process of carbonization, the primary essentials will concern supply and function. 1. The amount and character of the food presented. The food should be in such a form that thorough mastication and insalivation is necessary before swallowing is possible : biscuits, rusks, breadcrust, etc., would be ideal forms. 2. The functional capacity of the organs and fluids of oral digestion. The teeth, mucous membranes and glands will have to be in good order: this will imply due nutrition by a due supply of proteid. The saliva will have to be chemically active : for this, it will have to be alkaline in reaction ; and, since it is a nitrogenous fluid, probably it will be dependent upon the proteid supply for its constant reinforcement. It is probable, therefore, that the amount of proteid in the daily diet exercises no inconsiderable influence upon the diges- tion of carbohydrate material in the mouth, and less directly, upon its subsequent absorption. § 39. Conservative influence of oral disease. — In the commoner forms of mouth disease, such as dental caries, gingivitis and pyorrhoea alveolaris, mastication is necessarily imperfect and the saliva is not infrequently acid. Hence there will be a failure of salivary digestion, and by so much proba- bly, a failure of subsequent absorption. And, if, as we are arguing in this work, a long series of morbid affections of the general system depend primarily upon hyperpyraemia, then we shall be entitled to regard many of the functional and structural disorders of the oral cavity as at least incidentally conservative in their influence. Conformably, Sir Henry Thompson thinks that most people eat their way to the grave with their teeth ; and many of the older physicians laid great stress upon the condition of the teeth as signs of the 'arthritic diathesis,' a constitutional state which, we shall argue later 1 Prof. J. Bauer in Ziemssen's Hand-book of General Therapeutics, vol. i. p. 100. 38 (§§ 858 to 865), is synonymous with hyperpyraemia. Lay- cock, 1 speaking of the characteristic features of this diathesis, refers to 'teeth massive, well-enamelled, regular, even undecayed in advanced life' (J. M. Fothergill). The great increase of dental caries and other inflammatory conditions of the mouth during recent years, is beyond dis- pute : as to the cause of such increase there has been much speculation but little agreement. Here, as in other depart- ments of pathology, the dominant prejudice against animal food has been conspicuous: excessive consumption of meat, together with an assumed hereditary tendency to degenera- tion, has been claimed as the essential factor. But recently, there has been a revolt against this teaching: Dr. J. Sim Wallace argues that the modern finely pulverized carbo- hydrate food-stuffs are the directly responsible agents ; and in this he is supported by a report of a 'Decay of Teeth Com- mittee.' The report, 2 referred to, says: — 'Comparing the con- dition of the mouth after a meal of flesh and after some form of carbohydrates, in the one case the mouth is comparatively clean, a few fibres perhaps remaining between the teeth, which may be easily removed : in the other case, the interstices between the teeth and the fissures of the teeth are packed with soft masses of fermentable material, difficult, and in fact impossible, to remove entirely, and thus presenting all the conditions most 'favourable for the production of lactic acid.' The following seems a reasonable view of the etiology of dental caries. Carbohydrate retention leading to fermenta- tion and acidity of the secretions and contents of the mouth : erosion of the protecting enamel ; and decay of dentine through bacteria thus admitted to the body of the teeth. And it is more than probable, as ably argued by Harry Campbell, 3 that pyorrhoea alveolaris has a similar origin in soft carbohydrate food. Here it will probably be objected that the Hindoos, who are in the main starch eaters, possess as a rule, large, healthy, strong, and exceptionally well-developed teeth. It is apt to be overlooked, however, that, with this race, careful and regular cleansing of the teeth is imposed as a part of their religious 1 Gout in its Protean Aspects, J. M. Fothergill, 1883, p. 36. 2 Quoted in the British Medical Journal, August 11, 1900. 3 'Observations on Mastication,' Lancet, July 25, 1903, pp. 219, 220. 39 ritual ; and it is easy to see that decay may be prevented by a careful and systematic toilet of the mouth in spite of injurious food-customs. Hindoo vegetarianism, such as it is (for it is by no means exclusive), is in all probability a result of envi- ronment; and it is conceivable that the rigid enjoynment of mouth cleanliness has, in their case, its origin in the remote past in an experience of its dominant necessity under the food conditions of the country. § 40. A better index of the influence of food may be obtained from an examination of the teeth of races who take no special care in their preservation. Dr. \Y. A. Alden 1 of Montana, U.S.A., says: — 'I have examined in the last 21 years hundreds of these (Crow) Indians, and have yet to find one with pyorrhoea alveolaris. I have found it in negroes and in the mound builders, but not so in the Crow Indian tribe, as the Crows were almost exclusively flesh eaters, their diet being buffalo, elk, mountain sheep, deer and antelope. I present a model which I have obtained from Iron Bull, Crow Chief, at the age of 70 years.' The illustration of the model, referred to, shows that every tooth in both jaws is present : that they are all perfect in .size and shape; and that no trace of decay is anywhere visible. The aborigines of Australia, excluding the degenerate specimens who live on the confines of the towns, are mainly flesh eaters and are remarkable for the excellence of their teeth ; and the same is true, to a less extent, of the white bushmen of the plains. One fact alone seems almost fatal to the view that meat is the cause of the modern increase in dental disease. In Queensland at least, especially in its tropical portion, women suffer more frequently and more severely than men, from dental caries. For some years, I examined systematically the mouths of patients, and I do not hesitate to say that in women disease commences earlier, progresses more rapidly, and attains a higher grade of destruction, than in men. The number of young girls in North Queensland, wearing com- plete sets of artificial teeth, is startling. It is unnecessary to point out that the tendency of the tropics is to spoil the appetite for animal food and to increase the taste for starches, 1 Items of Interest: A Monthly Magazine of Dental Art, Science and Literature, April, 1900. 10 sugars and fruits; and that women are notoriously more influenced in this direction than are men. § 41. We may then assume that the modern increase of dental and mouth disease is in some way connected with the modern excessive use of soft carbohydrate food-stuffs; and there can be little doubt that, if carbonaceous excess is a common food fault, it is in the main a carbohydrate excess. Shall I then be accused of straining the imaginative privileges I am claiming throughout this work, if I suggest that dental and oral disease, incurred under these conditions, are protests against improper and excessive supply? § 42. Secondary effhcts of oral disease. — As in other departments, so here, local disorganization, whether we choose to regard it as conservative or not, leads, ultimately to disor- ganization affecting remoter parts ; and we may trace a series of pathological processes from the starting-point of dental and oral diseases. The influence of imperfect mastication upon gastric digestion and general nutrition will be admitted by all. Recently, William Hunter 1 has called attention in a series of articles to 'oral sepsis as a cause of septic gastritis, toxic neuritis and other septic conditions.' And, in the 'Lancet' for August £2, L903, a case of sapraemia, due to pyorrhoea alveolaris simulating typhoid fever, is described by Dr. J. W. Carr and Mr. E. W. Roughton. GASTRIC DIGESTION. § 43. The next step in carbonization of the blood is gastric digestion. Here again efficiency will depend upon function and supply. 1. The functional capacity of the organ, of its glands and of their secretion, will depend, inter alia, upon nutrition by a due supply of proteid food. 2. The supply of material for gastric digestion concerns mainly proteid, which is the food-stuff mainly digested in the stomach. The amount will be of importance: it is easily conceivable that the functional capacity of the organ may be strained by excess of work, performed even under favourable conditions. The character of the proteid will be of the highest 1 Med. Reviezc, viii., No. 27, p. 733. 41 importance: it will have to be soft in consistence and suf- ficiently subdivided. A soft finely divided mince, made from the lean of meat, as free as possible from fat, etc., would be, on theoretical grounds, an ideal food for gastric digestion ; and practically, I know of none more readily digested. Saliva having no action upon proteid, mastication will be less neces- sary than in the case of starch foods ; but it will not be altogether superfluous, since, as pointed out by Harry Camp- bell, 1 mastication acts reflexly upon the stomach and promotes the flow of gastric juice. The conditions under which the proteid is presented to the organ, are of the greatest im- portance: they concern mainly the consistency and state of subdivision of the proteid and the presence, or otherwise, of other food-stuffs in the organ at the same time. Other things being equal, the most perfect gastric digestion will occur when all material, other than proteid, is excluded. Arguing from physiology, then, starch should be given in such a form as necessarily to undergo digestion in the mouth ; and proteid should be submitted to the gastric juice unhampered, as far as possible, by the admixture of food- stuffs, which have been undigested in the mouth, and which are indigestible in the stomach. § 44. These physiological ideals will not be found to agree with common practice. The proteid of an average meal is presented as a solid, often a very tough solid, requiring toil- some mastication to fit it for a passage through the gullet ; and our practice as regards starch foods, appears to be to hasten by all possible means their passage through the mouth, where they should be in great part at least digested, and to prolong their stay in the stomach, where their digestion is impossible. The every-day dinner of the Englishman must be regarded as highly unphysiological. Meat, insufficiently divided, is swallowed with imperfectly insalivated potatoes. As proteid digestion is commencing, the gastric juice is liable to be suddenly diluted to the point of impotence by a drench of beer or other liquid. Later, a mass of soft undigested — and. as far as the stomach is concerned, indigestible — starch, such as rice, is spread over, and mingled with, the proteid which is still only in the early stages of peptonization. 1 'Observations on Mastication,' Lancet, July 11. 1 ( .H)3, p. B5. [2 We are often advised to restrict the fluid taken during a meal on account of the danger of diluting the gastric juice, but the caution is rarely extended to slop-food in general: yet here it would seem to be even more necessary. The dilution by water is temporary: the fluid excess is rapidly passed on and absorbed, the digestion proceeds as before. But a starchy pulp is retained and hampers digestion, not only by diluting the gastric juice, but by coating the meat fibres and preventing due penetration by the digestive fluid. While thus prolonging proteid digestion, the retention of starch, useless at best, leads to abnormal fermentation, to the production of irritating organic acids, 1 and to the evolvement of quantities of gas — in short, to the phenomena of acid and flatulent dyspepsia. § 45. It is an opprobrium of medicine that theory and practice are often in conflict — that medicine is, in other words, an inexact science. The charge can hardly be denied, but I venture to submit that we are too ready to plead guilty and to ignore the instances in which theory and practice can be placed in perfect harmony. This would seem to be true, at least, of gastric dyspepsia ; for I do not hesitate to say that, were we to deduce our practice in this most common disorder from physiological principles (say from Foster's 'Text-book of Physiology'), we should in many even old-standing cases obtain rapid success. In these physiological principles, I would suggest the inclusion of the following: — 1. That good digestion implies quick digestion, and bad digestion, slow digestion. 2. That the commonest cause of slow digestion is the admixture in the stomach of unaltered starch with the proteid that is undergoing, or is about to undergo, solution by the gastric juice. 3. That proteid alone, if mechanically suit- able, is rapidly digested in the stomach. 4. That starch foods should be largely digested in the mouth. 2 1 Professor J. Bauer says : 'Since the investigations of C. Schmidt there can be no doubt that when lactic, butyric, or acetic acids are found in the stomach, they are always to be viewed as products of the decomposition of the carbohydrates of the food.' 2 These sentences were written in 1808. Since then I have often been on the point of excising them : the contained truisms seemed too obvious to be other than an impertinence in a work addressed to the medical profession. Yet as late as August, 1903, no less an authority than Harry Campbell finds it necessary to point out that starch foods 'should be given not, as is the custom, as liquid or pap, but in a form compelling vigorous mastication.' — 'Observations on Mastication,' Lancet, August 8, 1003, p. 376. 43 § 46. We arc accustomed to lay much stress upon idiosyn- crasy, especially with regard to the digestibility of various articles of diet. There can be no doubt that true idiosyncrasies exist and such should be treated with due deference. But are they anything like as frequent as we are wont to assume? 1 very much doubt it. Many alleged idiosyncrasies, on exam- ination and clinical experiment, are apt to resolve themselves into some grossly unphysiological relation between the food and the digestive organs — between supply and function. Patients, nearly always women, inform me almost daily that they are unable to digest meat. This statement, in nearly all cases, amounts to this : that meat, perhaps overcooked or badly cooked, imperfectly masticated and mixed with, or immediately followed by, a quantity of soft carbohydrate, upon which the saliva has had no time to exert any action at all, is followed by flatulence, pain and distension, whereas the omission of the meat from such a meal leads to much less discomfort. This is, of course, easy to understand. But it seems to me that it constitutes evidence of physiological, rather than unphysiological, function on the part of the stomach. And I have yet to find an instance in which a hungry stomach, unaffected with gross organic changes, is unable to digest, without morbid symptoms of any kind, meat in proper amount, properly prepared and properly presented, that is, unmixed with food-stuffs unsuited for gastric digestion. § 47. It seems to me that to excessive consumption of starch foods must be ascribed the extreme frequency of dyspeptic conditions. Clifford Allbutt says: — 'There is no superstition more tenacious of life than that which prescribes carbohydrates to all dyspeptics as so "digestible"; and into weak stomachs ready to dilate, is thrown a mass of such a dish as rice pudding — a bulky food, imperfectly insalivated and peculiarly apt to fall into decomposition with the disengage- ment of volumes of carbonic acid.' Harry Campbell 1 also animadverts strongly upon the many serious disadvantages oi tlu- modern tendency towards 'soft and pappy' food-stuffs in the dietary of both children and adults. He says:" — 'In this age of abundant starch and imperfect mastication the stomach 1 Lancet. July is, 1903. 'Observations on Mastication,' p. 152. ' Brit. Mfd. Journ., April n. L903, p. 855. 44 and intestines are flooded with undigested starch, this giving rise to many evils.' § 48. Shall we not then be justified if we regard the preva- lence of gastric dyspepsia as a protest against the commonest form of carbonaceous excess, namely, excess in soft carbo- hydrates? Such a view amounts to little more than that gastric dyspepsia results in most cases from improper food (supply) and that is not, primarily at least, due to mechanical' or chemical defects on the part of the organ (function). And it is not far removed from the view of Sir Henry Thompson, who says indigestion is mostly not a disease, but an admoni- tion. 1 Tt is the language of the stomach, and is mostly an unknown tongue to those who are addressed.' § 49. Conservative influence of gastric dyspepsia. — It will be admitted that the general tendency of dyspepsia is to restrict appetite and to limit absorption ; and if, as I shall argue later, many common affections depend primarily upon hyper- pyraemia, then it will have to be admitted that dyspepsia may play the part of a conservative process. Certain physicians throughout the history of medicine, not to mention a consider- able section of the intelligent public, have held the view that dyspepsia acts as a safeguard against greater evils. Usually, the view is restricted to the case of gout, one of the few remaining strongholds of the humoralists. Fothergill says :' — 'In plethoric gout dyspepsia is out of the question. Often, if the patient could only be rendered dyspeptic, it would be the best thing that could happen to him ; for dyspepsia would relieve him from the consequences of too much good living ("I have been a dyspeptic for fifty years," said an old clergy- man. "Thank God for it!" All his brothers had died of gout).' Gout, which I shall argue later, depends upon hyper- pyraemia, is stated by Ewart to be 'commonly acquired with the aid of a sound stomach.' We know that it is chiefly the wealthy classes who suffer from gout. Their food is of good quality: long experience in the art of cooking has led to its preparation in such a way, that immediate peptic discomfort is evaded ; it is calculated, too, to tempt the palate. Conse- 1 Lancet, November 30, 1901. ' Gout in its Protean Aspects, J. M. Fothergill, 1883, p. 111. 45 quently dyspepsia — at any rate primary dyspepsia, the variety at present under consideration — is rare: excess absorption, common. The stomach is cheated (so to speak) into passing much that it might reject, were it presented in a cruder form. As regards alcohol, it is widely recognized, that the particular variety of intemperance which makes for gout, is not irregular heavy drinking bouts, but the systematic wine bibbing which is customary amongst good livers — exactly that form of drink- ing, indeed, which is unlikely to upset digestion and unlikely to interfere with absorption. And the general tendency of high culinary art is to override and defeat the instinctive avoidance of excess, which is allowed full play under a coarse and monotonous dietary. In the case of disorders other than gout, the conservative influence of dyspepsia has been very commonly ignored; and this has led to much confusion in etiology. Most of the dis- orders and diseases to be ascribed later to hyperpyraemia, have, at different times and by various authorities, been ascribed to dyspepsia. I may here refer to asthma, migraine and some forms of skin disease. Some have regarded the dyspepsia, acting reflexly through the nervous system, as the exciting factor of the associated affection : others have regarded the dyspepsia as leading to the formation of deleteri- ous chemical substances (toxins, etc.), which, after absorption, constitute the real underlying factor in the disease ; nor are we called upon to deny the possibility of either of these modes of origin. § 50. We may, however, reconsider the whole question from a different point of view. We may take the stand that we have failed to grasp sufficiently the conservative principle of dyspepsia and have come, therefore, to restrict the influence of food in the etiology of disease to its influence in causing dyspepsia: because many disorders are preceded, or accom- panied, by dyspepsia, we have assumed that the dyspepsia is causative. And the frequent observation that many of the disorders in question are associated with no subjective or objective sign of dyspepsia, seems to have led us still farther astray. It has forced us to fall back upon one or other of the only two possibilities which seem to remain, (1) that dyspepsia may be existent, but latent; or (2) that many affections. 4.6 identical clinically, own, at different times and in different persons, fundamentally different etiologies. The prevailing uncertainty as to the relative etiological positions of food, dyspepsia and associated diseases, is voiced in the following passage from the work of a well-known author on dietetics. After referring to the usually prescribed dietetic treatment of certain forms of skin disease, the writer says :* — 'In other words these dietetic directions amount to this : if dyspepsia accompanies these disorders, the dyspepsia must be treated by the usual dietetic measures.' From a somewhat similar point of view, another author says of gout," 'the best dietary is in truth that which is most suitable for the dyspep- tic' It may be that this is usually true, but if so, it is true because a simple diet, which precludes excess, is hostile to both gout and dyspepsia : not because gout depends upon dyspepsia. In the view we here take, we admit that commonly dyspepsia precedes or accompanies many other diseases, but we explain the association by ascribing the two to a common factor, an excessive carbonaceous intake. We regard the dyspepsia as a protest against the excessive supply and as an attempt on the part of the digestive organs to prevent further intrusion of the excess into the system. The ensuing or accompanying disorder (migraine, asthma, gout, etc.), we regard as an index of the failure of these conservative meas- ures — as events arising in spite, and not in consequence, of the dyspepsia. In short, we admit that the efforts of the organism to deal with adverse conditions are successful only within certain limits. § 51. This view will I believe be found to bring into line a greater number of clinical observations than any view hitherto propounded. It will simplify our ideas of etiology; and it will explain a fact, which does not seem often to have been observed but which I am convinced is true, namely, that migraine, asthma, and many similarly induced affections, though possibly less frequent, are, other things being equal, distinctly more severe, if not more intractable, in those who possess more hearty appetites and vigorous digestions, than in poor eaters and dyspeptics. J. Combv, in an article on arthritism 1 Food in Health and Disease, 1897, p. 511 et seq. 2 Treatise on Gout, Duckworth, 1S90, p. 366. 47 in children, enumerates, and ascribes to this assumed diathesic condition, most of the affections which we are ascribing in this work to hyperpyraemia. He says: 1 — 'It has been sug- gested that most of the children suffering from symptoms enumerated are dyspeptic. On the other hand, some of the most typical gouty manifestations in children occur in those who have no dyspeptic symptom.' I am aware that the con- trary has been stated. Graeme M. Hammond 2 says of migraine : — 'All severe cases without exception are chronic dyspeptics.' I can only say that my own experience and that of numerous medical men, whom I have consulted on this point, are directly opposed to this statement ; and I cannot doubt that the total absence of all digestive troubles, in many of the severer cases of the disorders in question, has done much to perpetuate the 'primarily neurosal' fallacy (§ 286). § 52. The conservative influence of dyspepsia, when once the idea is entertained, becomes a conspicuous clinical fact : it may be seen in the alternations exhibited between dyspepsia and the affections we are ascribing to hyperpyraemia. Dr. Hawkes tells me of a man of sixty-four who consulted him for dyspepsia. He had suffered from his school days up to the age of fifty-three from 'bilious headaches' recurring once a fortnight or even once a week. About the age of fifty-three he began to suffer severely from carious teeth and pyorrhoea : as a consequence he contracted the habit of bolting his food : this soon resulted in severe dyspepsia which became chronic and has persisted ever since. He volunteered the statement that, since the commencement of dyspeptic symptoms, he has never had a bilious headache. Hyde Salter relates cases in which dyspepsia and asthma alternated, the one condition displacing and replacing the other. In one.* a little girl was subject for years to vomiting after every meal : later, the vomiting ceased, and immediately spasmodic asthma appeared: later still, the vomiting reap- peared, and again the asthma ceased. Tn this way they alternated, the vomiting always coming on when the asthma was better.' In another. 4 a girl o\ eighteen, on the death of 1 Medical Review, May. 1902, p. 873. Synopsis of article in Archives de Medicine des /infants. January and February, 1002. 3 Med. Annual. 1002, p. 426. % On Asthma. 1868, pp. 256, 257. *//>.. 48 a sister, to whom she was much attached, suddenly ceased almost entirely to suffer from long recurrent attacks of spas- modic asthma, but in place of them she became subject 'to attacks of dyspepsia, frequently causing her as much suffering and inconvenience as her previous asthma.' In my own experience, I have met with cases in which recurrent bilious attacks, and even formal migraine, alternated with constant, or frequently recurring, dyspepsia : in one, regular periodic sick headaches of some years' duration remained in complete abeyance for about eight months, during which time severe dyspepsia followed almost every meal. It may be — indeed, it seems most probable — that, in many such cases, the dyspepsia is not primary and directly due to the food, but secondary and dependent, as we shall see later (§§ 77, 78), upon glycogenic distension of the liver; but even so, these cases are still examples of the conservative influence of dyspeptic conditions. The view, we have adopted, will have an important bearing on the treatment of the dyspepsia in these cases. Treatment, addressed solely to the suppression of the discomfort attending the gastric disorder, may possibly turn out to be injurious in proportion to its success ; and treatment, which, by means of artificial digestive ferments or other agents, increases the absorption which the gastric revolt is adapted to diminish, will certainly be so. Therapeutic interference will have to be limited strictly to the removal of the common cause. § 53. Secondary effects of gastrtc dyspepsia. — Although we may fully subscribe to the view that gastric dyspepsia is often a protest against improper or excessive food and con- servative against the results of excessive absorption (c. g. hyperpyraemia), yet we must admit that long recurrent and unheeded protests, here as elsewhere, tend to local stress and disorganization ; and that such local damage may constitute the starting-point of a series of secondary disorders and dis- eases affecting the system generally. Nor shall we be called upon to modify these views if we find that some of these secondary pathological conditions are more serious or more fatal than those which, we are assuming, the gastric protest is adapted to avert ; for the conservative measures of the organ- ism are not restricted to such as are economical in their operation (§§ 921 to 924). 49 A few of the pathological conditions, which may take their starting-point from gastric dyspepsia, may here be referred to. Reflex disturbances, such as some forms of headaches: catarrhal conditions of the mucous membrane: gross structural changes, such as glandular and other degenerations, dilatation, possibly ulcer: various forms of malnutrition; and probably some anaemias. We may freely admit the possibility that dyspepsia may lead to the formation of abnormal or toxic compounds which after absorption may exercise deleterious influences upon the economy; but this will not preclude us from ascribing a long list of well-known nervous and other disorders such as migraine, asthma, epilepsy, angina and many more, to hvperpvraemia. INTESTINAL DIGESTION AND DYSPEPSIA § 54. We know that the process of digestion continues after the contents of the stomach have escaped from the pylorus. The chyme is now brought under the influence of the bile, the pancreatic and intestinal juices, and its various constituents modified still further to fit them for absorption by the blood-vessels and lacteals. In all probability, the digestive processes occurring in the intestinal canal are at least equally important with those occurring higher in the alimentary tract; and it is certain that absorption occurs here to a far greater extent than heretofore. Intestinal digestion, however, is much more complicated and much more obscure than digestion in the mouth and stomach ; and the same is naturally true of intestinal dyspepsia. But we may, 1 think, apply to it the same general principles as to primary digestion elsewhere. The efficiency of the process will depend upon (1) supply, and (2) function. 1. The supplied material comprises the more or less digested contents of the stomach: the suitability of these for intestinal digestion and absorption will depend largely upon the efficiency of digestion in the oral and gastric cavities, and indirectly therefore upon all the factors which govern these latter, such as proteid supply, etc. 2. The functional capacity of the intestinal canal, concerns its mechanical, chemical and physiological actions: these will depend no doubt upon a multitude of factors, but inter alia, 00 upon nitrogenous nutrition and therefore, upon a due supply of proteid. Consequently, that part of the process of carbonization of the blood, which consists of digestion and absorption in the intestinal canal of carbonaceous material (for it is only the carbonaceous material which now concerns us), will depend in no small degree upon the supply of proteid in the food. We shall expect therefore to be able, in some cases, to increase carbonization by increasing the supply of proteid, in others to decrease carbonization by decreasing the supply of proteid. EVIDENCE THAT CARBONIZATION OF THE BLOOD IS A VITAL ACTION AND DEPENDS ON THE SUPPLY OF PROTEID § 55. The a priori arguments, advanced in favour of the view that carbonization of the blood is a vital action and is condi- tioned by the supply of proteid in the food, are well supported by experimental and other data. It is well known, as Foster 1 points out, that 'when an animal is fed simply on non-nitrog- enous food, death soon takes* place; the food rapidly ceases to be digested, and starvation ensues.' The cessation of diges- tion is not, of course, immediate ; otherwise no meal, from which proteid is excluded, would be of any nutritive value whatever. For a time after the complete withdrawal of pro- teid, the efficiency of the digestive mechanism, solid and fluid, is maintained, doubtless at the expense of the nitrogen of the body derived from previous proteid intake. But the subse- quent failure is rapidly progressive. The above experiment shows that fresh proteid intake is essential to the continued carbonization of the blood ; it does not, how r ever, give any idea of the minimum amount of fresh proteid which is essential. But it is fair to infer that carbonization would increase with the supply of proteid up to a certain point. § 50. Under an ordinary mixed diet, the carbonaceous con- tents of the alimentary canal include the carbohydrates, the carbonaceous portion of the proteids and the fats. The former two pass probably by the portal blood-vessels to the liver, where some of the carbohydrates at least are in part temporarily stored as glycogen. Now it is admitted that 'of 2 1 Text-book of Physiology, 1895, p. 833. 2 lb., M. Foster, 1895, p. 751. 51 the three great classes of food-stuffs, the carbohydrates stand out prominently as the substances which, taken as food, lead to an accumulation of glycogen in the liver' (Foster). But 'a 1 quantity of carbohydrate mixed with a certain proportion of proteid gives rise to a larger amount of glycogen in the liver than the same quantity of carbohydrate by itself (Foster). And it is reasonable to explain this experimentally demonstrated fact by ascribing to the added proteid some power to assist in the digestion and absorption of the carbo- hydrate. But if this is true, then the carbonization of the blood by carbohydrates will be dependent largely upon the proteid supply. § 57. Against this conclusion, it might perhaps be argued that, since many persons consume but a very small amount of proteid, carbohydrate should often appear undigested in the faeces ; and it is asserted that 'in ' health the carbohydrate food that is eaten does not appear in the faeces.' But Herter* points out that 'the fact that there is no soluble carbohydrate material in the faeces does not enable us to infer that it is all absorbed and utilized. Even in health there is always some waste of energy and potential from the fermentation of the carbohydrates' ; and it is natural to believe that a retardation of digestion and absorption, brought about by a reduction of the proteid intake, would be fraught with an exaggeration of such fermentative processes and by a consequent increased loss of energy and potential. Further, the statement that carbo- hydrates do not appear in the faeces is not exclusively true. As Herter says,* 'a frequent peculiarity of patients who are receiving an excess of starchy carbohydrate is that the faeces show the effect of this excess by the presence of undigested starch.' § 58. There is ample evidence to show that the digestion and absorption of fats (the carbonization of the blood by fats), depends, in great part, upon the supply of fresh proteid in the food. It will be admitted that the secretion of the bile is largel) dependent on the supply of proteid. '11. Nasse" . . . saw ... a great increase of the secretion of bile, when with fat 1 lb. p. 751. 'Chemical Pathology, Herter, p. 41. % lb. p. 41. *'h. L902, p. 49. 'Quoted by J. Milner Fothergill, Indigestion and Biliousness, vol. i. p. 170, Lfi 52 nitrogenous foods were also given. Ritter found that, in a dog fed only on potatoes, or on potatoes and fat only, the amount of bile daily excreted fell very low.' And 'Bidder 1 and Schmidt . . . noticed that, upon an exclusive diet of fat, the secretion of bile at once fell to the level of that in an animal from whom all food was withdrawn.' Less conspicuously, the same occurs in the human subject. Those, who have experimented clinically with various diets, know that, under a diet markedly deficient in proteid, bile is deficient from the motions, which are large, pale and usually dry ; and that, on the other hand, under a diet of nearly pure proteid, as for example the Salisbury diet, bile is in excess in the motions, which are small, dark and usually moist. In the first case, the amplitude of the evacuations may be taken to indicate deficient absorption : in the second, the opposite condition, to indicate the contrary. The excessive bile formation in the second case may explain a fact which I have often observed, namely, that, under a lean meat diet, even in the presence of constipation, the dose of any aperient required to cause purgation is much less than under other dietaries. From all this it might be — indeed it often has been — inferred that the bile is manufactured out of the proteid of the food, rather than out of the fats and carbohydrates. But this is no necessary inference. We know that bile formation is a function of the hepatic cells and that these, like all functionally active tissues, are nitrogenous. Hence we have the right to infer that the cessation of bile secretion, which follows withdrawal of proteid, is due. in great part at least, to a failure of function, rather than to a failure of supply; and we may hold this view without denying that the constituents of bile are in part derived from the proteid ingesta. But, be that as it may, there is no question that the absorption of fat is largely dependent on the supply of bile to the intestinal canal. Bidder and Schmidt demonstrated this experimentally. 'A ' dog, which in its normal condition absorbed on an average seven grains of fat for every two pounds of its weight, absorbed only three grains, or even as little as one grain, after the bile was prevented entering the intestines l Ib. ■ Treatise on Diseases of the Liver, George Harley, 1883, p. 87. 53 in consequence of a ligature being applied to the gall duct.' These observers found also 'that 1 while the chyle in the thoracic duct of a healthy dog contains thirty-two parts of fat per thousand, that in the thoracic duct of a dog with a ligatured gall duct contains only two parts per thousand.' In man, the influence of the bile in promoting the absorption of fats, may be inferred from observations on the faeces. Herter* says :— 'Normally the faeces contain a considerable proportion of fat'; but, in cases of jaundice, this proportion tends to increase. Hence it is clear that the ingestion of proteid, through dominating bile formation, dominates also in great part the car- bonization of the blood by fats. § 59. Finally, what is true of carbonization by carbohydrates and fats, is in all probability true of carbonization by proteids — that is to say, the digestion and absorption of proteids depends upon nitrogenous nutrition and this upon the proteid intake. And what is true of the digestion and absorption, which it effected, directly or indirectly through the action of the saliva, gastric juice and bile, is doubtless true of the digestion and absorption which follows the action of the pancreatic and intes- tinal juices. § GO. The actual process of digestion may be in the main chemical; but the manufacture of the chemically active juices is a vital action. Hence digestion, as we have argued, depends primarily upon due nutrition by proteid. Of absorption, the same is true. B. Moore says: 8 — 'It was for many years believed that the absorption of the products of digestion from the alimentary canal was governed by exactly the same physical laws as determine the passage of a solution through an inert membrane, but the accumulation of experimental evidence has rendered such a belief no longer tenable. It is now known that the cells which line the alimentary canal take an active part, not only in absorbing the materials prepared for them by the action of the digestive secretions, but in modifying these products in various ways during the process.' Thus absorption, as well as digestion, depends upon an active or vital capacity of the nitrogenous cells; and it is open for us to regard every 1 lb. p. i * Chemical Pathology, 1902, p. • Text-book of Physiology, SchatVr, 1898, vol. i. p. 431, step in the complex process of carbonization as dependent, more or less directly, upon nitrogenous nutrition and, therefore, upon the supply of proteid in the food. SUMMARY. § 61. In this chapter, I have attempted to show that the carbonization of the blood — the supplying of the blood with unoxidized carbonaceous material, or fuel — is a complex chemico-vital function of the nitrogenous tissues of the digestive organs, and that it depends, inter alia, upon a due supply of proteid in the food : that some functional disorders, for example, dyspepsia, and even some structural diseases, for example, dental caries, may sometimes be regarded as conserva- tive against hyperpyraemia, inasmuch as they tend to restrict the carbonization of the blood : that many general diseases do not, as so often assumed, depend upon dyspepsia, but own with it a common factor in an excess of carbonaceous food; and that some functional disorders and structural diseases, though immediately conservative, often form the starting-points of secondary pathological processes. L.ofC. DO 'v FED 13 1905^ V ,\ LBJ'_ *0j )\ w ni ^ 1 • s s / ^ c . < y. 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