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 FISHERY BOARD FOR SCOTLAND, 
 SALMON FISHERIES. 
 
 REPORT 
 
 OF 
 
 INVESTIGATIONS 
 
 OX THE 
 
 LIFE HISTORY OF SALMON. 
 
 presented to parliament bp Command ot 1ber /lfcajest. 
 
 GLASGOW : 
 PRINTED FOR HER MAJESTY'S STATIONERY OFFICE 
 
 BY JAMES HEDDERWICK & SONS, 
 AT "THE CITIZEN" PRESS, ST. VINCENT PLACE. 
 
 And to be purchased either directly or through any Bookseller, from 
 JOHN MENZIES & CO., 12 HANOVER STREET, EDINBURGH, and 
 
 90 WEST NILE STREET, GLASGOW ; or 
 
 EYRE & SPOTTISWOODE, EAST HARDING STREET, FLEET STREET, E.C. ; or 
 HODGES, FIGGIS & CO., LIMITED, 104 GRAFTON STREET, DUBLIN. 
 
 1898. 
 ~C. 8787.] Price Is. lid.
 
 FISHERY BOARD FOR SCOTLAND, 
 EDINBURGH, 23rd February, 1898. 
 
 SIR, 
 
 I am directed by the Fishery Board for 
 Scotland to transmit herewith a Eeport of Investigations 
 into the Life-History of Salmon in Fresh Water, which 
 was submitted to the Board at a meeting held on 18th 
 instant, and ordered by them to be forwarded to you, 
 for the information of the Secretary for Scotland. 
 
 I have the honour to be, 
 
 SIR, 
 Your most obedient Servant, 
 
 WM. C. KOBEKTSON, 
 
 Secretary. 
 
 The Under-Secretary for Scotland.
 
 
 REPORT OF INVESTIGATIONS 
 
 LIFE-HISTORY 
 
 SALMON IN FRESH WATER: 
 
 FROM 
 
 THE RESEARCH LABORATORY OF THE ROYAL COLLEGE 
 OF PHYSICIANS OF EDINBURGH. 
 
 E D 1 T E D B Y 
 
 D. NOEL iPATON, M.D., 
 
 SUPERINTENDENT OF THE LABORATORY. 
 
 GLASGOW: 
 
 KD HY JAMES HEDDERWICK & SONS, 
 TiiK CITI/.KN" I'RKKS, ST. VINCENT PLACE.
 
 RESEARCH LABORATORY OF THE ROYAL COLLEGE OF 
 
 PHYSICIANS OF EDINBURGH, 
 
 January, 1898. 
 
 To THE SCOTTISH FISHERY BOARD. 
 GENTLEMEN. 
 
 I have the honour to present the following- Report 
 of the Investigations on the Life-History of the Salmon in Fresh 
 Water, which have been carried 011 in the Research Laboratory of 
 the Royal College of Physicians of Edinburgh. 
 
 In doing so, I desire to state that the valuable plan of procuring 
 salmon simultaneously from the mouths and from the upper reaches 
 of the rivers for the investigation of the migrations of the fish and 
 the elucidation of the question of whether fish leaving the sea early 
 in the year remain in the upper waters until the breeding season, 
 is due to Mr. Walter E. Archer. Inspector of Salmon Fisheries for 
 Scotland. 
 
 On behalf of my fellow-workers and myself, I take this oppoi'- 
 tunity of thanking him for much valuable advice and assistance 
 during the prosecution of the work. 
 
 I have the honour to be, Gentlemen, 
 
 Your obedient Servant, 
 
 D. NOEL PATON, 
 
 Superintendent of the Laboratory of the Royal 
 College of Physicians of Edinburgh.
 
 SH 
 
 CONTENTS. 
 
 I. INTRODUCTORY. 
 
 1. General Introduction. By D. Noel Paton, M.D., B.Sc., 
 
 F.R.C.P.Ed., Superintendent of the Laboratory, - 1 
 
 2. How far may the Salmon examined be considered 
 
 typical of their respective classes. By Walter E. 
 Archer, Esq., F.R.S.Ed., Inspector of Salmon 
 Fisheries for Scotland, - 9 
 
 II. -THE SOURCE FROM WHICH SALMON OBTAIN NOURISHMENT, AND 
 THE EXCHANGES OF MATERIAL IN THE BODY DURING THEIR 
 SOJOURN IN FRESH WATER. 
 
 A. The Power of the Alimentary Canal to Digest and Absorb 
 Food. 
 
 3. The Minute Structure of the Digestive Tract of the 
 
 Salmon, and the Changes which occur in it in 
 Fresh Water. By G. Lovell Gulland, M.A., B.Sc., 
 M.D., F.R.C.P.Ed., 13 
 
 4. Changes in the Digestive Activity of the Secretions of 
 
 the Alimentary Canal of the Salmon in different 
 conditions. By A. Lockhart Gillespie, M.D., 
 F.R.C.P. Ed., 23 
 
 5. Bacteriology of the Alimentary Canal of the Salmon in 
 
 different conditions. By A. Lockhart Gillespie, 
 M.D., F.R.C.P. Ed., 36 
 
 B. Changes in the Weight and in the Constituents of the 
 Muscles, Genitalia, and other Organs during the 
 sojourn of Salmon in Fresh Water. 
 
 6. Changes in the Weight and Condition of Salmon 
 
 at different seasons in the Estuaries and in the 
 Upper Reaches of the River. By D. Noel Paton, 
 M.D., F.R.C.P.Ed., Miid J. C. ' Dunlop, M.D., 
 F.R.C.P.Ed., - 63 
 
 Chemical Changes Preliminary Considerations. By D. 
 Noel Paton, M.D., F.R.C.P.Ed., - 79 
 
 7 The Changes in the Solids and Water of Muscles and 
 Genitalia in the Salmon in Fresh Water. By D. 
 Noel Paton, M.D., F.R.C.P.Ed., - 83
 
 8. The Changes in the Fats of Muscle, Genitalia, and other 
 
 Organs of the Salmon in Fresh Water. By D. 
 Noel Paton, M.D., F.R.C.P.Ed., - 93 
 
 9. Microscopical Observations 011 the Muscle Fat in the 
 
 Salmon. By S. C. Mahalanobis, B.Sc., F.R.M.S., 106 
 
 10. The Nature of the Proteids, of Salmon Muscle. By 
 
 Francis D. Boyd, M.D., F.R.C.P. Ed., - 112 
 
 11. The Changes in the Amount of Proteid in the Muscula- 
 
 ture and Genitalia of the Salmon in Fresh Water. 
 
 By James C. Dunlop, M.D., F.R.C.P.Ed., 120 
 
 12. The Fats and Proteids stored in the Muscle of the 
 
 Salmon considered as a source of Muscular Energy. 
 By D. Noel Paton, M.D., F.R.C.P.Ed., 139 
 
 13. The Phosphorus Compounds of the Muscle and Genitalia 
 of the Salmon, and their Exchanges. By D. 
 Noel Paton, M.D., F.R.C.P.Ed., - 143 
 
 14. The Exchanges of Iron between the Muscles and 
 
 Ovaries of the Salmon in Fresh Water. By E. D. 
 
 W. Greig, M.B., Ed., - 156 
 
 15. The Pigment of the Muscles and Ovaries of the Salmon 
 
 and their Exchanges. By M. I. Newbigin, B. Sc., 159 
 
 16. The Changes in the value of the Salmon as a Food Stuff. 
 
 By James C. Dunlop, M.D., F.R.C.P. Ed., 165 
 
 III. SUMMARY OF RESULTS. 
 
 17. General Summary. By D. Noel Paton, M.D., 
 
 F.R C.P.Ed. -"-.-_. 169
 
 INVESTIGATIONS ON THE LIFE-HISTORY OF 
 THE SALMON IN FRESH-WATER. 
 
 I. INTRODUCTORY. 
 
 1. GENERAL INTRODUCTION. 
 
 BY D. NOEL PATON, M.D., F.R.C.P.ED., B.Sc. 
 SUPERINTENDENT OF THE LABORATORY. 
 
 THE curious life history of the salmon has always been a subject of the 
 deepest interest not only to the zoologist and physiologist bu1; also to 
 the sportsman and the fisherman. In spite of the most careful study 
 by scientific investigators, the migrations of the salmon and the various 
 changes in condition which it undergoes are even now far from being 
 fully understood, and the careless observations and foolish traditions 
 of keepers, fishermen, and ghillies have only served to involve the 
 matter in a deeper cloud of mystery. 
 
 Only a few years ago the processes of reproduction and develop- 
 ment were matters of speculation, and many of the older writers 
 indulged in the most fanciful ideas upon these points. The investi- 
 gations and experiments of Sir James Maitland and others have 
 supplied the required information, and the reproduction and develop- 
 ment of the salmon are no longer mysteries. 
 
 But many other questions in its life history remain unsolved. Yearly, 
 or at longer intervals, the fish appear on our coast, apparently from the 
 deeper waters, and ascend the rivets, there, somewhere between 
 October and January, to deposit their spawn and milt. Having done 
 so they descend the river as " kelts," and again disappear in the sea, 
 to return either in the same or in the following year to the fresh water. 
 
 What force urges the fish to leave its rich feeding ground in the sea ? 
 Is it necessary that it should enter fresh water in order to perform 
 the act of reproduction 1 Does it require or procure any food during its 
 sojourn in the river, and, if not, how is it able to maintain life and to 
 construct its rapidly growing genital organs '( 
 
 In the female the growth of these is enormous. In April or May the 
 ovaries constitute only about 1*2 per cent, of the weight of the fish in 
 November they are no less than 23'3 per cent. In a fish of 301bs. in 
 the spring they weigh about 120 grms. in November they weigh
 
 2 Investigations on the Life History 
 
 over 2000 grrus. The increase in the testes in the male is not so marked, 
 but is sufficiently striking. In April or May these organs are about 
 0-15 per cent, of the weight of the fish, while in November they are 3'3 
 per cent. 
 
 From what are these structures formed ? As they grow, the muscle, 
 as is well known, undergoes marked and characteristic changes. Not 
 only does it diminish in amount as the season advances, so that the fish 
 which have been some time in the river become smaller in the shoulder 
 and back, but it loses its rich, fatty character, while it becomes paler in 
 colour. 
 
 Are these changes in the muscle connected with the growth ot the 
 ovaries and te*tes ? And if so, in what manner and to what extent ? 
 
 On the other hand, in fighting its way up rapids and over falls an 
 enormous amount of muscular work is accomplished by the salmon. 
 Whence is the energy for this work obtained ? Are the changes in the 
 muscle connected with the performance of this work, and if so to what 
 extent are these changes connected with the muscular work, and to what 
 extent with the growth of the genitalia. Lastly, the question arises 
 to what extent do these changes in the muscle modify the value of the 
 flesh as a food stuff. 
 
 In the investigation of some of these questions most excellent work 
 has already been done, not only in Holland and Germany upon the 
 salmon in the Rhine by Dr. Hoek* and Professor Miescher Ruesch,t 
 but also by Mr. Archer, the Inspector of Salmon Fisheries for Scotland, 
 in conjunction with Mr. Grey and Mr. Tosh. The careful series of ob- 
 servations embodied in the Annual Reports J are well worth careful study 
 by the zoologist and the salmon fisher. They should help to dispel 
 the absurd traditions which cling around the history of the salmon, 
 and to pave the way for the complete solution of many of the problems 
 we have enumerated. 
 
 The present investigation is a continuation and amplification of these 
 researches, and would have been impossible without these previous 
 laborious studies. 
 
 Briefly stated, these investigations of the Fishery Board have estab- 
 lished the following facts : 
 
 1st. That some salmon spawn every year, though there is strong 
 evidence that all do not do so. (Eleventh Annual Report, Part If., 
 p. 68.) 
 
 2nd. That the genitalia of fish coming from the sea develop steadily 
 from April on to the spawning time, and that the genitalia of salmon 
 in the earlier summer months develop more rapidly than those of grilse. 
 (Fourteenth Annual Report, Part II., pp. 15 and 21.) 
 
 3rd. That the proportion of the weight of genitalia to the weight of 
 the fish is constant for all sizes of salmon. (Fourteenth Annual Report, 
 Part II., p. 11.) 
 
 4th. That salmon continue to feed while in the sea until September. 
 This is shown, firstly, by the presence of food in the stomach of a certain 
 proportion of the fish captured (Fourteenth Annual Report, Part II., pp. 
 77 to 80.) ; and secondly, by the fact that the fish leaving the sea are 
 somewhat heavier from 2 to 3 per cent. in August and September 
 than they are in the earlier months, whereas if they had entirely stopped 
 
 * Rapport over Statistische en biologische onderyoekingen ingesteld mett behulp van in Neder- 
 land gevangen Zalmen. Dr. P. V. C. Hoek, Wetei.schappelijk Adviseur in Visscherijzaken. 
 
 t Statistische und biofogtache Beitrage zur Kenntniss von Leben des Rheinlachses im Susswasser 
 Dr. F. Meischer Ruesch, Prof. d. Physiol. in Basel. A contribution to the literature of the Berlin 
 Fisheries Exhibition of 1880. Publishers, v^on Metrger & Wiltijr, Leipsic. feee also Histocluinis- 
 che , und Phvsiol gischen Arbeiten von Friedrich Miescher. Bd II. s. 116. Leipzig, 1897. 
 
 t Appendices to Thirteenth and Fourteenth Annual Reports of the Fishery Board for Scotland,
 
 of the Salmon in Fresh Water. 3 
 
 feeding they should have been lighter. (Fourteenth Annual Report, Part 
 //., ,>. 12.) 
 
 If salmon do feed in the sea it is perhaps curious that food should be 
 found in so small a percentage of those captured at the mouths of 
 rivers. But it must be remembered that the estuary of the river is not 
 the natural feeding ground of the salmon, and it is probably only by chance 
 that food is still in the stomach of fish captured there. 
 
 SCOPE OF PRESENT INVESTIGATION. 
 
 The present investigation was undertaken with the following 
 objects : 
 
 1. To throw light upon the influences determining the migration of 
 salmon from sea to river and from river to sea, and to study more fully 
 than has hitherto been done the course of the migrations. 
 
 2. To investigate whether salmon in fresh water require or use food; 
 and whether fish which do nob leave the sea till late in the autumn 
 continue to feed while their genitalia are developing ? 
 
 o. To study the relative rate of growth of genitalia in salmon in fresh 
 water and in the sea. 
 
 4. To investigate more fully the nature of the changes in the flesh 
 (muscle) and genital organs throughout the year. 
 
 5. To determine the source of the material used in the construction 
 of the genital organs, and to study the chemical changes which the 
 various substances undergo. 
 
 6. To elucidate the source of the energy required by the fish in 
 ascending the river. 
 
 METHOD OF INVESTIGATION. 
 
 To cany out this enquiry, it was necessary to have a supply of fish at 
 all possible seasons of the year. Further, it was desirable to have fish 
 from different sources at these various times some from the sea at the 
 mouth of the river, some from the upper reaches so that the changes of 
 the fish in their passage up the river, and in their sojourn in the upper 
 waters, might be thoroughly studied. 
 
 It is known that through the spring, summer, and autumn there is a 
 more or less constant procession or stream of salmon passing from the 
 sea into the rivers. Our plan, then, was to take samples of the fish just 
 leaving the sea, and similar samples of those which had reached the 
 upper parts of the livers, and, by comparing the latter with the former, 
 to investigate the changes which had taken place during the sojourn of the 
 fish in fresh water. The method may be compared to that of taking 
 samples of water from two parts of a river in order, by examination of 
 them, to ascertain what changes have taken place in the water 
 between these points. 
 
 MATERIAL FOR INVESTIGATION. 
 () Supply of Fish. 
 
 The observations were commenced in June 1895 at the request of Mr. 
 Archer, Inspector of (Salmon Fisheries for Scotland. 
 
 At this time Mr. Tosh was stationed at Berwick-on-Tweed investi- 
 gating the growth of the genitalia in Tweed salmon, and it was arranged 
 that he should send the viscera, with portions of the flesh, to the 
 Laboratory. 
 
 It was soon found that to make the investigation satisfactory it would
 
 4 Investigations on, t/te Life- History 
 
 be necessary to determine the precise amount of muscle on the fish, and 
 since this was impossible in the fish required for market, Mr. 
 Johnston, of Montrose, was approached by Professor Macintosh, of 
 St. Andrews, and, at his own expense, supplied a series of salmon caught 
 in his fishings on the North Esk throughout the season. 
 
 The material so accumulated and examined yielded results of consider- 
 able interest, but clearly showed that, to make the investigation 
 complete, a more extensive supply was necessary. Further, Mr. 
 Archer's Report to the Fishery Board for 1895 showed that in any such 
 investigation results obtained from grilse could not with safety be applied 
 to salmon. For this reason it was resolved to exclude grilse from 
 the investigation. 
 
 Mr. Archer threw himself into the progress of the enquiry with 
 enthusiasm, and, a grant having been obtained from the Fishery Board 
 to defray the expenses of collecting material, he made arrangements for a 
 large supply of fish throughout the season of 1896. 
 
 To thoroughly check and control observations, it was arranged to 
 procure salmon from different rivers, and the Helmsdale, Spey, Dee, 
 and Annan were selected. 
 
 It was further arranged that fish should be supplied first from the 
 mouth of each river, and second from the upper reaches. 
 
 Through the liberality of the various proprietors the Duke of 
 Richmond, the Duke of Sutherland, the Duke of Fife, the Dee 
 (Aberdeenshire) District Board, Mr. Mackenzie of Newbie, and the 
 late Mr. Heywood-Lonsdale, the following supply of material was 
 obtained : 
 
 1895. 
 
 From Mr. Johnston, of Montrose, 10 male and 9 female salmon and 
 grilse were received. 
 
 From Mr. Tosh, at Berwick-on-Tweed, and later at Melrose, the 
 viscera and a portion of the muscle of 18 fish were obtained. 
 
 Four whole salmon were late in the year received from the upper 
 waters of the Tweed through the courtesy of the Police Committee of 
 the Commissioners of the River. 
 
 1896. 
 
 On March 6th the viscera of seven salmon captured at the mouth of 
 the Tweed were procured at Berwick. 
 
 From May to November 69 salmon were received from the various 
 stations as follows : 
 
 
 May-June. 
 
 July-Aug. 
 
 Oct.-Nov. 
 
 Helmsdale. 
 Spey, 
 Dee, 
 
 | Mouth, 
 i Upper, - 
 J Mouth, 
 1 Upper, - 
 J Mouth, 
 ! Upper, 
 
 3 
 3 
 4 
 3 
 5 
 3 
 
 2 
 4 
 6 
 
 5 
 
 5 
 
 1 
 5 
 3 
 1 
 5 
 3 
 
 Annan, - 
 
 J Mouth, 
 \ Upper, - 
 
 4 
 
 4 
 
 
 Totals, 
 
 25 
 
 26 
 
 18 
 
 [n the spring of 1897, 22 kelts were received from the Spey.
 
 of the Salmon in Fresh Water. 5 
 
 In drawing conclusions from the study of this material one question 
 must be considered. How far do fish captured in the upper waters 
 actually represent the condition of all the fish there ? These fish were 
 for the most part taken with the fly, and it is the common opinion of 
 anglers that fresh-run fish take the lure more readily than those which 
 have been in the water for some time. It is thus possible that the fish 
 procured from the upper waters do not fairly represent the general 
 condition. Fortunately at Kiiicraig, on the Spey, the fish were taken 
 with the net, and an examination of the various tables shows that they 
 do not differ from the fish taken with the rod in the upper reaches of 
 the other rivers. 
 
 (/>) Preparation and Preservation of Matwial. 
 
 The duty of examining and preparing the fish as they were received 
 in the Laboratory was discharged by Mr, Alfred Patterson, one of the 
 assistants, who had had a special training in analytic chemistry, and his 
 work was supervised by me. 
 
 The external appearance of the fish was observed, and the presence of 
 sea lice, ulcers, wounds, &c., noted. 
 
 The fish was then measured as follows : Length from mouth to fork 
 of tail, depth at anterior border of dorsal fin, and girth at the same 
 place. It was next weighed. The skin covering the trunk muscles on 
 one side was next carefully removed, along with the anal firi of that 
 side, any adherent flesh being afterwards carefully picked off and placed 
 along with the rest. The skin was weighed. 
 
 The great trunk muscles on the same side were then carefully 
 separated from the bones, and weighed. In some cases the " thin " 
 belly muscle was separated from the " thick," and weighed separately. 
 It was soon found that the " thin " was about a quarter of the whole 
 muscle, and separate weighings were therefore discontinued. 
 
 Pieces of the " thick " and of the " thin," of about 30 grms. each, taken 
 at the level of the anterior edge of the dorsal fin, were preserved in 
 spirit. Another portion of fie " thick " was weighed, and pounded up 
 with an equal quantity of common salt. 
 
 The abdominal cavity was now opened, arid the viscera, with the 
 exception of the heart, the ovaries or testes, and the kidneys were 
 removed and weighed. The liver was separated from the other viscera, 
 and the condition of the gall bladder was noted. The gall bladder was 
 removed and the liver weighed. A weighed portion of the organ 
 about 30 grms. was put in methylated spirit. 
 
 In many cases inoculations upon gelatin were made from the stomach, 
 pylorus, and intestine for the investigation of the bacteriology of the 
 alimentary tract. 
 
 The stomach and intestine were opened, and the characters of the 
 contents noted. Small pieces of stomach, intestine, pyloric appendages, 
 and liver were in many cases placed in perchloride of mercury, and 
 pieces of the liver were sometimes fixed in osmic acid for microscopic 
 examination. 
 
 The stomach and oesophagus were cut off from the lower part of the 
 alimentary canal, and were placed in alcohol. The pyloric appendages, 
 with the intestine, were placed in alcohol in a separate bottle. 
 
 The ovaries or testes were now removed and weighed, the latter being 
 weighed without the ducts, which were cut off' close to the organs. 
 Pieces of the organs, of about 30 grms., were preserved in methylated 
 spirits. 
 
 The rest of the fish, consisting of the head, heart, vertebral column, 
 kidneys, tail, fins, and the muscles of the other side, were weighed.
 
 6 Investigations on the Life-History 
 
 From these weighings the total weight of muscle and the weight of 
 "thick" and "thin" could be calculated, as shown by the following 
 example from the Receiving- Book : 
 
 No. 23. Aberdeen, 27th May 1896. 
 From Maidh of the Dee. 
 
 Clean fish. Sea lice. Stomach empty. Intestine contained yellow 
 mucus and tape-worms. Pyloric appendage coated with fat. Gall 
 bladder distended. 
 
 Length, 67 cm. Girth, 36'5 cm. Depth, 15 cm. 
 
 Weight, 3,425 grms. 
 
 of Skin on one side, . . . 110 grms. 
 
 of Viscera, 103 grms. 
 
 of Ovaries, 16 grms. 
 
 of Trunk Muscle of one side, . 1,087 grms. 
 
 of Rest of Fish, .... 2,005 grms. 
 
 The weight of the trunk muscles was thus 2174 grms., and of this 
 a quarter, or 543, was "thin," and the remainder, or 1631, was 
 "thick." 
 
 (c) Method of comparing Fish of different sizes. 
 
 In dealing with this mass of material the first question which had to 
 be considered was how to make the results obtained from one fish 
 comparable with those obtained from another. The fish received varied 
 in length from 66 to 108 cm., and in weight from 2675 to 12,670 grms. 
 To compare the various parts of a fish of 3000 grms. with one of 10,000 
 grms. it is obviously necessary to reduce the results to some common 
 measure. 
 
 In previous observations the weight of the various organs has usually 
 been expressed simply as a percentage of the total weight of the fish ; 
 but, if the changes in substance of two structures such as the muscle and 
 ovaries one of which steadily loses weight while the other steadily, gains 
 it are to be compared, obviously to calculate the changes in muscle, in 
 terms of the weight of the fish, will give a fallacious idea of the extent 
 of these changes. 
 
 A more constant standard is the length of the fish, and in his 
 Annual Report, No. 14, 2-12, Mr. Archer has used this standard. 
 
 But the weight of the fish varies not as its length but as some factor 
 of its length approaching the cube, on the rule that two bodies of similar- 
 shape and of the same material vary as the cube of their length or some 
 like dimension. Thus a fish of 100 cm. in length is not twice as heavy 
 as a fish of 50 cm., but is eight tunes as heavy. On trial, in a large 
 number of cases of fish of different sizes, it was found that the cube 
 gave satisfactory results, and it was therefore adopted as the factor. 
 
 The standard length, or unit of length, selected was 100 cm. the 
 ordinary length of a salmon of about 301bs. This was selected simply 
 because it yielded convenient figures. 
 
 To obtain the weight per unit of length the proportion thus is : 
 
 Actual length, cubed : standard length, cubed : f actual weight : x. 
 
 Table I. shows the correspondence of the results obtained in this 
 way with the actual weights observed in the very large number of fish 
 included in Table XIV., p. 27 of Vol. XIV. (1896) of the Fishery 
 Board Reports, Part II.
 
 of the Salmon in Fresh Water. 
 TABLE I. 
 
 Length. 
 
 Weight. 
 
 Cube 
 Calculation. 
 
 Average 
 of Actual 
 Weights. 
 
 May. 
 
 June. 
 
 July. 
 
 Aug. 
 
 Sept. 
 
 75 
 
 4289 
 
 4133 
 
 3707 
 
 4533 
 
 4333 
 
 4219 
 
 4199 
 
 76 + 
 
 4324 
 
 4409 
 
 4503 
 
 4458 
 
 4653 
 
 4390 + 
 
 4469 
 
 77 + 
 
 4666 
 
 4577 
 
 4644 
 
 4817 
 
 4462 
 
 4565 + 
 
 4633 
 
 79- 
 
 4706 
 
 4982 
 
 4804 
 
 5018 
 
 5355 
 
 4930- 
 
 4973 
 
 80 
 
 5160 
 
 5013 
 
 5249 
 
 5333 
 
 5129 
 
 5120 
 
 5181 
 
 I am indebted to Mr. Archer for the following observations on this 
 point, made upon a very large series of fish of different lengths : 
 
 TABLE II. 
 
 Length in Cm. 
 
 No. of Fish 
 Examined. 
 
 Average Weight 
 in Grms. 
 
 Weight for Fish of 
 Standard Length. 
 
 70-0 
 
 102 
 
 3311-2 
 
 9716 
 
 79-0 
 
 265 
 
 4780-7 
 
 9777 
 
 88-0 
 
 106 
 
 6804-4 
 
 9684 
 
 The difference is thus less than 1 per cent. 
 
 METHOD OF INVESTIGATION. 
 
 It was impossible for a single individual to conduct so extensive an 
 investigation as that contemplated, and I was fortunate in securing the 
 co-operation of various workers in the Research Laboratory of the Koyal 
 College of Physicians. 
 
 The following scheme shows the general plan of the investigation and 
 the manner in which it was apportioned among the various workers : 
 
 How far may the Salmon examined be considered typical of their 
 respective classes ? By Walter E. Archer, Inspector of Salmon 
 Fisheries. 
 
 The Source fn m which Salmon obtain nourishment and the Exchange of 
 Material in their Body during their sojourn in Fresh Water?- 
 
 A. The Power of the Alimentary Canal to Digest and Absorb Food 
 
 1. Changes in the structure of the lining membrane of the 
 alimentary canal and in the various glands. By G. Lovell 
 Gulland.
 
 8 Investigations on the Life- History 
 
 Changes in the digestive activity of the various secretions of 
 the alimentary canal. By A. Lockhart Gillespie. 
 
 Bacteriology of the alimentary canal in different conditions. 
 By A. Lockhart Gillespie. 
 
 B. Changes in the Weight and in the Condition ofttw Muscles, Genitalia, 
 and other Organs during the sojourn of the Salmon in Fresh 
 Water 
 
 Changes in the weight and condition of the fish at different 
 periods. By D. Noel Paton and J. C. Dunlop. 
 
 Changes in the amount of solids. By D. Noel Paton. 
 
 Changes in the amount of Fats 
 
 (a) Chemical observations. By D. Noel Paton. 
 
 (&) Microscopic observations. By S. C. Mahalanobis. 
 
 The nature of the Proteids of the Muscle. By F. D. Boyd. 
 
 Changes in the amount of Proteids. By J. C. Dunlop. 
 
 The Fats and Proteids stored in the Muscle as the Source of 
 Muscle Energy. By D. Noel Paton. 
 
 The Phosphorus Compounds and the Changes in the distribu- 
 tion of Phosphorus. By D. Noel Paton. 
 
 Changes in the distribution of Iron. By E. D. W. Greig. 
 
 The Pigments of the Salmon and their Changes. By M. I. 
 Newbigin. 
 
 The Changes in the Value of the Salmon as a Food-Stuff. 
 By J. C. Dunlop.
 
 of the Salmon in fresh Water. 
 
 2. HOW FAR MAY THE SALMON EXAMINED BE CON- 
 SIDERED TYPICAL OF THEIR RESPECTIVE 
 
 CLASSES? 
 
 BY WALTER E. ARCHER, 
 
 INSPECTOR OF SALMON FISHERIES FOR SCOTLAND. 
 
 The object of these observations is to determine how far the fish 
 examined in the course of this investigation may be taken to fairly 
 represent fish frequenting each locality in the periods named. 
 
 The lower- water fish are represented by 34 females and 8 males, and 
 upper- water fish by 2 1 females and 6 males. The lower-water fish were 
 in each case taken at the mouths of the rivers. The fish from the upper 
 waters of the Spey were taken at a distance of about 60 miles from the 
 sea, those from the upper waters of the Dee at about 65 miles, and 
 those from the upper waters of the Helrnsdale at about 15 miles. Fish 
 from 8 to 10 Ibs. in weight were asked for, but those sent from the 
 mouths in October and November were considerably larger. It has 
 been shown that the average weight, per fish of standard length, of 
 salmon measuring from 69 to 89 centimetres does not vary one per 
 cent. provided the averages are calculated over large numbers, and the 
 fish are taken in the same locality and during the same period of the 
 year (Table II., p. 7). It is well known, however, that there is a 
 considerable variation in the weight of single fish of the same length, 
 taken at the same time and place. Table II., p. 65, shows the extent 
 of these variations ; and the question arises as to whether the averages 
 given in this table are taken over sufficient numbers, and therefore 
 fairly represent the average condition of fish iiieach period and locality; 
 or whether the fluctuations are due to the ordinary variations in the 
 weight of fish of the same length. 
 
 With the view of throwing further light on this question, the 
 average weight, per fish of standard length, has been calculated on large 
 numbers of fish taken in different localities in each period. The cal- 
 culations which are given in Table I. refer to female salmon taken 
 on the sea coast or immediately after entering the river. It is 
 true that Kelso, in the neighbourhood of which one lot of fish was 
 caught, is some 16 or 17 miles above the tideway ; but it would seem a 
 fair inference that these fish have entered the river in the period in 
 which they were caught, and that they should be treated as mouth and 
 not as upper-water fish, since they are altogether of a larger class than 
 those taken at Berwick-on-Tweed in July ; and, since, they resemble 
 in size the large mouth fish examined by Dr. Noel Paton in October and 
 November, being in marked contrast to the samples obtained by him 
 from the upper waters in these months.
 
 10 Investigations on the Life-ffisfory 
 
 TABLE I. 
 WKIGHT PER FISH OF STANDARD LENGTH FEMALE SALMON. 
 
 PERIOD. 
 
 LOCALITY. 
 
 Average 
 Weight. 
 
 Average 
 Length. 
 
 No. of 
 Fish. 
 
 Average 
 Weight per 
 Fish of 
 Standard 
 Length. 
 
 
 
 GRMS. 
 
 CM. 
 
 
 GRMS. 
 
 May and June, 
 
 Bervvick-on-Tweed, 
 
 4300 
 6509 
 
 73-8 
 
 232 
 
 10723 
 
 July and Aug,, 
 
 Berwick-on-Tweed, . - 
 
 82-9 
 
 221 
 
 11723 
 
 Do., 
 
 Dysart and Buckhaven 
 (Fifeshire Coast), 
 
 5942 
 
 80-2 
 
 20 
 
 11511 
 
 Do., 
 
 Tayport, 
 
 6531 
 
 82-6 
 
 40 
 
 11410 
 
 Do., 
 
 N. Esk District (Sea 
 Coast), 
 
 7166 
 
 84-6 
 
 65 
 
 11836 
 
 Oct. and Nov., 
 
 Kelso, on Tweed, - 
 
 7711 
 
 87-76 
 
 85 
 
 11408 
 
 Do., 
 
 Fochabers, on Spey,* - 
 
 8164 
 
 89 
 
 04 
 
 11580 
 
 The figures given in the last column show : 
 
 1. That the difference in the average weight, per fish of standard 
 length, in July and August on five different parts of the coast does not 
 exceed 4 per cent. 
 
 2. That in October and November the variation in the average 
 weight, per fish of standard length, from the lower waters of the Tweed 
 and Spey respectively is less than ] | per cent. 
 
 The large number of fish dealt with, the wide area over which they 
 were taken, and the very slight variation in the results, seem collectively 
 to afford good grounds for believing that these figures represent with a 
 considerable degree of accuracy the condition of female salmon coming in 
 from the sea in each of the periods specified. 
 
 A comparison of these averages with those of the estuary fish examined 
 by Dr. Noel Baton (which are given in Table IV., p. 66), shows that 
 the average weight per fish of standard length of the latter is in 
 May and June 5-3 per cent, below the former, in July and August 7'3 
 per cent, below, and in October and November not quite 1 per cent. 
 above. The smallness of the differences in these percentages would seem 
 to indicate that the fish examined by Dr. Noel Paton may be token as 
 tair samples of fish coming in from the sea in the periods named, and, in 
 any case, that the excess of weight, per fish of standard length, of the 
 mouth fish as compared with the upper-water fish is not due to his 
 samples of the former being fish in exceptionally good condition. 
 
 A similar calculation has been made with "regard to males, and is 
 given in the following table : 
 
 n pro^rliontoTheir T^ "'Th ^^^ T* nleasured whe dive. Their weight, therefore, 
 "terbe^tkine^l S Fgrea ' rt a " that f fish which were weighwl a fewboun
 
 of the Salmon in Fresh Water. 
 
 TABLE II. 
 AVERAGE WEIGHT PER FISH OF STANDARD LENGTH MALE SALMON. 
 
 11 
 
 PERIOD. 
 
 LOCALITY. 
 
 Average 
 Weight. 
 
 GRMS. 
 
 Average 
 Length. 
 
 Num- 
 ber. 
 
 Weight 
 per Fish 
 of 
 Standard 
 Length. 
 
 
 
 CM. 
 
 
 GRMS. 
 
 May and June, 
 
 Berwick-on-Tweed, 
 
 4784-8 
 
 76-11 
 
 43 
 
 10771 
 
 July and Aug., 
 
 Berwick-on-Tweed, 
 
 7275-5 
 
 86-1 
 
 123 
 
 .11400 
 
 Do., 
 
 Dysart, Buckhaven, } 
 Tayport, and N. V 
 Esk Districts, - - j 
 
 9071-8 
 
 91-9 
 
 22 
 
 11700 
 
 Oct. and Nov., 
 
 Kelso, on Tweed, - 
 
 6518-1 
 
 83-4 
 
 98 
 
 11224 
 
 Do., 
 
 Fochabers, on Spey,* 
 
 10750 
 
 98-5 
 
 21 
 
 11248 
 
 A study of this table shows : 
 
 1. That in July and August there is a difference of only 2| per cent, 
 in the weight, per fish of standard length, of salmon taken at Berwick, 
 and of those taken at Dysart, Buckhaven, &c. 
 
 2. That in October and November there is practically no difference in 
 the weight, per fish of standard length, of salmon from the Spey and 
 Tweed respectively. 
 
 A comparison of the figures given in the above table with those given 
 in Table XIV., p. 71, shows that the average weight per fish of standard 
 length taken at the mouths of rivers, which were examined by Dr. Noel 
 Paton, was in May and June 18 per cent, below that of the Berwick fish, 
 in J uly and August 7 per cent, below the mean of the averages of the fish 
 taken from the different localities, and in October and November 14- per 
 cent, below the mean of Tweed and Spey salmon. The male fish 
 examined by Dr. Noel Paton are thus not so typical of their class as are 
 the female fish. 
 
 Lastly, if the figures in the above table be compared with those given 
 in Table I., it will be seen that, as regards the weight, per fish of 
 standard length, there is a most striking similarity in males and females 
 coming in from the sea. In May and June it is practically the same ; in 
 July and August the excess in the weight of females over males is 
 under 1 per cent. ; and in October and November it is barely over 2 per 
 cent. 
 
 Material, unfortunately, is wanting to enable the same test to be 
 applied to the samples of the upper- water fish. 
 
 * The fish takrn at Fochabers were weighed when alive. Their weight, therefore, in j roportion 
 to their length, is rather greater than that of fish from other localities which were weighed a few 
 hours after being killed.
 
 Investigations on the Life- History 
 
 II. THE SOUECE FEOM WHICH SALMON OBTAIN 
 NOUEISHMENT AND THE EXCHANGE OF 
 MATEEIAL IN THE BODY DUEING THEER 
 SOJOUEN IN FEESH WATEE. 
 
 A. THE POWER OF THE ALIMENTARY CANAL TO 
 DIGEST AND ABSORB FOOD. 
 
 In regard to this question the following evidence is at present forth- 
 coming. Miescher Ruesch states (loc. cit.) that the stomach and gullet 
 of the fish taken at Basel, about 500 miles up the Rhine, were contracted 
 and folded, contrasting strongly with the distended stomach and gullet 
 of the salmon taken in the East and North Sea. The stomach and 
 intestine contain a clear slimy material which is never acid, while the 
 intestine and pyloric appendages contain a slimy pus-like material full 
 of shed epithelial cells. There was never any trace of auto-digestion. 
 The glycerin extract of the slimy matter on the addition of dilute 
 hydrochloric acid had sometimes a slightly dissolving action on fibrin, 
 but so slight that it was concluded that no true digestive secretion was 
 secreted. The gall bladder in all cases was collapsed, but the contents 
 of the intestine are described as having a more or less deeply bile- 
 coloured appearance. 
 
 He further states that the intestines of these fish taken from the river 
 did not show the same tendency to early putrefaction as did the intestines 
 of sea salmon, and this, he thinks, was due to the fact that no food being 
 taken no organisms were introduced into the stomach. In his whole 
 series of nearly 2000 fish, he found evidences of feeding in the stomachs 
 of two only, both male kelts. In one the scales of some Cyprinoid fish 
 were found, in the other an acid secretion was contained in a distended 
 stomach, possibly indicating that digestion had been going on. 
 
 From this evidence he concludes (p. 164) that "the Rhine salmon 
 from its ascent from the sea to its spawning, and also after this, as a 
 rule takes no nourishment." 
 
 The investigation of the Scottish Fishery Board carried on at Berwick- 
 on-Tweed yielded results which are hardly comparable with those of 
 Miescher, inasmuch as the fish were here captured either while still in 
 the sea or just after leaving it. 
 
 The question is not only one of very great interest, but it is of 
 prime importance as regards the further investigation of the changes 
 in muscles, ovaries, and testes. 
 
 On considering Miescher's results it seemed to us desirable to repeat 
 some of his observations and to extend the scope of the enquiry. 
 With this purpose Dr. Gulland has studied the microscopic changes in 
 the digestive tract, while Dr. Gillespie has investigated the digestive 
 activity and the bacteriology of the stomach and intestine.
 
 of the Salmon in Fresh Water. 
 
 3. THE MINUTE STRUCTURE OF THE DIGESTIVE 
 TRACT OF THE SALMON, AND THE CHANGES 
 WHICH OCCUR IN IT IN FRESH WATER. 
 
 BY G. LOYELL GULLAND, M.A., B.Sc., M.D., F.R.C.P.E. 
 
 The digestive tract of the salmon has not hitherto been the subject 
 of any very detailed examination. Its general arrangement, of course, 
 conforms to that usual in the group of Teleosteans to which it belongs, 
 and it may here be divided into stomach, pyloric appendages, intestine, 
 pancreas, and liver. All of these were examined in the series of fish 
 under consideration. 
 
 METHOD. 
 
 The same method of preparation was used in all cases in order that 
 the results might not be affected by any deviation in this respect. As 
 early as possible small portions of the organs above mentioned were 
 removed from the fish and were placed immediately in a saturated 
 watery solution of corrosive sublimate. After 24 hours they were 
 rapidly washed in water and then passed through a series of alcohols 
 increasing in strength. They were embedded in paraffin, cut with the 
 rocking microtome, and fixed to the slide by my water method. One 
 set of sections was always stained with heematoxylin and eosin, whilst 
 other stains, especially the usual anilin dyes, were employed for com- 
 parison. The sections were all mounted in balsam. 
 
 LITERATURE. 
 
 The digestive tract of the salmon has never been examined micro- 
 scopically with special care in recent tunes, but the stomach of the nearly 
 allied trout has been described by Valatour (1), Cajetan (2), and 
 Oppel (3). 
 
 The most important contribution to the subject hitherto has been 
 that by Miescher (4), who found that the stomach and gullet of the fish 
 taken at Basel, far up the Rhine, were contracted and folded, contrasting
 
 14 Investigations on the Life-History 
 
 strongly with the distended stomach and gullet of the salmon taken in 
 the Baltic and North Sea. His results are described on p. 165 et seq, 
 
 It seemed desirable to re-examine the subject, and especially to 
 subject the digestive tract of the salmon under various conditions to 
 minute histological investigation. 
 
 THE STOMACH OF SALMON ENTERING THE RIVER. 
 
 The organ is surrounded by a serous coat, while beneath this are two 
 layers of non-striped muscle. The external layer is thin and is disposed 
 longitudinally ; the internal layer is circular and five or six times as 
 thick as the outer one. Between the two layers run blood vessels, 
 lymphatics, and a nerve plexus, with an unusually large number of nerve 
 cells, often grouped together into comparatively large ganglia. Beneath 
 the muscular layers lies the submucosa, with many large blood vessels. 
 The muscularis mucosse consists of two layers, an external longi- 
 tudinal and more delicate, and an internal circular rather thicker layer. 
 The mucosa may be divided into two parts, the glandular portion and the 
 connective tissue portion which underlies the glands and which supports 
 them. The mass of connective tissue underlying the glands is very 
 considerable, being often nearly as thick as the glandular layer-, and is 
 itself divided into two layers by the remarkable structure described by 
 Oppel in the stomach of the trout, the " membrana compacta " or 
 " stratum coinpactum." This layer, in whatever plane the stomach is 
 cut, is always found as a compact hyaline band lying rather nearer the 
 muscularis rnucosre than it does to the fundi of the glands. It is, of 
 course, pierced by the blood vessels, etc., but I have never seen muscle 
 strands from the mu<cularis mucosse passing through it. It contains no 
 nuclei, and no structure can be made out in it by ordinary methods. 
 Nuclei lie upon it, however, and the fibres of the connective tissue on 
 either side are directly continuous with it (Fig. 10), and behave to all 
 reagents in the same way as it does. It is, therefore, certainly of con- 
 nective tissue origin, and is as certainly not elastic tissue. The fibrous 
 tissue outside this layer is more delicate than that inside it, and the 
 inner layer contains more blood vessels, especially large venous spaces, 
 than the outer one. A special feature of both layers is the great 
 number of large eosinophile leucocytes to be found in "the meshes of the 
 connective tissue ; in fact, nil the many leucocytes present here seem to 
 be of this variety (Fig. 10). 
 
 In the epithelial lining of the mucous membrane the cells are of three 
 types : 
 
 1. The superficial epithelium and that forming the ducts of the 
 
 glands. 
 
 2. The intermediate epithelium of the glands. 
 
 3. The zymin-forming epithelium of the glands. 
 
 1. The superficial epithelium (Fig. 8) is precisely like that found 
 in most fish stomachs long cylindrical or columnar cells with oval nuclei 
 about the middle of the cell. Where they are best developed, on the 
 projections between the mouths of the glands, they have a narrow clear 
 hem on the surface, and below that a portion of the cell, which looks 
 more hyaline and stains rather more deeply than the rest, and is sharply 
 marked off from the deeper portion, which shows an ordinary proto- 
 plasmic structure. These cells are not goblet-cells, and no such cells 
 are found in the stomach. The glands are very thickly set over the 
 stomach and open by wide ducts, down which the superficial epithelium 
 extends unaltered for some distance, usually down to the point where 
 the glands begin to branch. Oppel notes that this branching or opening
 
 the Salmon in Fresh Water. 15 
 
 of several secreting tubes into a common duct occurs very frequently in 
 the trout, and I think that in the salmon it is still more frequent. 
 
 2. Before the branching, of the glands begins, the characteristic upper 
 end (Oppel's, Oberende) of the cdl becomes less distinct and soon ceases 
 to be evident, and the whole of tlie cell body becomes granular and 
 undifferentiated. This I call the intermediate epithelium (Fig. 9). In 
 the glands of the cardiac or anterior part of the stomach this part of 
 the gland is very short, but in the pyloric region it occupies a large 
 part of the gland. 
 
 3. The zyrnin-secreting epithelial cells do not exhibit any transi- 
 tion from the intermediate ones, but are sharply distinguished from 
 them (Fig. 9). They are cubical, have a large rounded nucleus poor 
 in chromatin, and a cell body with a very evident spongioplasm. The 
 .surface next the lumen of the gland is not differentiated in any way. 
 In the cell body are scattered numerous granules which stain with 
 eosin, though not very strongly, and which can be brought out best by 
 M. Heidenliain's iron-hsematoxylin, with which they stain an intense 
 black. I have 110 doubt, from the analogy of the granules in the 
 pancreas, that these are zymogen granules. They vary slightly in size, 
 and are always most numerous towards the free end of the cell. Their 
 actual number, or at least the ease with which they can be demon- 
 strated, varies very much in different stomachs, and even in different 
 parts of the same stomach, and probably would be found to depend upon 
 whether the organ had been recently called on to digest at the time of 
 death or not. 
 
 The amount of this variety of epithelium present in the glands varies 
 greatly with the part of the stomach examined. About one-half or 
 one-third of the vertical extent of the cardiac glands is occupied by this 
 epithelium (Figs. 1, 4, 7), while at the pylorus there may be only a few 
 cells of this sort at the bottom of a tube formed in about equal propor- 
 tions of the superficial and intermediate epithelia. Perhaps one-twelfth 
 or less of the whole extent in the pyloric glands is occupied by this 
 epithelium. The glands intermediate in position between these two 
 regions are intermediate ako in this respect. 
 
 The above description of the normal stomach is drawn up from 
 examination of the stomachs of seven fish caught at Berwick in March 
 1896. Portions of their stomachs were fixed in sublimate solution as 
 soon as the fish were killed. 
 
 STOMACHS OF SALMON FROM UPPEK WATERS OF RIVERS. 
 
 The stomachs of fish killed in the upper reaches of rivers present 
 very striking differences from the normal type, and these seem to be caused 
 by a desquamative catarrh of the mucous membrane. The muscular 
 and submucous layers show no change, the muscularis mucosse is 
 unaltered, but the connective tissue of the mucous membrane looks 
 swollen and hyaline. This appearance is best seen in the stratum 
 compactum, which is thicker than in the normal stomach, and often 
 much more folded, as though its total volume were increased. The 
 number of eosinophile leucocytes in the meshes of the connective tissue 
 is also usually increased. But the principal change is in the epithelium of 
 the glands. In the extreme cases this is almost entirely desquamated, 
 even from the fundi (Figs. 2 and 3); but usually more or less of the 
 zymin-secreting epithelium is preserved in situ, though in a degenerated 
 state. The superficial and intermediate epithelia are the first to dis- 
 appear, and usually cannot be recognised at all. The fundal epithelium 
 is never normal. The protoplasm of the cells loses its granular appear-
 
 Hi Investigations on the Life- History 
 
 auce and stains deeply and nearly uniformly with eosin, while in the 
 nucleus the chromatin becomes massed together into a single small 
 shrivelled deeply-staining ball, or breaks up into several smaller balls 
 of that character. It never remains unaltered. The cells presenting 
 these characters may either remain attached to the basement membrane 
 of the glands or may lie in detached masses in the lumen of the glands 
 (Fig. 2). Very often, too, leucocytes wander out from the connective 
 tissue beneath into the glands and lie among the degenerated epithelial 
 cells ; these are generally of the eosinophile variety, but the granules 
 seem soon to lose their distinctive reaction, and the leucocytes can then 
 with difficulty be distinguished from the degenerated epithelial cells. 
 
 Sometimes this mixed mass of cells lies on the surface of the mucous 
 membrane and presents an appearance very much like that to be 
 described in the intestine and pyloric appendages (p. 18). This material 
 probably represents the slimy substance mentioned by Miescher. 
 
 The connective tissue septa lying between the glands fall together, and 
 iu extreme cases the appearance presented is more like that of granu- 
 lation tissue from an ulcerated surface than a mucous membrane. 
 
 Now, it is of course well known that in the stomachs of the higher 
 animals post-mortem changes, and notably post-mortem digestion, take 
 place often with great rapidity, and it was obviously of great importance 
 to make sure that the appearances just described were not due to some 
 such process, especially as the stomachs of the salmon from the higher 
 river reaches could not arrive in Edinburgh in less than several hours. 
 In order to resolve this difficulty, Dr Noel Paton, during the course of ;i 
 fishing excursion, preserved a number of trout stomachs and other parts 
 of the alimentary tract, exactly as had been done with the salmon, some 
 absolutely fresh, others at intervals after death of ten minutes, one hour, 
 two hours, three hours, and six hours. These were all cut and examined, 
 and though I shall have to say more about the pyloric appendages and 
 intestines of these fish, it is not necessary to describe the stomachs in 
 detail, as it was found that even six hours after death there was practically 
 no post-mortem change. It would not have been possible to have dis- 
 tinguished these stomachs from those preserved at once. Even the. 
 superficial epithelium was completely preserved, and the cells of the 
 deeper parts of the glands gave excellent demonstrations of zymogen 
 granules when treated with iron-hsematoxylin, while their nuclei and 
 protoplasm remained unaltered. The connective tissue never showed 
 the hyaline change. All these trout stomachs contained food, generally 
 the remains of small crustaceans or insects, which they were actively 
 digesting, and were therefore precisely in the condition where one 
 would have expected post-mortem digestion to be specially rapid. The 
 salmon stomachs I have described as showing this " catarrhal " change 
 did not contain food and were therefore not active, and it seems there- 
 fore reasonable to conclude that the catarrhal change was not due to 
 this cause. The stomach of the trout may quite fairly be compared 
 with that of the salmon, as it is merely a miniature copy of it. The 
 main points of difference between the two are that in the trout the 
 glands are shorter, the stratum compactum is very much thinner, the 
 connective tissue less in amount, and the muscular coats, of course, not 
 so strongly developed. The minute structure of the different elements 
 of the organ is precisely similar in the two fish. 
 
 Moreover, in some stomachs from the salmon, notably in that from 
 No. 72, which was caught at sea, we had an opportunity of seeing the 
 change which really takes place post-mortem, as this salmon had been 
 out of the water 36 hours or more before it reached us. In this case 
 the connective tissue has the usual appearance, without the hyaline
 
 of the Salmon in Fresh Water, 17 
 
 change, the zymin-secreting cells are well preserved and show no 
 chvomatolysis of their nuclei, and it is only the superficial epithelium 
 which is altered. In these cells the nuclei are shrunken, the cell- 
 bodies are swollen and agglutinated, so that their outline has become 
 less distinct, and they look much like the cells of mucous glands after 
 treatment with water. But the cells retain their arrangement, and are 
 not cast off as in the fish from the rivers. 
 
 STOMACHS OF KELTS. 
 
 It was exceedingly interesting to find that these had regained the 
 normal appearance. The fish did not reach the laboratory till many 
 hours after death, so that there was a certain amount of the post- 
 mortem change in the superficial epithelium noted above. The zyrnin- 
 secreting epithelium, however, and the rest of the mucous membrane 
 were quite normal in every way (Fig. 4). 
 
 THE PYLORIC APPENDAGES AND INTESTINE. 
 
 The appendages in the salmon are very numerous, and some doubt 
 has always prevailed as to their real significance, whether they are to 
 be regarded as secreting or absorbing organs. I think there can be no 
 doubt that, in the Salmonidre at all events, they fulfil the latter 
 function, for in structure they exactly resemble the upper part of the 
 intestine, so much so in fact that but for the difference in size it would 
 be impossible to say whether a section came from one or the other. 
 The digestive action which their contents have been shown, in another 
 part of this research, to possess, (p. 34) is probably due to the secretion 
 of the pancreas. The ducts of this organ appear to open into the appen- 
 dages, and its secretion would naturally impart to the contents a digestive 
 action. 
 
 The intestine and appendages both have a peritoneal investment, an 
 external longitudinal and internal circular and thicker muscular coat, 
 no muscularis mucosa?, a well-marked stratum compactum. exactly the 
 same in character as that found in the stomach, a mucous membrane 
 thrown into longitudinal folds, and covered by a cylindrical epithelium 
 with the usual striated hem, and containing numerous chalice cells (Figs. 
 5, 11, 12). The only difference between the two organs is that, generally 
 speaking, the folds in the intestine are set more closely together, so that 
 the deepest parts of the folds look in sections like short tubular glands or 
 Lieberkiihiiian follicles, whilst in the pyloric appendages the folds are 
 more open and there is no likelihood of imagining the existence of 
 glands at their bases. In both structures the eosinophile leucocytes are 
 numerous, but are to be found mainly in the connective tissue about the 
 stratum compactum. The leucocytes in the folds and passing through 
 the epithelium are usually either of the hyaline or the smaller oxyphile 
 variety. The epithelial cells retain their striated hem (or fringe of 
 processes, as it probably really is), right down to the bottom of the 
 folds. 
 
 On opening either of these structures in the fresh state there is 
 always in the lumen a semi-fluid pultaceous mass varying in consistence 
 between jelly and pus, and more or less yellow in colour. This is 
 the case alike in the salmon from the river mouth, from the upper 
 reaches, and from the sea. In the lower gut in this material are 
 numerous more opaque hard masses. These are composed of large 
 crystals of carbonate of lime held together by mucus. In none of the 
 very many specimens examined was the smallest trace of undigested
 
 18 Investigations on the Life-History 
 
 .food found in the intestinal tract. In the intestine of the trout 
 examined the remains of food were constantly present, and appeared to 
 consist mainly of parts of the exoskeleton and appendages of small 
 insects and crustaceans. In one case similar material was found in the 
 pyloric appendages, in other cases these were either empty or merely 
 contained eiitozoa. 
 
 On microscopic examination of the appendages and intestine of the 
 salmon it is found that the pus-like material is due to a des- 
 quamative catarrh exactly like that found in the stomach (Fig. 6). 
 The mass in the tube is made up mainly of rounded cells staining 
 deeply with eosin, and having their nucleus rounded, somewhat varying 
 in size, but always staining deeply and uniformly with haematoxylin. 
 No chromatin network can be made out. In addition a few leucocytes 
 may be present and one or two shrunken goblet cells. The main mass 
 of cells is certainly derived from the degeneration of the columnar 
 epithelium, which in these cases is shed almost entirely from the folds 
 of the mucous membrane. It is almost always easy to find some spot 
 between the folds where this epithelium remains unaltered, and within 
 quite a short distance one can trace every stage of degeneration until 
 the same form as that lying free in the lumen is reached. Fig. 13 
 will make this clearer than any description. 
 
 Sometimes the debris in the tube is more granular and the cellular 
 structure less easily made out, but that is evidently merely a later 
 stage of the same process. 
 
 I have never found a salmon in the intestine and pyloric appen- 
 dages of which (for the two are always at the same stage of the process, 
 another proof of their identity of function) this change was not present 
 to a greater or less extent. The pyloric appendages and intestine of 
 the seven Berwick salmon were examined, and as these had all been 
 fixed immediately after death with sublimate, there could be no 
 question of post-mortem change. In four out of the seven the change 
 was practically complete, either the entire epithelium was degenerated, 
 or only a little was left deep down between the folds. In the remaining 
 three the change, though present, was less marked, being confined 
 mainly to the apices of the folds; in one there was very little catarrhal 
 change. In all the fish from the higher reaches, from the sea, and in 
 the kelts from the river the change was complete. It is very curious 
 to see the connective tissue framework of the folds, with its blood 
 vessels much congested as a rule, lying absolutely bare of epithelium in 
 this pus-like mass (Fig. 6). 
 
 This change must certainly be a pathological, catarrhal, or seasonal 
 one, for in the trout we see nothing of it. There the columnar 
 epithelium everywhere covers the folds, both in the specimens fixed 
 immediately after death, and in those fixed at varying times post- 
 mortem, except in the intestine of the specimen fixed six hours after 
 death. Here there is indeed a considerable desquamation of 
 epithelium, which is lying free in the lumen of the gut, but the cells 
 are not degenerated in any way. They still exhibit the characteristic 
 hem, their nuclei show the chromatin network, and the desquamation is 
 probably accidental, and due to some squeezing of the specimen before 
 it was fixed. 
 
 There is one source of fallacy in these cases, or rather what might be 
 regarded as a source of fallacy, that is the presence of parasitic worms 
 in the intestine and pyloric appendages of the salmon. There are few 
 fish which are entirely free from these, and sometimes the intestine is 
 greatly distended with them. It might be thought that these were the 
 cause of the catarrh, and indeed one finds on section that in some of
 
 of the Salmon in fresh Water. 19 
 
 the intestines which contain thern there is nothing left but the muscular 
 coats, and a mere shred of connective tissue infiltrated with leucocytes. 
 But they are almost as common in the trout as in the salmon, and there 
 their presence does not produce a desquamative catarrh, but simply a 
 flattening out of the folds of the mucous membrane from distension ; the 
 epithelium remains intact. It is noticeable, however, that when these 
 worms are present in the trout the number of goblet-cells in the epithelium 
 is always unusually large, sometimes, indeed, the goblet-cells considerably 
 exceed the ordinary epithelial cells in number, as if the irritation caused 
 by the presence of the worm necessitated a greater flow of mucus to 
 lubricate the surface of the mucous membrane. 
 
 THE PANCREAS. 
 
 This is not gathered into a compact organ, but the acini are scattered 
 more or less diffusely through the long strands of intraperitoneal fat 
 lying round the stomach, pyloric appendages, and intestine (Fig. 14). The 
 microscopic ducts one can hardly call them interlobular or intralobular, 
 as there are no true lobules are lined with a cylindrical epithelium, and 
 resemble the ducts of mammalian salivary glands much more than those 
 of the mammalian pancreas. The cells of the secreting acini are like 
 pancreas-cells elsewhere, and they evidently go through exactly the same 
 cycle of appearance during the formation of and extrusion of zymogeii 
 granules as those described by Langley. One point of difference there is, 
 however, inasmuch as in the trout and salmon the zymogen granules in the 
 pancreas, as in the stomach cells, stain a deep black with iron-h?emat- 
 oxylin, which renders it very easy to make out the stage of secretion. 
 Fig. 1 5 shows a pancreatic acinus where the cells are full of granules, the 
 so-called stage of " rest," when no extrusion of granules is going on, 
 but where they are being heaped up in the cell ready to aid the process 
 of digestion. Fig. 16 depicts an acinus where the granules have mostly 
 been extruded, the so-called " active " stage. The only pancreas where 
 I found the cells completely full of granules was that of a trout which 
 had been preserved immediately after death. All the other trout and 
 all the Berwick salmon showed the cells more or less emptied of granules. 
 The pancreas was not often present hi the portions of salmon from the 
 rivers fixed for examination, but where it was to be seen the cells were 
 generally shrunken and shrivelled, and contained no granules. 
 
 THE LIVEK. 
 
 Comparatively few livers were examined, and these showed no very 
 marked difference beyond the presence or absence of fat. This is brought 
 out better, however, by chemical analysis (p. 100) and need 
 not here be discussed. Generally speaking, however, it was found 
 that the livers of the salmon taken at the river mouths contained much 
 fat (Fig. 18), while those of the salmon from the upper reaches, and the 
 kelts, were deficient in it (Fig. 1 7). The fat, where present, was generally 
 in the formof large droplets in the cells, and was distributed pretty 
 equally throughovit the organ. 
 
 THE GALL BLADDER. 
 
 The following are the statistics with regard to the state of the gall 
 bladder :
 
 20 
 
 Investigations on the Life- History 
 (a) Fish at the Mouth of the River ; 
 
 or, in Percentage of Fish Taken. 
 
 
 uisienueu. 
 
 
 May 
 
 9 
 
 3 
 
 June - 
 
 4 
 
 
 
 July - 
 
 10 
 
 2 
 
 August 
 
 3 
 
 2 
 
 October 
 
 
 4 
 
 November 
 
 
 
 7 
 
 Distended. 
 
 Empty. 
 
 May - 
 
 June - 
 
 75 
 100 
 
 25 
 
 
 
 July - 
 
 83 
 
 
 August 
 
 60 
 
 40 
 
 October 
 
 33 
 
 67 
 
 November - 
 
 
 
 100 
 
 (fe) 7''is/i in Upper Waters. 
 In all the gall bladders were collapsed. 
 
 (c) Kelts. 
 
 In most of these the gall bladders were distended. 
 
 I examined several gall bladders microscopically, and they all, whether 
 distended or empty, whether from fish at the mouth of the river, in the 
 upper waters, or from kelts, showed a desquamative catarrh of exactly 
 the same kind as that described in the stomach, intestine, etc. In some 
 the epithelium had entirely disappeared, while in others part of it could 
 be seen in a degenerated state, either lying detached in the lumen of the 
 bladder, as was more usual, or attached in fragments to the wall. There 
 is no stratum compactum in the gall bladder ; the connective tissue was 
 in a state of more or less evident hyaline degeneration. 
 
 CONCLUSIONS. 
 
 We may take it for granted that at some period of its existence the 
 salmon's alimentary tract has the same normal structure as that of the 
 trout, and it is evident that its sojourn in the sea is the time of normal 
 digestive activity. Probably for some time before the fish enter the 
 river, and certainly while they are lying at the mouth of it, the catarrhal 
 change begins, and begins clearly in the intestine and pyloric append- 
 ages ; the stomach is at that time unaffected. By the time the fish have 
 reached the upper waters the stomach has been attacked, and the 
 whole digestive tract is in a state of catarrh. After spawning is over, 
 the stomach is the first part to recover, and in the kelts it is again histo- 
 logically normal, while the intestine and pyloric appendages probably 
 recover when the fish have returned to the sea.
 
 of the Salmon in Fresk ll'ater. 
 
 21 
 
 It is evident that this desquamative catarrh is not caused by the 
 action of fresh water either on the general health of the fish or locally 
 on the parts of the alimentary canal, for in many fish taken from the 
 sea the change was already complete in the intestine and appendages. 
 
 Finally, it is well again to emphasise the fact that in no part of the 
 alimentary canal of the many fish examined, including kelts, were any 
 remains of undigested food discovered upon microscopic examination. 
 
 LITERATURE. 
 
 1 . Valatonr M. Recherches sur les glandes gastriques et les tuniques 
 musculaires du tube digestif dans les Poissons osseux et les Batraciens. 
 Ann. des Sc. nat. 4. Ser. Zool. T. 16. 1861. 
 
 2. Cajetan, J. Ein Beitrag zur Lehre von der Anatomie und 
 Physiologie des Tractus intestinalis der Fische. Inaug.-Diss. Bonn. 
 1883. 
 
 3. Oppel, A. Lehrbuch der vergleichenden mikroskopischen Anatomie. 
 ler. Teil. Der Magen. Jena.. 1896. 
 
 4. Jliescher. Fischerei-Ausstellung zu Berlin. 1880. 
 
 DESCRIPTION OF THE FIGURES. 
 
 The following letters are used to indicate the same structures through- 
 out : 
 
 eosiiioplule leucocyte, 
 mucosa. 
 submucosa. 
 
 epithelial part of mucous 
 me. 
 
 superficial epithelium, 
 int. ep. , - intermediate epithelium, 
 zymin-secreting epithelium, 
 zymogen granules, 
 columnar epithelium, 
 chalice cell. 
 
 degenerated epithelium, 
 pancreatic duct. 
 - fat. 
 
 Figs. 1 to 6 are micro-photographs of actual sections ; the lens used 
 was Leitz 3 and ocular 4. The remaining Figures are drawings by the 
 author. The outlines were, in all cases, filled in with Zeiss's camera 
 lucida. For Figs. 8, 9, 10, 15, 16. 17, 18, the objective was Zeiss's 
 homog. immers., apochr. 2'0 mm., apert. 1'40 with compensat. ocular 8: 
 and the magnification is therefore x 1000; for Figs. 12 and 13, the same 
 objective, with compensat. ocular 4, magnification x 500 ; for Fig. 7, 
 Zeiss DD., with ocular 2, magnification about x 200; for Figs. 11 and 
 14, Leitz 3 with ocular 4, magnification about X 60. 
 
 Fig. 1. Stomach of salmon from mouth of river (Berwick), showing 
 normal mucous membrane. Iron-ha?matoxylin. 
 
 Fig. 2. Stomach of salmon from upper waters, showing early stage of 
 degeneration and desquamation, and hyaline change in connective tissue. 
 Iron-h?ematoxylin. 
 
 Fig. 3. Stomach of salmon from upper waters, showing very advanced 
 stage of degeneration of the mucous membrane. Iron-haematoxylin. 
 
 Fig. 4. Stomach of kelt, showing regenerated mucous membrane. 
 The secreting epithelium of the glands is loaded with zyniogen granules, 
 which are stained black. Iron-hrematoxylin. 
 
 Fig. 5. T.S. Intestine of salmon from the mouth of river (the only 
 one where there was no catarrhal change), showing the folds of the 
 
 scr. , 
 
 serous coat. 
 
 eos. 1., 
 
 m. long., 
 
 longitudinal muscular coat. 
 
 muc. , 
 
 m. circ. , 
 
 circular muscular coat. 
 
 s. muc., 
 
 in.ni., 
 
 muscularis mucosa?. 
 
 ep. m., 
 
 c.t,, 
 
 connective tissue. 
 
 men 
 
 c.t.f., 
 
 connective tissue fibre. 
 
 s. ep., 
 
 c.t.n., 
 
 connective tissue nucleus. 
 
 int. ep., 
 
 s.c. , 
 
 stratum compactum. 
 
 z. ep., 
 
 b.-v., 
 art. , 
 
 blood-vessel, 
 artery. 
 
 ? g r -> 
 col. ep., 
 
 ven. 
 
 vein. 
 
 ch. c. , 
 
 cap., 
 r.b.c. , 
 1 . 
 
 - capillary, 
 red blood corpuscle. 
 
 deg. ep. 
 
 r-
 
 22 Investigations on the Life-History 
 
 mucous membrane cut across and covered with columnar epithelium. 
 Hsematoxylin and eosin. 
 
 Fig. 6. T.S. Intestine of salmon from upper waters, with catarrhal 
 change far advanced. Only a few patches of epithelium at the bottom 
 of the folds remain attached, and these are degenerated. Hseruatoxylin 
 and eosin. 
 
 Fig. 7. Stomach of salmon from mouth of river, to show normal 
 arrangement. Hsematoxylin and eosin. 
 
 Fig. 8. Superficial epithelium of stomach (estuary salmon). Irori- 
 hsematoxylin. 
 
 Fig. 9. Junction of intermediate and zymin-secreting epithelium from 
 gastric gland (estuary salmon). Iron-hsematoxylin. 
 
 Fig. 10. Stratum compactum from gastric mucous membrane (estuary 
 salmon), to show its continuity with the neighbouring connective 
 tissue-fibres, and the number of eosinophile leucocytes about it. (The 
 details of the nuclei of the leucocytes have been omitted). Hsernatoxy- 
 lin and eosin. 
 
 Fig. 11. T.S. through whole thickness of wall of pyloric appendage 
 (estuary salmon), to show arrangement and the identity of its structure 
 with that of the intestine. Hsematoxylin and eosin. 
 
 Fig. 12. Portion of a longitudinal section through a fold of intestinal 
 mucous membrane (estuary salmon). Haematoxylin and eosin. 
 
 Fig. 13. Intestine of salmon from mouth of river, showing a patch of 
 normal epithelium at the bottom of one of the folds, and the process of 
 degeneration and desquarnation which the cells are undergoing. Hsema- 
 toxylin and eosin. 
 
 Fig. 14. Pancreas (estuary salmon), showing its distribution in the 
 fat lying between the pyloric appendages. Hsematoxylin and eosin. 
 
 Fig. 15. Pancreas (trout), showing an acinus in the "resting" stage, 
 with the cells full of zymogen granules. Iron-hajmatoxylin. 
 
 Fig. 16. Pancreas (trout), showing an acinus in the "active" stage, 
 when most of the granules have been discharged. Iron-hsematoxylin. 
 
 Fig. 17. Liver (salmon), from upper water, with only a small amount 
 of fat in the cells. Hsematoxylin and eosin. 
 
 Fig. 18. Liver (salmon), from sea, the cells distended with fat 
 globules. Hasmatoxylin and eosin.
 
 PLATE I. 
 
 FIG. 
 
 ep m. 
 
 
 tii
 
 PLATE II. 
 
 m U 
 
 m.circ. 
 
 FIG. 3. 
 
 >s.ep 
 
 z.ep. 
 
 c.t.Jc. 
 
 FIG. 4.
 
 PLATE III. 
 
 ep.m. 
 
 FIG. 5. 
 
 ep.m. 
 
 FIG. 6.
 
 PLATE IV. 
 
 FIG. 7- 
 
 int.ep.- 
 
 fi 
 
 ' x 
 
 z.ep. 
 
 .eosl, 
 
 ,c.tf , c .t.n. 
 
 :i / 
 
 / /01 
 
 
 
 c.t.f. 
 
 c.tf. 
 
 FIG. 10.
 
 PLATE V. 
 
 colep. 
 
 coLep. 
 
 colep.- - 
 
 FIG. 11. 
 
 de^.ep. 
 
 ch.c 
 
 colep 
 
 FIG. 13.
 
 PLATE VI. 
 
 .z.ep. 
 
 c.t.f. 
 
 FIG. 14. 
 
 FIG. 15. 
 
 *-. 
 
 FIG. 1 6. 
 
 FIG. 17. c.t.n. 
 
 
 
 Mo. 18.
 
 of the Salmon in Fresh Water. 23 
 
 4. CHANGES IN THE DIGESTIVE ACTIVITY OF THE 
 SECRETIONS OF THE ALIMENTARY CANAL OF 
 THE SALMON IN DIFFERENT CONDITIONS. 
 
 BY A. LOCKHART GTLLESPIE, M.D., F.R.C.P.E., F.R.S.E. 
 
 1. PRELIMINARY. 
 
 As already pointed out, the question of whether salmon feed during 
 their sojourn in the river has been much debated. The absence of food 
 from the alimentary canal has been variously explained by activity of 
 digestion or by the power of rejecting the contents of the stomach when 
 the fish is captured. 
 
 Dr. Gulland's investigations have demonstrated the occurrence of a 
 degeneration of the mucous membrane of the alimentary tract during 
 the stay of the fish in the river, and very clearly indicate that little or 
 no absorption of food can go on. 
 
 In this investigation the digestive activity of the various parts of the 
 alimentary tract is considered. 
 
 The points investigated are the proteolytic and diastatic powers of 
 extracts made from the mucous membrane lining the stomach, the bowel, 
 and the pyloric appendages, and the variations in these in relation to 
 the season and the part of the river from which the fish were obtained. 
 
 It is well known that the peptic digestion of proteids in cold-blooded 
 animals owes its activity at low temperatures it can take place at C. 
 to the large proportion of pepsine present in the secretion of the 
 gastric glands. 
 
 There are two considerations concerning the degree of activity of 
 enzymes, or unformed ferments, which apply to the subject under dis- 
 cussion. The first is that the amount of digestive action exerted by any 
 agent is in direct proportion to the quantity of enzyme present, while 
 the second is that enzymes are more active in media as the temperature 
 rises from deg. to 40 degs. Cent., their power gradually diminishing 
 as the temperature rises above 40 degs., until at 70 clegs, all activity 
 ceases. 
 
 In fish the large proportion of pepsine .allows rapid proteolysis to take 
 place in the stomach, although the temperature at which it occurs may 
 be low, and if the active secretion be tested outside the body at a higher 
 temperature, a very much more powerful action is exerted on proteids 
 than by the ordinary peptic extract obtained from the gastric mucous 
 membrane of mammals. 
 
 Charles Richet, in his work entitled Du Sue Gastrlque chez I'JIonime 
 et les Animaux, proved that the gastric juice in marine fish, such as the 
 dog-fish, is almost neutral when fasting, and mucoid in character. 
 During digestion the secretion is much more acid than in man, and con- 
 tains a more active pepsin. In a dog-fish weighing 1 kilogramme he 
 obtained 5 grammes of dried gastric mucous membrane, which was 
 capable of digesting 150 grammes of egg albumin, or nearly one-sixth of 
 the total weight of the fish. In Scyllium he found the gastric acidity 
 to be as high as 0'79 per cent. HOI.
 
 24 Investigations on the Life-History 
 
 Krukenberg (Untersuchungen aus dem phys. Instit. der Univ. Heidel- 
 berg, 1882, II., p. 396) states that the pepsine of the stomach of fish, 
 or an analogous body to pepsine, acts as well at 20C. as at 40C., 
 and is most powerful in solutions of hydrochloric acid containing 1, 
 1-5, or 2 grammes per litre, but is active in solutions with 10, 15, or 
 20 grammes of this acid in the litre. 
 
 The frequent absence of the remains of food in the stomach of feed- 
 ing fish very shortly after its ingestion led some to the idea that the 
 rapidity of digestion might be accounted for by the action of the bacteria 
 in the stomach in assisting the gastric ferment, or might even be due 
 to the unassisted action of the bacteria. 
 
 Richet, however, has showed (loc. cit.) that an extract of the gastric 
 mucous membrane of fish is capable of digesting albumin in a 2'3 per 
 cent, solution of hydrochloric acid, and in the presence of ether or 
 chloroform in excess, or of cyanide of potash. Under none of these 
 conditions would bacteria be able to exist. 
 
 In herbivorous fish, such as the carp and tench, a diastatic ferment is 
 present in the gastric secretion. In carnivorous fish this ferment is 
 absent. 
 
 In 1880 Miescher Ruesch published an important paper founded 011 
 his observations on the physiology of salmon caught in the Rhine during 
 the preceding eight years. He agreed with Barfurth, His, and Glaser, 
 that " the Rhine salmon takes no food from the time when it leaves 
 the sea until it has spawned, and seldom even after this," until it again 
 reaches the salt water. No remains of food were found by him in any 
 of the winter and spring fish examined. The mucus occurring in the 
 stomach was never acid in reaction. No active digestive ferment 
 seemed to be secreted, while a glycerine extract of the gastric mucous 
 membrane exhibited little proteolytic power. 
 
 In a male fish, however, coming from the spawning beds a kelt he 
 found in a large, flabby stomach two fairly large fish whose anterior 
 portions were already digested. In another male kelt, although no 
 trace of food was present, he found that the thin secretion of the 
 stomach was of acid reaction. 
 
 To sum up the outcome of Miescher Ruesch's work, it would seem 
 that salmon ascending streams to the spawning grounds do not feed, 
 and that if they swallow portions of food they are unable to digest 
 them. After they have spawned, the males occasionally take food on 
 their way down to the sea ; the female fish may or may not do so, but 
 Miescher Ruesch failed to find any evidence in support of this, while as 
 regards the male fish, the gastric glands have become so far more active 
 that their secretion possesses an acid reaction. 
 
 2. THE MATERIAL EXAMIXED. 
 
 In Table I. the details regarding the date of capture, the part of the 
 river from which the fish were obtained, the number of fish used for 
 investigating the peptic and tryptic power of their extracts, and the 
 total number of salmon employed are arranged in tabular form : 
 
 [TABLE.
 
 of the Salmon in Fresh Water. 
 
 TABLE 1. 
 
 TABLE OF FISH EMPLOYED. 
 For Digestive Activity of Gastric Extract. 
 
 25 
 
 No. 
 
 Year. Month. 
 
 No. of Fish. 
 
 Part of River. 
 
 Kelts. 
 
 Mouth. 
 
 Upper. 
 
 1 
 
 1895. 
 
 July. 
 
 X. 
 
 
 1 
 
 
 2 
 
 
 
 XI. 
 
 1 
 
 _ 
 
 _ 
 
 3 
 
 
 
 XII. 
 
 
 _ 
 
 _ 
 
 4 
 
 
 
 XIII. 
 
 
 _ 
 
 _ 
 
 5 
 
 
 
 XIV. 
 
 
 1 
 
 1 
 
 6 
 
 . . August. 
 
 XIX. 
 
 
 _ 
 
 _ 
 
 7 
 
 ',. i September. 
 
 XXIV. 
 
 
 _ 
 
 _ 
 
 8 
 
 
 October. 
 
 XXIX. 
 
 
 _ 
 
 _ 
 
 9 
 
 
 
 XXX. 
 
 
 _ 
 
 _ 
 
 10 
 
 
 
 XXXI. 
 
 
 _ 
 
 _ 
 
 11 
 
 '| 
 
 November. 
 
 XXXVII. 
 
 
 1 
 
 _ 
 
 12 
 
 
 
 XXXVIII. 
 
 
 1 
 
 _ 
 
 13 
 
 
 Deoember. 
 
 XL. 
 
 
 _ 
 
 _ 
 
 14 
 
 1896. 
 
 March. 
 
 I. 
 
 
 _ 
 
 _ 
 
 15 
 
 * 
 
 ' 
 
 II. 
 
 
 _ 
 
 _ 
 
 16 
 
 
 
 III. 
 
 
 _ 
 
 _ 
 
 17 
 
 
 
 IV. 
 
 
 _ 
 
 _ 
 
 18 
 
 
 
 V. 
 
 
 _ 
 
 _ 
 
 19 
 
 " 
 
 
 VI. 
 
 
 _ 
 
 _ 
 
 20 
 
 " 
 
 " 
 
 VII. 
 
 
 _ 
 
 
 21 
 
 
 
 VIII. 
 
 _ 
 
 1 
 
 1 
 
 22 
 
 " 
 
 
 IX. 
 
 _ 
 
 1 
 
 1 
 
 23 
 
 
 May. 
 
 X. 
 
 - 
 
 1 
 
 1 
 
 24 
 
 
 
 XI. 
 
 _ 
 
 1 
 
 _ 
 
 _>. r 
 
 
 " 
 
 XII. 
 
 _ 
 
 1 
 
 _ 
 
 26 
 
 
 
 XIII. 
 
 
 _ 
 
 - 
 
 27 
 
 
 
 XIV. 
 
 
 _ 
 
 _ 
 
 28 
 
 
 
 XV. 
 
 
 _ 
 
 _ 
 
 29 
 
 
 
 XVI. 
 
 
 _ 
 
 _ 
 
 30 
 
 
 " 
 
 XVII. 
 
 
 - ! - 
 
 31 
 
 
 
 XVIII. 
 
 
 _ - 
 
 32 
 
 
 
 
 
 XIX. 
 
 
 - 
 
 
 
 
 Total, 
 
 23 
 
 9 4 
 
 For Tryptic Digestion of Intestinal and Appen/dical Extract. 
 
 
 
 
 
 Part of River. 
 
 Ke 
 
 
 
 
 
 Mouth. 
 
 Upper. 
 
 
 \ 
 
 1895. 
 
 July. 
 
 XI. 
 XIV. 
 
 1 
 
 1 
 
 
 3 
 
 
 December. 
 
 XXXIX. 
 
 1 
 
 - 
 
 
 4 
 
 
 
 XL 
 
 1 
 
 
 
 5 
 
 
 
 
 XII. 
 
 1 
 
 _ 
 
 
 ? 
 
 1896. 
 
 May. 
 
 XIII. 
 XIV. 
 
 1 
 1 
 
 - 
 
 
 8 
 
 
 
 XV. 
 
 1 
 
 _ 
 
 
 9 
 
 
 
 XVL 
 
 1 
 
 _ 
 
 
 10 
 
 
 
 XVII. 
 
 1 
 
 - 
 
 
 11 
 
 
 XVIII. 
 
 1 
 
 _ 
 
 
 12 ' 
 
 
 
 XIX. 
 
 1 
 
 - 
 
 
 
 
 Total, 
 
 11 
 
 1 

 
 26 Investigations on the Life-History 
 
 Table II. represents the same data arranged according to season 
 
 
 1 
 
 00 
 
 O 
 
 .0 
 
 ~ 
 
 0000 
 
 - 
 
 - 
 
 
 y 
 
 r-^-N 
 
 oc 
 
 ,0 
 
 - 
 
 O T? 'NO 
 
 * 
 
 3 
 
 
 "" 
 
 
 
 
 
 
 
 
 
 ,4 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 i rr i--. o 
 
 c-. 
 
 
 
 
 3 
 
 
 
 
 
 
 
 C*l 
 
 $ 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 ^ 
 
 C-3 
 
 -.-. 
 
 i-i - l^ O 
 
 
 
 
 1 
 
 c- 1 
 
 
 
 
 
 
 
 
 
 1 
 
 *. , 
 
 *- 
 
 u-0 
 
 - 
 
 o r: rj o 
 
 
 
 
 
 
 I 
 
 C CO 
 
 
 
 00 
 
 oo 
 
 r- rr -* o 
 
 OO 
 
 s 
 
 
 Z : 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ~ u 
 ^ i> 
 
 rj -7 o 
 
 70 
 
 o 
 
 71 
 
 O C 7*3 O 
 
 N 
 
 c 
 
 
 ^ 
 
 
 
 
 
 
 
 1 
 
 jj, 
 
 jj 
 
 
 
 1 
 
 
 
 
 
 
 1 
 
 5 
 
 
 
 
 
 
 
 ?5 ! 
 
 
 
 J5*. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 I 
 
 '43 
 
 
 
 
 
 
 
 
 
 1 
 
 5 
 
 1 
 
 r; CO 
 
 o 
 
 l-l I-I 
 
 o 
 
 i i 7C 7^ i 1 
 
 4 "^" 
 
 
 
 1 
 
 Oi CO 
 
 
 
 CO 
 
 
 
 COCO 
 
 
 
 s | 
 
 
 i 
 
 O CO 
 
 
 
 I--; rH 
 
 5O 
 
 MW.5*^ 
 
 
 
 s 
 
 
 f 
 
 
 3 
 
 
 1 
 
 .... 
 
 : 
 
 j. 
 
 
 1 
 
 rf 
 
 
 f 
 
 H 
 
 O s 
 
 H 
 
 1 
 
 
 
 g >.l 
 
 
 JC> be 
 
 
 fill 
 
 
 e 
 
 o 
 
 
 
 ri 
 
 
 M 
 
 
 *' 
 

 
 of the Salmon in Fresh Water. 27 
 
 3. METHODS. 
 
 The stomach and intestine of each fish used for the purpose of testing 
 the digestive activity were placed, after removal, in methylated spirits 
 for forty-eight hours to extract the excess of fatty matter, and to 
 harden the tissues. They were then taken out of the spirit, cut up into 
 small pieces, and placed in glycerine, to which a small quantity of water 
 had been added. After a month to six weeks the glycerine extract was 
 filtered off, and made up in each case to 50 cc. The stomachs and 
 intestines were treated separately. 
 
 The activity of the extracts was then determined in the usual way. 
 5 cc. of the extracts were added to 10 cc. of an egg-albumin solution 
 of known strength, hydrochloric acid or sodium carbonate mixed with 
 it, and the whole made up to 50 cc. by the addition of water. The 
 amount of hydrochloric acid added represented in each case the quantity 
 necessary to form an acidity of 0*1095 per cent, in the 50 cc., and the 
 sodium carbonate represented 1'5 per cent, in alkalinity. 
 
 Of the solutions 5 cc. were used to estimate the acidity or alkalinity 
 present, and the remaining 45 cc. were left at the ordinary temperature 
 of the laboratory for six to eight hours. 
 
 The solutions were then neutralised, boiled, and then acidified with 
 acetic acid, a few drops of a saturated solution of acetate of soda being 
 also added. The precipitate which formed was caught on a weighed 
 filter-paper, washed with boiling water, alcohol, and ether, and then 
 dried and weighed. The increase in the weight of the paper represented 
 the amount of albumin still undigested. This subtracted from the 
 original weight of the albumin employed gave the quantity digested. 
 Corrections were made in these figures for the amount of coagulable 
 proteid contained in the glycerine extract on several occasions at the 
 commencement of the research, but as the additional precipitate was 
 found to be so small, and to be practically constant, it has been ignored 
 throughout. 
 
 The diastatic power of the glycerine extracts was estimated by its 
 action on starch, a solution of iodine and iodide of potassium being 
 employed as the indicator. A 1 per cent, starch solution was made 
 faintly alkaline with sodium carbonate, 5 ccm. of the extract added, 
 and the mixtxire left for two hours at the temperature of the room. 
 
 No action was obtained from the gastric extracts, and the further 
 details of the experiments with these extracts are omitted. All the 
 intestinal and appendicical extracts proved to be fairly active. 
 
 4. DIGEST ON IN THE STOMACH. 
 
 () The Peptic Activity of the Glycerine Extracts of the Gastric 
 Mucous Membrane. 
 
 In Table III. the details of this part of the research are sum- 
 marised : 
 
 [TABLE.
 
 Investigations on the Life- History 
 
 TABLE III. 
 
 PEPTIC POWER. 
 
 1. From Mouth of Rivers. 
 
 
 Digestive ; A _: ri : tv ,,f 
 
 Xo. Number of Fish. 
 
 Season. Power. A ,"J" 
 
 
 | % Digested. 
 
 1 
 
 XV. 
 
 Mav, 1895 
 
 33-3 
 
 % 
 0-21 
 
 2 
 
 VII. 
 
 March, 1896 
 
 33-0 
 
 0-65 
 
 3 
 
 XVI. 
 
 May, 1896 
 
 22-2 
 
 0-13 
 
 4 
 
 XVII. 
 
 
 21-1 
 
 0-12 
 
 5 
 6 
 
 7 
 
 XXIX. 
 XXX. 
 
 XXXI. 
 
 October, 1895 
 
 ns-3 
 
 JlS'S 
 
 ll8-3 
 
 {0-24 
 0-24 
 0-24 
 
 8 
 
 VI. 
 
 March, 1896 
 
 12-9 
 
 0-61 
 
 9 
 
 XIII. 
 
 May, 1896 
 
 10-4 
 
 0-13 
 
 10 
 
 IV. 
 
 March, 1896 
 
 9-5 
 
 0-24 
 
 11 
 
 XL. 
 
 December, 1895 
 
 7-9 
 
 0-24 
 
 12 
 
 XVIII. 
 
 Mav, 1896 
 
 5'5 
 
 o-oi 
 
 13 
 
 I. 
 
 March, 1896 
 
 5-2 
 
 0-19 
 
 14 
 
 V. 
 
 
 2-6 
 
 0-41 
 
 15 
 
 XIX. 
 
 May, 1896 1-1 
 
 0-004 
 
 16 
 
 XI. 
 
 July, 1895 0-0 
 
 o-o 
 
 17 
 
 XII. 
 
 
 o-o 
 
 o-o 
 
 18 
 
 XIII. 
 
 
 o-o 
 
 0-006 
 
 19 
 
 II. 
 
 March, 1896 
 
 o-o 
 
 o-oi 
 
 20 
 
 III. 
 
 
 o-o 
 
 0-13 
 
 21 
 
 XIV. 
 
 May, 1896 
 
 o-o 
 
 o-o 
 
 22 
 
 XIX. 
 
 August, 1895 
 
 o-o 
 
 0-022 
 
 23 
 
 XXIV. 
 
 September, 1896 
 
 o-o 
 
 0-022 
 
 Total 23 
 
 9-5 % 0-167 
 
 Total with Digestive Power, 
 
 15 
 
 14-6% 
 
 0-244 
 
 2. From Upper Waters. 
 
 No. Number of Fish. 
 
 Season. 
 
 Digestive 
 Power. 
 % Digested. 
 
 Aciditv of 
 Extract. 
 
 1 XXXVII. 
 2 XXXVIII. 
 
 November, 1895 
 
 (14-7 
 \14-7 
 
 /0-17 
 "1 0-17 
 
 3 
 
 XI. 
 
 Mav. 1896 
 
 10-4 0-004 
 
 4 
 
 XII. 
 
 
 6-08 0-005 
 
 5 
 
 X. 
 
 July, 1895 0-0 O'Ol 
 
 Total 
 
 5 
 
 9-17 % 0-074 
 
 Total with Digestive Power, 
 
 4 11-8 % 
 
 0-174 
 
 3. Kelts. 
 
 X... Number of Fish. 
 
 Season. 
 
 Digestive 
 Power. 
 % Digested. 
 
 Aciditv of 
 Extract. 
 
 1 VIII. 
 
 March, 1S96 ( 33'9 fO-47 
 
 2 IX. 
 
 
 \33-9 "10-47 
 
 :! X. 
 
 May, 1896 
 
 21-7 0-15 
 
 4 XIV. 
 
 July, 1895 
 
 0-0 0-009 
 
 22-7 
 
 0-274
 
 of the Salmon in Fresh Water. 29 
 
 1 . FISH FROM THE ESTUARIES. Of the 23 fish caught at the mouth 
 of the rivers the glycerine extract of the gastric mucous membrane 
 possessed some peptic power in 15. The average percentage of 
 albumin digested in these is ] 4-6, while check experiments with 
 ordinary commercial pepsine, at the ordinary temperature and with the 
 same proportion of hydrochloric acid, show a digestive power reaching 
 to 72 per cent. Including all the fish caught at the mouth the 
 digestive activity only equals 9 -5 per cent. 
 
 2. FISH FROM THE UPPER WATERS. Four of the five fish from 
 the upper waters were found to give positive results in this part of the 
 research, with 11-8 per cent, of albumin digested. The total number 
 five give a percentage of 9- 17 per cent. 
 
 These results seem to indicate that the mucous membrane of the 
 stomach in the fish which have reached the upper waters of the rivers 
 possesses a somewhat smaller peptic power than that of salmon caught 
 close to the sea. 
 
 3. KELTS. The figures obtained from the four kelts show a higher 
 digestive activity than in the fish included in the first and second 
 classes namely, 22-7 per cent. One of the kelts, however, possessed no 
 proteolytic ferment in its stomach ; the remaining three possessed a 
 digestive power of 2 9 -8 per cent. The kelt without digestive power was 
 one which had not returned to the sea in July. 
 
 (b) Relation of Peptic Activity to Acidity. 
 
 A comparison of the percentage acidities of the extracts with their 
 proteolytic power shows a direct relationship between these, although 
 in several cases the relationship is departed from. In the fish 
 caught at the river mouths those in which an active digestion of 
 albumin w^as found, to a greater or less extent, the mean acidity of the 
 extracts of the stomachs reached 0*244 per cent, in terms of hydro- 
 chloric acid, against 0-023 per cent., or ten times as little, in those in 
 which 110 digestive action occurred. Similarly, of the five fish from 
 the upper waters the four presenting actual evidence of digestive 
 power give a mean acidity in their extracts of 0-074 per cent., the 
 remaining one a mean of only O'Ol per cent. 
 
 In Table IV. the figures relating to the comparison between the 
 amount of albumin digested and the acidity of the extracts are given 
 for the total number of fish used : 
 
 TABLE IV. 
 
 RELATION BETWEEN THE DIGESTIVE POWER AND THE ACIDITY. 
 Totals. 
 
 
 No. 
 
 Season. 
 
 Digestive Power.! 
 
 1 
 
 Acidity. 
 
 Total, 
 
 32 
 
 Whole Year. 
 
 7 
 11-1 
 
 0-166 
 
 Those with Digestive 
 Power, ... 
 With no Digestion, 
 
 22 
 10 
 
 - 
 
 16-13 
 
 0-231 
 0-0209 
 
 In the total number, 32, the digestive power averages 11-1 per cent., 
 the acidity 0-166 per cent. In the 22 with some actual digestive power 
 this reaches 16-13 percent., the acidity 0-231 per cent., while in the 
 10 fish in which no peptic digestion occurred the mean acidity is
 
 30 Investigations on the Life-History 
 
 only 0-0209 per cent. In the first two the proportion between the 
 umount of albumin digested and the acidity of the extract is exactly the 
 same. The acidity per cent, is 1-45 per cent, of the amount of albumin 
 acted on. 
 
 It would thus seem that the amount of active ferment extracted 
 from the gastric mucous membrane appears to be exactly proportional 
 to the acidity of the extract in the salmon examined in this research. 
 
 Table V. shows the figures relating to the peptic power and acidity 
 of the stomach extracts arranged as to season : 
 
 TABLE V. 
 
 FIGURES RELATING TO THE DIGESTIVE POWER AND THE ACIDITY. 
 ARRANGED AS TO SEASONS. 
 
 Season. 
 
 Dig^STKwer. ! Average Acidity. 
 
 March, ; 9 14-;") Q-:>;-,:\ 
 
 May and June, ; 10 13'1 0'07 
 
 July and August, 6 O'O O'OOS 
 
 September to December, 7 13'17 O'lH 
 
 The result is very striking. The fish examined in March give a 
 comparatively high digestive power with the highest acidity, those 
 captured in Miay-June and September-December present a lower 
 digestive power, identical in amount in both periods, though the 
 acidity present in the fish of the latter period is almost three times 
 that of those in former. The fish caught in July and August have m> 
 digestive power and a very low acidity. 
 
 (c) Relation of Peptic Activity to the Micro- Orya nisms present. 
 
 Table VI. is formed of figures relating to the fish in which both the 
 digestive power of the stomach mucous membrane and the number of 
 bacteria present were investigated. The bacteriological data will be 
 considered more fully later on, but a direct comparison between the 
 results of the two investigations is useful in this place : 
 
 [TABLE.
 
 3. 3- a 5" S <8 
 d d d d o' d
 
 of the Salmon in Fresh Water. 
 
 31 
 
 TABLE VI. 
 
 COMPARISON BETWEEN THE DIGESTIVE POWER AND THE ACIDITY OF THE 
 GASTRIC EXTRACTS, ARRANGED WITH REGARD TO THE MICRO- 
 ORGANISMS GROWN FROM THE STOMACH. 
 
 No. 
 
 Number of Colonies. 
 
 No. of 
 Fish. 
 
 Date. 
 
 Peptic 
 
 Activity. 
 
 Acidity of 
 
 Extract, 
 
 
 
 
 Tube I. 
 
 Tube II. 
 
 
 
 
 
 1 
 
 
 
 
 
 XXIX. 
 
 Oct. 1895 
 
 18-3 
 
 0-24 
 
 2 
 
 
 
 
 
 XXX. 
 
 
 18-3 
 
 0-24 
 
 3 
 
 
 
 
 
 XXXI. 
 
 
 18-3 
 
 0-24 
 
 4 
 
 1 Mould 
 
 
 
 V. ' Mar ."1896 
 
 2-6 
 
 0-41 
 
 5 
 
 1 Mould 
 
 
 
 III. ' 
 
 o-o 
 
 OM8 
 
 6 Several Moulds 
 
 
 
 I. 
 
 
 5-2 
 
 0-19 
 
 75, 3 Moulds, 2 
 
 7 Moulds 
 
 VII. 
 
 
 33-0 
 
 0-65 
 
 
 Liquefying 
 
 
 
 
 
 
 8 
 
 8, 5 Moulds, 3 
 
 1 Mould 
 
 IV. 
 
 
 1-8 
 
 0-24 
 
 9 
 
 Liquefying 
 12 Liquefying 
 
 1 Liquefying 
 
 II. 
 
 
 o-o 
 
 o-oi 
 
 10 
 
 Large Number 
 
 4 Moulds, 1 
 
 VI. 
 
 
 12-9 
 
 0-61 
 
 11 
 
 Liquefying 
 Larare Number Pure 
 
 Liquefying 
 
 
 XII. 
 
 July 1895 
 
 o-o 
 
 o-o 
 
 Growth B. Coli 
 
 
 
 
 
 
 12 
 
 Innumerable 
 
 200 (100 Coli) 
 
 X. 
 
 " 
 
 o-o 
 
 o-oi 
 
 13 
 
 
 53 ; 3 Coli 
 
 XI. 
 
 
 o-o 
 
 o-o 
 
 14 
 
 45 ; 3 Coli 
 
 XIII. 
 
 
 o-o 
 
 0-006 
 
 15 : 
 
 Large Number 
 
 XIV. 
 
 
 o-o 
 
 0-009 
 
 16 
 
 
 
 XXIV. 
 
 Aug!'l895 
 
 o-o 
 
 0-022 
 
 {3 None ^ March 7 
 3 Moulds only | July 5 
 3 Small Number f August 1 
 7 Large Number J October 3 
 
 7'4 
 
 0-187 
 
 Of the 3 with no Growth, ' 
 
 18-3 
 
 0-24 
 
 , 3 with Moulds only, 
 
 2-6 
 
 0-24 
 
 3 with a few Growths, 
 
 14-1 
 
 0-3 
 
 , 7 with a Large Number 
 
 1-84 
 
 0-094 
 
 , 1 no Liquefying Growth, 
 , 9 with Liquefying Growths, 
 
 o-o 
 
 6-26 
 
 o-o 
 
 0-17:5 
 
 In Chart I. the relationship between the acidity, peptic activity, and 
 bacterial contents of the stomach is graphically shown. 
 
 The first three fish noted yielded no bacteria of any kind from the 
 alimentary tract, while their peptic activity,, which was tested in 
 common, was high, and the acidity of their common extract above the 
 average. Three fish yielded growths of moulds only, and presented a 
 much lower peptic power, but a similar acidity. Three also gave 
 evidence of the presence of moulds, along with a small number of 
 true bacteria. Their digestive power was above the average but less 
 than in the first three, while the acidity in their extracts reached 0'3 
 percent. On the other hand, in the seven fish in which no digestive 
 action was observed, the bacteria were very numerous, and the acidity 
 low. The latter set were almost all captured during the months of 
 July and August. 
 
 These results appear to show that there is a direct connection between 
 the digestive activity and acidity of the stomach extract and the number 
 and form of organisms present. When the extract is acid and of con- 
 siderable digestive power organisms are either absent, or few in 
 number. When only a slight digestive power with a similar acidity 
 occurs, no organisms are present save moulds. Here the growth 
 of other organisms may be arrested by the growth of the moulds
 
 32 Investigations on the Life-History 
 
 contained in the contents. A low aridity and practically an extinct 
 power of peptic digestion coincides with the presence of large numbers 
 of micro-organisms. The fish from the stomachs of which no organisms 
 were cultivated were all caught in October at the river mouth, and 
 possessed a marked power of digestion and a high degree of acidity. 
 The three in which moulds alone were found also came from the 
 estuaries during March. The three with a few bacteria in addition to 
 moulds were caught at the same time of the year, but gave a higher 
 digestive activity. Of the seven in which innumerable bacteria were 
 found one was caught at the mouth in March, the others in Jury 
 and August, two in the upper waters, five at the river mouths. 
 
 The peptic digestion of the gastric extract was tested in five of the 
 fish from stomachs of which the Bacillus coli communis was obtained. 
 The extract was inactive in all, and showed only a trace of acidity. In 
 No. XII., 1895, the growth from the stomach proved to be a pure 
 cultivation of this organism. 
 
 Apart from the actual demonstration of the absence of food from the 
 stomach cavity in all the salmon examined, the slight acidity and small 
 digestive power of the extracts of the gastric mucous membrane recorded 
 lead to the conclusion that the fish both in the estuaries and in the 
 rivers were in a fasting condition. 
 
 (d) The Nature of the Acid present in the Gastric Extract. 
 
 Fifty ccin. of rectified spirit in which the chopped-up stomach of 
 Fish No. XXXIX., July, 1896, had been immersed, were distilled. 
 
 The first 40 ccm. which distilled over showed an acidity equal to 
 0-073 per cent, as HC1, but no hydrochloric acid was present. 
 Ufielmann's carbolo- ferric reagent was turned to a greenish-yellow hue. 
 The next 6 ccm. were neutral. 
 
 The remainder, 4 ccs., was shaken up with ether, and then an excess 
 of distilled water added. The water was removed from the ether by 
 means of a separation funnel. It amounted to 163 ccm. 100 ccs. 
 gave an acidity of '00438 per cent, with no free hydrochloric acid, both 
 the phloroglucin-vanillin and the dirnethyl-amido-azo-benzol tests 
 proving negative. On the addition of decinonnal hydrochloric acid to 
 24 ccm. in the presence of dimethyl -amido-azo-benzol 110 reaction occurred 
 until 0'6 ccm. had been run in, or until 0*082 per cent, of the acid had 
 combined with the substances present, which were previously free from 
 such an acid combination. The addition of nitrate of silver in the 
 presence of nitric acid to the 100 ccm. tested for acidity caused a 
 precipitate weighing after incineration 0'025 gramme, 0-013 grammes 
 of which was soluble in nitric acid, leaving 0*012 grammes of chloride 
 of silver. This is equal to 0-00305 grammes of hydrochloric acid, or the 
 chlorine present was 0-003 per cent., while 0-013 grammes of silver, 
 equal to 0-0204 grammes of silver nitrate, were combined to organic 
 bodies. The ether contained 0-00219 per cent, of acid, and on 
 evaporation of part of the solution and addition of water Ufielmann's 
 reagent was discoloured, leaving a very slight yellow tinge. 
 llesult, 50 ccs. 
 
 46 ccs. distilled ; acidity equal to 0-0292 grammes HC1. 
 4 ccs. remaining ; 0-00819 ., 
 
 Watery extract 163 ccm., acidity equal to 0-0071 grammes HC1. 
 
 Ether extract 50 ccm., 0-00109 
 
 Acidity of distillate, 0-0634 per cent. 
 
 Acidity of remainder, 0-2047 per cent. 
 
 Acidity of total 50 ccm., 0-07478 per cent, or 0-03739 gramme of acid.
 
 of the, Salman in Fresh Water. 33 
 
 The chlorine present in the form of chlorides or of hydrochloric acid 
 only amounted to 0*00489 grammes or -00978 per cent, as HC1, while 
 0*0148 grammes of hydrochloric acid had to be added before positive 
 evidence of free mineral acid was obtained, or 0*0296 per cent. If the 
 proportion of HC1, combining to proteid bodies be taken at 10 per cent. 
 (Of. Journ. Anat. and Phys, Vol. XXVII., p. 195} 0*148 grammes of 
 proteid was present unattached to this acid. 
 
 Similarly it was shown that 0*0204 gramme of silver nitrate combined 
 with organic material, which represents about 0*21 gramme of proteid. 
 
 From this stomach and its contents, therefore, no free mineral acid 
 was obtained, but only a small quantity of combined hydrochloric acid 
 and some organic acids. 
 
 The alcoholic extract of the chopped-up stomach of Fish No. XXVI., 
 June 1896, caught in the upper waters, was mixed with ether, 
 agitated, and then an excess of distilled water added. The water was 
 separated from the supernatant ether and distilled to dryness ; 0*00684 
 gramme of free hydrochloric acid was obtained in the distillate, and no 
 orgiiiiic acids were present. 
 
 The alcoholic extracts of the stomachs of three salmon caught in July 
 1895, a kelt, a fish which had been some time in fresh water, and a fish 
 caught at the river mouth, showed no evidence of the presence of free 
 hydrochloric acid, and were only slightly acid to litmus. 
 
 The gastric mucous membrane of salmon on their way to the 
 spawning beds yielded no free hydrochloric acid to the alcohol (90 per 
 cent.) in which it was immersed, but investigation showed the presence 
 of some hydrochloric acid in combination with organic material. The 
 alcoholic extract, however, contained a volatile organic acid which 
 readily distilled over, and an organic acid which did not pass off' on 
 distillation. In one fish caught in the upper waters in June a small 
 quantity of free hydrochloric acid was obtained from the alcoholic 
 extract of the stomach, after distillation to dryness. 
 
 The almost constant coincidence of an increased acidity of the 
 glycerine extract of the stomach with an enhanced digestive power must 
 be regarded as being independent of the presence or absence of 
 hydrochloric acid. Other acids are known to exert an appreciable 
 power when acting in the presence of pepsine, and presumably, there- 
 fore, are capable of converting to some extent the forerunner of that 
 ferment, pepsinogen, into active pepsine. The extracts were made 
 from the chopped-up walls of the stomach and its mucoid contents, 
 the acid present in the mucus and formed by bacterial action may 
 have acted on the pepsinogen and converted part of it into pepsine. 
 But the results of the bacteriological cultivations do not bear out this 
 theory, as, with two exceptions, the fewer the organisms the greater 
 was the power of the gastric extract. 
 
 Another difficulty, and a serious one, is afforded by the fact that the 
 glycerine extracts, although made after immersion in alcohol for 48 
 hours or more, varied greatly in acidity, though without the presence of 
 any bacterial decomposition. The peptic power with two exceptions 
 corresponded with the acidity as determined. 
 
 It is impossible to even hazard any theory to account for the 
 apparent paradox, and it only remains to state that the greater the 
 acidity the fewer organisms, and the greater the peptic power of the 
 ferment in the stomach, although the acidity of the extract may not 
 be due to free hydrochloric acid. 
 
 5. TRYPTJC DIGESTION. 
 
 In a few instances the activity of the tryptic ferment of the 
 c
 
 34 
 
 Investigations on the Life-History 
 
 intestinal mucous membrane or of the pyloric appendages was estimated 
 by its power of digesting egg-albumin in 2 per cent, sodium carbonate 
 at the ordinary temperature of the room. The extracts were made in 
 the same way as those from the stomach. To prevent any fallacy from 
 the growth of organisms during the digestive action a small quantity 
 of chloroform was added to each all the extracts possessed active 
 diastatic powers in alkaline solution. 
 
 One or two of the extmcts were also used in an acid solution con- 
 taining -12 per cent, of hydrochloric acid. No action was observed. 
 
 I. INTESTINAL Mucous MEMBRANE. 
 
 The results have been tabulated Table VII. and show a much 
 greater proportion of digested albumin than in the peptic experiments. 
 In two fish the intestinal walls and contents were used, one of them a 
 kelt. Both were caught in July, and show a digestive power equal to 
 16-9 and 12-6 per cent, respectively : 
 
 TABLE VII. 
 
 ESTIMATION OF THE PROTEOLYTIC ACTION OF THE GLYCERINE EXTRACT 
 OF THE INTESTINAL Mucous MEMBRANE, AND OF THE PYLORIC 
 APPENDAGES. 
 
 Fish Caught at the Mouth. 
 1. INTHSTINK. 
 
 
 
 Corresponding 
 
 
 n , Albumin 
 Digested %. 
 
 Means. 
 
 Proportion % 
 Digested by 
 Gastric 
 
 
 
 Extract. 
 
 
 ! <v 
 
 7 
 
 XI. 
 
 July, 1895 16 ? 9 
 
 16-9 % ? 
 
 2. Al'PKNDAUKS. 
 
 XXXIX. 
 
 December, 1895 j 42'9 
 
 j 
 
 
 
 XL. 
 
 28-1 
 
 
 7-9 
 
 XLI. 
 
 59-8 
 
 
 
 XIII. 
 XIV. 
 XV. 
 XVI. 
 XVII. 
 
 Mnv. 1896 51-0 
 31-6 
 54-4 
 69-7 
 477 
 
 (10)48-13% 
 
 . 
 
 10-4 
 
 o-o 
 
 33-3 
 22-2 
 21-1 
 
 XVIII. 
 
 40-7 
 
 
 5-5 
 
 XIX. 
 
 j 45-4 
 
 J 
 
 1-1 
 
 10 
 
 48-13 
 
 
 12-4 
 
 
 
 i Total Tested, 8 
 
 Fish Caught in the Upper 
 1. INTESTINE. 
 
 XIV. (Kelt) 
 
 July, 1895 
 
 12-6 
 
 12-6 % 
 
 o-o 
 
 Total, 12 
 
 
 12-5 
 
 9-95 
 ITotal Tested, 10 
 
 II. PYLORIC APPENDAGES. 
 
 The extract from the appendages was much more active than that of 
 the intestine. Three fish caught in December afforded an average of 
 43-6 per cent, of albumin digested, and seven captured in May, one of 
 48-64 per cent. The greatest powers were shown by No. XVI. with 
 69-7 per cent., No. XLI. 59-8 per pent., No. XV. 54-4 per cent., No. 
 XIII. with 51-0 per cent., and No. XVII. with 47-7 per cent. 
 
 The corresponding figures for the peptic power in these fish show 
 that the July fish with no peptic power have the smallest proportion of
 
 of the Salmon in Fresh Water. 35 
 
 albumin digested by trypsin. Of the five which digested most albumin 
 by the action of the appendical extract, four only were used for the 
 estimation of peptic digestion. These four give an average amount of 
 albumin digested by the extract from the appendages of 55'7 per cent., 
 and by the gastric extract of 21*75 per cent. This last figure is much 
 above the mean of 11-1 per cent, obtained from the total number of 
 estimations of the peptic power. 
 
 The smallest amount of albumin digested (12- 6 per cent.) was 
 obtained from the action of the intestinal extract of a kelt caught 
 in July, the next from that of an ascending fish in the same 
 month (16'9 per cent.). The average percentage of albumin digested 
 at the ordinary temperature by the extracts of the pyloric appendages 
 was 48-13 per cent. This fact shows that a very considerable proteo- 
 lytic power was still possessed by the secretion of the gland opening 
 into the appendages. Dr. Gulland has shown that this is of the nnt-urn 
 of a pancreas. 
 
 Although the intestines were invaria.bly found to be empty, save for 
 some mucus, the glandular elements in their walls, especially those in 
 the mucous membrane of the appendages, contained a much more 
 active zymogen than the gastric glands, and ^ were able to afford a 
 ferment, on the addition of an alkali, which was capable of a considerable 
 amount of work.
 
 36 Investigations on the Life-History 
 
 5. THE BACTERIOLOGY OF THE ALIMENTARY CANAL 
 OF THE SALMON. 
 
 A. LOCKHART GILLESPIE, M.D., F.R.C.P.ED., F.R.S.E. 
 
 At one time it was seriously argued that the rapidity of digestion in 
 fish is due to fermentative processes induced by bacterial forms. This 
 theory was promulgated at a time when the large proportion of pepsine 
 present in the gastric secretion of fish had not been ascertained. The 
 fallacy presented by this theory is at once apparent when the time 
 necessary for the bacterial decomposition of albuminous bodies, the 
 bodies which are digested in the stomach, is considered ; and especially 
 when it is remembered that the temperature at which most bacteria 
 grow is very much above that of the inner cavities in fishes. 
 
 The antiseptic action of an active and acid gastric juice has also been 
 demonstrated, and the general rule may be laid down that the more 
 active the gastric secretion and the greater its acidity the fewer bacteria 
 can pass unharmed into the intestine. 
 
 Miescher Ruesch, in the paper referred to in a preceding section (II.), 
 states categorically that the salmon caught in the upper reaches of the 
 Rhine show less tendency towards early decomposition in the bowel, 
 while those caught in tidal waters soon exhibit signs of putrefaction 
 there. He adduces no detailed evicfence in support of this statement, 
 but suggests that the non-occurrence of decomposition in the intestines 
 of salmon which have ascended a river is due to the fact that they do not 
 feed, and therefore do not swallow bacteria with their food, arguing 
 further that this absence of decomposition implies a self-imposed 
 abstinence from food for some time before entering fresh water. 
 
 The observations detailed below were undertaken for the purpose of 
 ascertaining the correctness of this statement, and to investigate the bac- 
 teriology of the alimentary canal in more detail. They include (1) an 
 estimation of the number of organisms cultivated from the alimentary 
 tract of the salmon ; (2) a rough classification of these organisms ; and 
 (3) a comparison between their numbers and form in different parts of 
 the rivers and at different times of the year. 
 
 1. MATERIAL USED. 
 
 Reference to Table I. shows that of the forty-one salmon employed 
 twenty -nine were captured at the mouth, and twelve, one of these a 
 kelt, in the upper reaches of the rivers : 
 
 [TABLE.
 
 of the Salmon in Fresh Water. 
 
 TABLE I. 
 
 TABLE OF FISH EMPLOYED. 
 For Bacteriological Cuttivativns. 
 
 
 
 
 
 Part of River. 
 
 
 No. 
 
 Year. 
 
 Month. 
 
 No. of Fish. 
 
 
 
 
 Kelts. 
 
 
 
 
 
 Mouth. 
 
 Upper. 
 
 
 1 
 
 1895. 
 
 July. 
 
 X. 
 
 
 1 
 
 
 2 
 
 5J 
 
 
 XI. 
 
 
 
 _ 
 
 3 
 
 * 
 
 
 XII. 
 
 
 
 
 4 
 
 
 
 
 XIII. 
 
 
 
 
 5 
 
 t| 
 
 
 XIV. 
 
 
 1 
 
 1 
 
 6 
 
 ,, 
 
 August. 
 
 XXI. 
 
 
 
 
 7 
 
 J? 
 
 
 XXII. 
 
 
 _ 
 
 _ 
 
 8 
 
 
 ); 
 
 XXIII. 
 
 
 _ 
 
 _ 
 
 9 
 10 
 
 
 
 September. 
 October. 
 
 XXIV. 
 XXVII. 
 
 
 1 
 
 - 
 
 11 
 
 
 
 XXIX. 
 
 
 
 
 12 
 
 
 ' 
 
 XXX. 
 
 
 
 _ 
 
 13 
 
 
 
 XXXI. 
 
 
 _ 
 
 _ 
 
 14 
 
 
 November. 
 
 XXXIII. 
 
 
 
 
 15 
 
 " 
 
 
 XXXV. 
 
 
 1 
 
 
 16 
 
 
 i 
 
 XXXVI. 
 
 
 
 _ 
 
 17 
 
 1896. 
 
 March. 
 
 I. 
 
 
 
 
 18 
 
 
 
 II. 
 
 
 
 
 19 
 
 
 
 III. 
 
 
 
 
 20 
 
 ' 
 
 
 IV. 
 
 
 
 _ 
 
 21 
 
 
 
 V. 
 
 
 _ 
 
 _ 
 
 22 
 
 
 
 VI. 
 
 
 _ 
 
 _ 
 
 23 
 
 
 
 VII. 
 
 
 
 
 24 
 
 | 
 
 May. 
 
 XXI. 
 
 
 1 
 
 _ 
 
 25 
 
 ; 
 
 
 XXIV. 
 
 
 
 _ 
 
 . 26 
 
 
 
 XXV. 
 
 
 _ 
 
 
 
 27 
 
 | 
 
 June. 
 
 XXVI. 
 
 
 1 
 
 _ 
 
 28 
 
 
 
 XXVII. 
 
 
 
 _ 
 
 29 
 
 f 
 
 
 XXXVIII. 
 
 
 1 
 
 _ 
 
 30 
 
 
 
 XXX [X. 
 
 
 
 _ 
 
 31 
 
 j 
 
 July. 
 
 XL. 
 
 
 . _ 
 
 _ 
 
 32 
 
 
 
 XLII. 
 
 
 1 
 
 _ 
 
 33 
 
 
 
 XLIII. 
 
 
 1 
 
 
 34 
 
 
 " 
 
 " 
 
 XLIV. 
 
 
 
 _ 
 
 35 
 
 ; 
 
 
 XLV. 
 
 
 _ 
 
 _ 
 
 36 
 
 
 October. 
 
 LXIX. 
 
 
 1 
 
 _ 
 
 37 
 
 | 
 
 
 LXX. 
 
 
 1 
 
 _ 
 
 38 
 
 f 
 
 , 
 
 LXXI. 
 
 
 
 _ 
 
 39 
 
 
 November. 
 
 LXXVI. 
 
 
 _ 
 
 _ 
 
 40 
 
 
 " 
 
 LXXVII. 
 
 
 J 
 
 _ 
 
 41 
 
 M 
 
 
 LXXVIII. 
 
 
 
 1 
 
 - 
 
 
 
 
 Total, 
 
 29 
 
 12 
 
 1 
 
 Table II. (at p. 26 of the preceding section) further divides the total 
 number into those caught at the river mouth and in the upper waters 
 during different seasons of the year. All the fish captured in March 
 came from the river mouths. During May and June four came from 
 the lower, and three from the upper reaches. The July and August 
 fish comprised nine from the river mouths, and four from the upper 
 waters; of those captured from September to December nine came from 
 the mouths and five from the higher parts. 
 
 2. METHODS. 
 
 In the case of each fish used for the purpose of determining the number 
 and character of the micro-organisms present in the alimentary canal, 
 " stick " cultivations were made on gelatine roll-tubes directly from the 
 contents of the oesophagus, the stomach, and the intestine. As nearly 
 
 285124
 
 38 Investigations on the Life-History 
 
 as possible the same amount of material was, in every case, taken by 
 means of a straight needle. Second roll-tubes were inoculated from these 
 in almost every case. 
 
 The colonies which appeared in the tubes were counted day by day after 
 Inoculation until their number became stationary, or so large as to be 
 countless, or until liquefaction of the gelatine prevented any further 
 enumeration. When rapidly-growing and liquefying colonies rendered 
 the gelatine fluid and inhibited the growth of the slower non-liquefying 
 forms, the number of the latter was estimated from their colonies 
 which began to grow before the liquefying growths had obscured 
 their further development. 
 
 When the colonies were too numerous to count they were noted 
 as being " in large numbers ; " when still more numerous, and covering 
 the whole surface of the gelatine with minute growths, they were termed 
 " innumerable." When it was wished to compare the relative numbers 
 cultivated from different classes of fish, actual figures had to be substi- 
 tuted for these terms. In each case 250 has been used to represent " a 
 large number," and 500 to represent " innumerable." The actual figures 
 were certainly higher than those chosen, but those used indicate a 
 somewhat definite proportion between the actual numbers present, and 
 their constant substitution introduces no important element of error. 
 
 In this part of the research valuable help was rendered by Mr. Hume 
 Patterson, the Laboratory Assistant. 
 
 I. NUMBER OF MICRO-ORGANISMS. 
 (a) The Salmon Caught at the Estuaries. 
 
 The chief details of the results obtained from the bacteriological in- 
 vestigation into the salmon caught in tidal waters are shown in Tables 
 II. and III. The results are grouped according to the season of the 
 year at which the observations were made. The number of the fish 
 corresponding to that in the general Laboratory register is first given, 
 and the year and month of capture are then noted: 
 
 [TABLES.
 
 of the Salmon in Fresh Water. 
 
 .5.5 
 SS 
 
 = .S 
 
 000 
 
 00 ;(MO>C>ICO 
 
 i | 
 
 4 \ 
 
 fl L 
 
 MSI in r 
 
 iPi"l ; v 
 
 it S X. 
 
 |1 
 S ^ 

 
 40 
 
 Investigations on the L 
 
 
 
 Intestine. 
 
 il I 
 ^ 
 
 1 " J ' - J | ' 
 
 Moulds . 
 B. Uoli Com. 
 
 i 
 
 , 
 
 1 
 
 
 a" 
 
 5 
 
 
 ** 5 2 
 
 5^ 
 
 2 
 
 Stomach. 
 
 3 - be 3 
 
 13 ! 1 1 jf ' 1 
 
 3 I II I 
 
 ,,. 1 11 Moulds 
 w \ 8 Liquefying 
 
 1-8 Colony 
 
 
 i 
 
 
 
 
 
 S 
 
 * 
 
 
 
 
 | 
 
 
 f 
 
 1 ' 1 ' ' .-i ' 
 
 It 
 
 >, 
 
 f 
 
 
 s 
 
 1 li 
 
 I-I 
 
 00 
 
 | 
 
 
 
 IL 
 
 1 
 
 
 1 
 
 
 1 
 
 1!H . 1 
 
 !li f 3 * ? 
 
 Ill 11 II 
 
 O c J 55 .= > O 
 
 S'-='S 
 
 III 
 
 | 
 
 o 
 
 S 
 
 
 I i l| 1 
 
 f 
 
 
 
 i 
 
 i 
 
 S 1 -c ^ S Sg ^ 
 
 1 ! 1 ;=l 11 it 
 
 | a |' =| -S-S 
 
 i 1 . 1 ! ! s 11 
 
 o 3 ^ ^ j 
 
 v , 7 / 20 Moulds 
 137 \117Li(iiiofyi 
 
 10-5 Colonies 
 
 
 1 1 
 
 
 
 
 
 I 
 
 f 1 ' 1 "I 1 
 II g 1 11 1 
 
 o S oo S ^ S 
 
 -( 22 Moulds 
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 41 
 
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 Investigations on the Life-History 
 
 
 
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 Investigations on the Life-History 
 
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 46 Investigations on the Life-History 
 
 Entries are made in Tables II. "and III. under the headings of 
 Tube I. and Tube II. of the number and character of the micro- 
 organisms grown from the three portions of the alimentary tract 
 investigated, the oesophagus, stomach, and intestine. At the end of 
 each of the four seasons into which the observations naturally fall, (1) 
 March, (2) May-June, (3) July and August., and (4) from September to 
 the end of the year, the approximate total number of growths is given, 
 followed by the average per fish. 
 
 Similarly the total number of liquefying and non-liquefying organisms 
 and the number of moulds are noted. 
 
 The results are graphically displayed in Charts I., II., and III. 
 
 In Chart I. the average number of organisms grown in the first 
 roll-tubes is given for each season and for each section of the alimentary 
 canal. The unbroken line represents the figures relating to the ceso- 
 
 gus, the broken line to those for the stomach, and the dot and dash 
 to the figures obtained from the intestine. 
 
 The method of representing the colonies when present in too large a 
 number to admit of accurate computation has already been given. 
 Moulds are included among the non-liquefying series owing to the com- 
 paratively long period which elapses before they affect the solidity of 
 gelatine. , 
 
 Chart II. has been constructed from the number of bacteria which 
 were grown at each season from the different sections of the digestive 
 canal, and which caused liquefaction of the gelatine medium. 
 
 The general form of the curves corresponds to that in the preceding 
 Chart. The number of organisms grown from the esophagus exceeds 
 the number cultivated from the other two sections during the months 
 of July and August in a marked manner. The chief point of difference 
 between the figures for the organisms which liquefy gelatine and those 
 for the total number lies in the larger proportion which of the former 
 recorded as grown from the intestine. 
 
 It necessarily follows that the converse is true of the mm -liquefy ing 
 organisms, and a glance at Chart III.' shows that fewer of these 
 organisms were grown from the intestine and a greater number from 
 the contents of the stomach. The figures for the oesophagus are practi- 
 cally the same in both cases. 
 
 The Charts show that the number of organisms present in the 
 oesophagus exceeded those in the other sections of the alimentary canal 
 in the latter half of the year. In March the numbers grown from the 
 intestinal contents exceeded those from the stomach by an average of 
 12, and those from the oesophagus by 21. The numbers during this 
 month were very low, while almost no growths were obtained from any 
 of the second tubes. In fact, the total number of colonies which 
 appeared in the second tubes inoculated from the three sections of the 
 canals of seven fish only reached 35, or five colonies a fish, and 1 -6 colonies 
 011 an average in each individual section! Still fewer i growths were 
 obtained from the salmon caught in May and June, an average of only 
 two in each oesophagus, 11-7 in each stomach, and 7'2 in each intestine. 
 The second tubes show a slightly larger number than in March, due to 
 the number of moulds present in them. 
 
 In the case of the fish captured in July and August, large numbers 
 of organisms were grown from each part :of the canal. ! A glance at 
 Chart I. shows that those cultivated from tlie contents of the oesophagus 
 are largely in excess of the numbers present in the stomach or intestine. 
 The numbers for the second tubes also show a great rise, except in those 
 from the intestine. In the later months of the year the colonies 
 grown fall below the numbers during Jujy and Augus^, but are still 
 : :
 
 PLATE II. 
 
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 of the Salmon in Fresh Water. 47 
 
 much more numerous than during the first half of the year. The mean 
 numbers in all of the three sections of the alimentary canal are the same 
 in those months when the results from the first roll-tubes are considered. 
 And it is a most noteworthy fact that in not one of the six fish from 
 which second tubes were made could a single growth be detected in the 
 cultivations from both the oesophagus and stomach, while only six 
 colonies in all, or one per fish, were obtained from the intestinal 
 contents. 
 
 From these data it appears that there is a distinct connection between 
 the temperature and the number of organisms present in the intestinal 
 tract of the salmon caught at the mouth of fresh-water streams or in 
 the tidal estuaries. The temperature of sea-water takes much longer 
 to rise as the months advance than the temperature of the air, and the 
 great increase in the number of bacteria cultivated during the months 
 of July and August corresponds with the period of the year at which 
 the temperature of shallow waters is near its maximum. The water in 
 the rivers of Scotland, and in a considerable portion of the sea close to 
 their mouths, must be affected in spring by the melted snow from the 
 hills, with the result that the temperature of the tidal water remains 
 low. Although the fish do not feed, they must swallow some of the 
 water. 
 
 (6) Salmon Caught in the Upper Waters. 
 
 Twelve salmon from the upper reaches were employed for the investi- 
 gation of the number of bacteria present in the alimentary canal. They 
 fall to be divided as to the season of capture into three classes. Three 
 were caught in May and June, four in July and August, and five in the 
 months from September to November (Table III.) 
 
 The results are depicted in Charts IV., V., and VI. in a similar way 
 to those obtained from the fish captured in tidal waters. 
 
 It is at once apparent that the same increase in the number of 
 organisms occurred in the months of July and August, that almost no 
 colonies were obtained in May and June, and that the bacteria found in 
 the alimentary tract during the later months, though much less than in 
 late summer, were more numerous than in the fish from the river- 
 mouth (Chart IV.) 
 
 In May and June the total number of colonies which appeared in the 
 roll-tubes was extremely small. Only twelve growths were cultivated 
 from the alimentary tracts of three fish in the first tubes, or four 
 apiece, and only four in the second tubes, all of which grew in the tubes 
 inoculated from the oesophagus. 
 
 The increase in the numbers in July and August is shared equally by 
 the oesophagus and stomach. The number grown from the intestinal 
 contents was smaller by about three-fifths than the number in either of 
 these sections. 
 
 hi the autumn months the drop in the figures is most marked in the 
 r;ise of the oesophagus, and least in the case of the intestine. 
 
 The two Charts following (Charts V. and VI.), in which the organisms 
 capable of liquefying gelatine have been separated from those incapable 
 of so doing, show that the increase in the number of colonies obtained 
 from the stomach contents in July and August is due to a predominance 
 of bacteria able to dissolve gelatine. The number cultivated from the 
 stomach exceeds that obtained from the oesophagus. 
 
 Practically no liquefying organisms were grown from any of the 
 sections during the first season, or from the intestine in the third 
 season of the year. During the last period, however, the colonies 
 from the stomach contents were numerous, those from the oesophagus 
 fewer, but still much above the number in the intestine.
 
 48 Investigations on the Life-History 
 
 The non-liquefying forms were obtained in numbers which, of course, 
 coincide with the differences between the figures given in Charts IV. 
 and V. Almost nil in May and June, the summer increase is most 
 marked in the oesophagus, and proportionally in the intestine, when 
 compared with the last chart; while the autumn decrease is greatest in 
 the oesophagus, less in the stomach, and least in the intestine, from 
 which, indeed, the same number of growths were obtained as in the 
 months of July and August. 
 
 (c) Kelts. . 
 
 Cultivations were made from the intestinal tract of one kelt, 
 caught in July 1895 in the upper reaches. Owing to the examination 
 of only a single specimen of this class of fish, the results have been 
 included in the preceding section. 
 
 A large number of non-liquefying growths were obtained from the 
 esophagus, of both liquefying and non-liquefying from the stomach and 
 intestine, the latter section containing a few bacilli coli communes. The 
 peptic activity of 'this fish was nil, the amount of albumen digested by 
 an extract of the intestine, 12-6 per cent. 
 
 (d) Differences Between the Numbers of Micro-Organisms Grown from the 
 Alimentary Tract in Salmon caught in the Estuary and of those 
 caught in the Upper Parts of the Rivers. 
 
 In the 12 fish from the upper waters, the following numbers of 
 organisms were counted : 
 
 Total, 
 Per Fish, 
 
 
 From the 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 Total. 
 
 
 1,826 
 
 2,277 
 
 1,419 
 
 5,522 
 
 
 152 
 
 189 
 
 118 
 
 460 
 
 in the 29 caught in the estuaries 
 
 Total, 
 
 3,185 
 
 1 
 
 2,267 
 
 2,197 
 
 7,649 
 
 Per Fish, 
 
 109-7 
 
 
 78-1 
 
 75-7 
 
 263-7 
 
 f 
 
 1 
 
 
 
 
 and in the total number of fish, i.e., 41 
 
 Total, 
 Per Fish, 
 
 5,011 4,544 
 
 122-2 110-8 
 
 3,616 
 
 13,171 
 321 
 
 In the total number of fish examined the oesophagus contained the 
 largest number of organisms, the intestine the least. 
 
 On the other hand, the colonies grown from the stomach contents of 
 the fish caught in the upper reaches were the most numerous, then the 
 colonies from the oesophagus, and those from the intestine. 
 
 The colonies obtained from the oesophagus in fish from the estuaries 
 presented a marked excess in numbers over those from the stomach 
 and intestines. The numbers in the latter were nearly equal. 
 
 [TABLE.
 
 of the Salmon in Fresh Water. 49 
 
 Table showing the number of Mia'o-Organisms grown from different 
 sections of the Alimentary Canal in Salmon caught in the Estuaries 
 and in the Upper Waters: 
 
 SEASON. 
 
 Number of Organisms per Fish. 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 July -August 
 From Upper Waters, . 
 From Mouth, 
 
 Difference. . 
 Difference per Cent, of 
 Upper- Water Figures, 
 
 September-November 
 From Upper Waters, . 
 From Mouth, 
 
 Difference, 
 Difference per Cent, of 
 Upper- Water Figures, 
 
 366 
 280-3 
 
 366 
 168-5 
 
 214-5 
 152-5 
 
 85-7 
 23-4 
 
 84-6 
 64.2 
 
 197-5 
 54-0 
 
 177 
 62-8 
 
 62-1 
 28-9 
 
 110-8 
 63-7 
 
 20-4 
 24-0 
 
 114-2 
 64-0 
 
 47-1 
 42-5 
 
 
 The proportion between the number of colonies found in the tubes 
 made from the oesophagus from July to November in the fish 
 from the upper reaches and the mouths of the rivers differ only slightly. 
 The number of colonies cultivated in autumn from the stomach 
 contents of the fish from the upper waters exceeds that of the 
 lower fish by 64 per cent, of its total, against 54 per cent, similarly 
 found in the summer fish. In like manner in autumn the excess of 
 organisms grown from the intestines of the upper-water fish over those 
 found in the fish from the estuaries constitutes 42'5 per cent, of their 
 number, compared with an excess of 28*9 per cent, from the same part 
 of the canal in the summer fish. 
 
 The only season in which the figures for the average number of 
 colonies grown from the alimentary canal of the salmon from the upper 
 parts of the rivers are less than those for the fish from the mouths is 
 that of May and June. During these months the excess in the number 
 of organisms grown from the fish caught at the mouth over the number 
 found in the others amounts to over 90 per cent, of the first number in 
 all parts of the digestive tract. 
 
 We may further say, then, that in early summer the bacteria 
 present in the alimentary tract of the salmon are less numerous when 
 the fish is in the higher reaches of rivers than when it is still in tidal 
 waters. On the other hand, the upper-water fish caught during 
 the next two months are characterised by a much greater increase in 
 the number of bacteria present in their alimentary canals, and conse- 
 quently show a marked excess in actual numbers of bacteria over those 
 in the fish at the river mouth. In the following months the rate of 
 decrease in the number of bacteria present is greater in the fish in 
 tidal waters, so that, although the organisms in the upper fish are not 
 nearly so numerous as in the preceding periods, the proportional excess 
 of bacteria in the upper- water fish over the number in those from the 
 mouth is increased. 
 
 The number of organisms in the mucus in the cesophageal tube 
 is practically the same in both sets of fish in May and June, but shows
 
 50 Investigations on the Life- History 
 
 in the upper-water fish an excess equal to about 24 per cent, of its total 
 over the figure foi the lower fish. 
 
 The colonies grown from the stomachs of the former class of fish were 
 si little less numerous in May and June than in the latter, but show an 
 enormous excess over those cultivated from the salmon caught at the 
 mouth in July and August, and ;i proportionately larger excess in the 
 next three months. 
 
 The figures for the colonies grown from the intestinal contents present 
 the same features as those for the stomach, hut in a less marked 
 manner. 
 
 (e) Relationship f Li<juef;jiny to ^on-Liquefying Organisms. 
 
 Turning to the figures given for the organisms winch liquefy gelatine 
 and for those which do not act on it in this way, when arranged in 
 relation to season and site of capture, we see in Chart VII., (in which 
 the red lines indicate the numbers of non-liquefying, the black lines 
 those of the liquefying growths per fish), that the two curves 
 representing the numbers of colonies grown from the oesophagus are 
 almost identical. The curves for the colonies grown from the stomach 
 show that in July and August the non-liquefying forms predominate, 
 and that in the later months they still are the more numerous. 
 
 In July and August the liquefying growths are in the greater number 
 in the intestine ; while from September to November they become less 
 numerous than the non-liquefying forms and moulds. 
 
 Chart VIII. shows more clearly the relative proportions between the 
 two classes of organisms. In it the percentage values are depicted : 
 that is, the percentage proportion of the liquefying organisms to the 
 total number of growths obtained in each section of the alimentary canal, 
 and at each period of the year. The black lines represent the result 
 of the cultivations from fish captured in the upper waters ; the red lines 
 from those from the mouth. 
 
 Save in the lines for the intestine in the fish from the upper waters, 
 and for the stomach in those from the mouths of the rivers, the general 
 tendency is for the curves to rise as the year advances. In May and 
 June liquefying organisms are practically absent, the 33' 3 per cent, for 
 the 03sophagus of the upper-water salmon representing only one out of 
 three growths. After a general rise in the percentage in July and 
 August arise which is least in the stomachs of the fish from the mouth 
 the curves representing the proportions still tend slightly upwards. 
 The oesophageal curve for the upper fish rises decidedly, the stomach 
 curve for these fish remains the same, while that representing the 
 colonies from the intestine in the fish from the mouth rises to 88 per 
 cent. The lines which denote a fall are 1, for the (esophagus of the 
 lower fish (and it is only slight), 2, for the stomach in the same 
 fish, and 3, for the intestine of the other class as already mentioned. 
 
 "When these curves are conjoined results are obtained (Chart IX.) 
 which show more plainly the greater proportion of liquefying growths 
 in the second part of the year. This proportion falls slightly in the 
 oesophagus and stomach after July and August. 
 
 In March, during which no fish were received from the upper waters. 
 the number of the liquefying organisms much exceeded that of the other 
 class 383 to 53, or 87 per cent, of the total. They were most numen >us 
 in the intestine, least in the oesophagus. 
 
 Adding the totals together for both classes of organisms totals which, 
 it must be borne in mind, are largely empirical, we find tliat the organ- 
 isms grown from 41 fish numbered 13,176, of which 6687 were moulds 
 or did not liquefy gelatine, leaving 6480 organisms capable of dissolving
 
 PLATE IV. 
 
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 tage of Liquefying Organisms to 
 in the Salmon from the River 
 hs and the Upper Waters. 
 May July September 
 and and to 
 June. August. November. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 \ 
 
 
 s 
 
 
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 /' 
 
 /' 
 
 
 
 
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 apable of Liquefyii 
 uefying contrasted 
 
 September to 
 November. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 /^ 
 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 3 
 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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 ^ 
 
 
 
 
 
 Number of Organisms c 
 Gelatine and Non Lie 
 
 May and July anc 
 June. August. 
 
 
 
 
 
 
 
 
 
 
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 X 
 
 x x^ 
 
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 S, {? 8 & t?
 
 of the Salmon i/i Fresh Water. 51 
 
 it. From each fish 321 colonies were obtained, or an average of 107 
 from each section of the alimentary canal. 
 
 In March the average number of colonies obtained from all parts of the 
 ti-.ict was 62 ; in May and June, 13-7 ; in July and August, 697 ; and 
 September to November, 255. It is difficult to account for the larger 
 number obtained from the fish caught at the river mouths in March 
 than from those captured during May and June, especially as during the 
 latter month several of the fish came from the higher reaches. 
 
 CONCLUSIONS. 
 
 From these observations it would appear that the alimentary tract of 
 the salmon in tidal waters, preparatory to ascent of the rivers, contains 
 a smaller number of bacteria than the tract of those fish which have 
 proceeded up the streams. The number of growths obtained from the 
 oesophagus of the lower fish is below that found in the upper fish (27 per 
 cent.), from which fact it may be concluded that fewer organisms are 
 swallowed, but that the difference is not very great. The greatest 
 contrast between the results for the two classes of fish is presented by 
 the figures for the growths cultivated from the stomachs. Fewer 
 colonies were obtained from the stomachs of the lower-water fish 
 than of the upper, while the liquefying bacteria formed the larger part 
 of the colonies in the case of the upper fish. 
 
 Mie.scher Ruesch affirms the exact opposite. He finds that the salmon, 
 from the upper reaches do not decompose so quickly as the lower fish; 
 due, he suggests, to the small number of organisms swallowed by the 
 upper fish while fasting. Direct experiment shows that the 
 putrefactive bacteria are more numerous in the upper fish than in the 
 lower, as well as affording evidence of the greater number of all bacterial 
 forms in these fish. Although the upper-water salmon may not feed, 
 they must swallow some of the water of the streams more or less 
 frequently. The variations observed are most probably due to the pro- 
 portion of organisms in the surrounding water more numerous in the 
 fresh water than in the tidal waters, and consisting of a greater number of 
 liquefying or putrefactive forms. That the diminution in the numbers of 
 organisms in the alimentary canal below the (esophagus is much more 
 O>arked in the lower fish than in the upper cannot be due to any in- 
 creased effect of gastric digestion, is shown by the smaller percentage of 
 albumin digested by their extracts. The acidity, however, of the gastric 
 extracts of the lower fish is slightly in excess of the acidity found in the 
 upper salmon ; while the number of non-liquefying colonies, although 
 actually less numerous, are, relatively to the total, in a much higher 
 proportion. 
 
 These facts seem to lead to the following conclusions : 
 
 1. Fewer organisms are swallowed by salmon in tidal waters. 
 
 2. A larger proportion of these organisms are non-putrefactive and 
 acid-forming. 
 
 3. The presence of these non-putrefactive organisms in excess of the 
 liquefying forms prevents the rapid growth of the latter. 
 
 4. As the members of the putrefactive class of bacteria grow much 
 more quickly than the bacteria forming the other class, fewer colonies 
 can be obtained from each part of the canal. 
 
 5. The proportion between the total number of organisms grown from 
 the stomach and intestine in the lower and upper fish did not differ so 
 much in the warm summer months as during the late autumn, when 
 the colonies, grown from these sections in tne upper fish, largely 
 exceeded the number grown from those in the fish caught at the mouth. 
 
 6. Of all the fish examined, the organisms weie very much more
 
 52 Investigations on the Life-History 
 
 numerous in those caught in July and August than in those caught in 
 spring, or even in May and June. The autumn fish contained a greater 
 number than the spring, but fewer than the summer fish. 
 
 2. GENERAL CHARACTERS OF THE MICRO-ORGANISMS CULTIVATED. 
 
 (a) Absence of Micro-Organisms. 
 
 In three fish, all caught in October (one in the upper waters) no 
 organisms appeared in any of the tubes : 
 
 TABLE IY. 
 
 GIVING THE KESULTS OF THE BACTERIOLOGICAL CULTIVATIONS. 
 1. No Organisms Groivn from the Alimentary Canal. 
 
 
 No. Date. 
 
 Part of River. 
 
 1 
 
 XXVII. 
 
 24th October, 1895. 
 
 Upper. 
 
 2 
 
 XXIX. 
 
 28th October, 1895. 
 
 Mouth. 
 
 3 
 
 XXX. 
 
 28th October, 1895. 
 
 Mouth. 
 
 2. No Organisms Grouni from 
 
 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 1 
 
 XXIV. 
 
 1895 
 Sept. 4 
 
 Mouth. 
 
 1 
 
 XXXI. 
 
 1895 
 Oct. 28 
 
 Mouth. 
 
 1 
 
 XIII. 
 
 1895 1 
 July 25 Month. 
 
 2 
 
 XXXI. 
 
 Oct. 28 
 
 
 
 2 
 
 XXXIII. 
 
 Nov. 9 
 
 
 
 2 
 
 XXI. 
 
 Aug.17 
 
 
 
 3 
 
 XXXV. 
 
 Nov. 24 
 
 Upper. 
 
 8 
 
 XXI. 
 
 1896 
 May 26 
 
 Upper. 
 
 3 
 
 XXII. 
 
 Aug.23 
 
 
 
 1 
 
 XXIV. 
 
 May 29 
 
 Mouth. 
 
 4 
 
 XXXVIII. 
 
 June 9 
 
 n 
 
 4 
 
 xxrv. 
 
 Sept. 4 
 
 . 
 
 5 
 
 LXIX. 
 
 Oct. 27 
 
 Upper. 
 
 6 
 
 XLV. 
 
 July 18 
 
 Mouth. 
 
 5 
 
 XXXIII. 
 
 Nov. 9 
 
 " 
 
 
 
 
 
 6 
 
 LXXVII. 
 
 Nov. 7 
 
 
 
 
 
 i. 
 
 Mar. 6 
 
 
 
 
 
 
 
 
 
 
 
 7 
 
 V. 
 
 Mar. 6 
 
 
 
 
 
 
 
 
 
 
 
 8 
 
 XXV. 
 
 May 30 
 
 
 
 
 
 
 
 
 
 
 
 9 
 
 XXXIX. 
 
 June 10 
 
 
 
 
 
 
 
 
 
 
 
 
 I 
 
 3. Only Moulds Grown from 
 
 Oesophagus. 
 
 Stomach. 
 
 Intestine. 
 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 1 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 1 
 
 II. 
 
 1896 
 Mar. 6 
 
 Mouth. 
 
 XXII. 
 
 1895 
 Aug.23 
 
 Mouth. 
 
 1 
 
 VII. 
 
 1896 
 Mar. 6 
 
 Mouth. 
 
 2 
 
 III. 
 
 
 
 
 2 
 
 XXXVI. 
 
 Nov. 23 
 
 >. 
 
 2 
 
 xxrv. 
 
 May 29 
 
 
 
 3 
 
 IV. 
 
 
 
 
 
 3 
 
 I. 
 
 1896 
 Mar. 6 
 
 
 
 3 
 
 XXXVIII. 
 
 June 9 
 
 Upper. 
 
 4 
 
 V. 
 
 , 
 
 
 
 4 
 
 III. 
 
 a 
 
 M 
 
 4 
 
 XXI. 
 
 May 26 
 
 
 
 5 
 
 VII. 
 
 
 
 
 5 
 
 V. 
 
 
 
 Jf 
 
 
 
 
 
 8 
 
 XXI. 
 
 May 26 
 
 Upper. 
 
 6 
 
 XXVI. 
 
 June 2 
 
 Upper. 
 
 
 
 
 
 ; 
 
 XXV. 
 
 May 30 
 
 Mouth. 
 
 7 
 
 XXVII. 
 
 it 3 
 
 Mouth. 
 
 
 
 
 
 a 
 
 XXVI. 
 
 June 2 
 
 Upper. 
 
 8 
 
 XXXIX. 
 
 10 
 
 ,, 
 
 
 
 
 
 9 
 
 XXXIX. 
 
 June 10 
 
 Mouth. 
 
 
 
 XLIV. 
 
 July 16 
 
 '- 
 
 
 

 
 of the Salmon in Fresh Water. 
 
 TABLE IV'. Continued. 
 4. No Bacteria Liquefying Gelatine Grown from 
 
 (Non-liquefying forms, with or without moulds, present.) 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 
 No. 
 
 Date. 
 
 Part of 
 Eiver. 
 
 1 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 1 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 1 
 
 XII. 
 
 1895 
 July 25 
 
 Mouth. 
 
 XII. 
 
 1895 
 July 25 
 
 Mouth. 
 
 X. 
 
 1895 
 July 25 
 
 Upper. 
 
 2 
 
 XIV. 
 
 
 
 Upper. 
 
 2 
 
 XXXV. 
 
 Nov. 24 
 
 Upper. 
 
 2 
 
 XXXVI. 
 
 Nov. 23 
 
 Mouth. 
 
 3 
 
 4 
 
 XXI. 
 XXII. 
 
 Aug. 17 
 23 
 
 Mouth. 
 
 3 
 
 4 
 
 XXV. 
 XL. 
 
 189G 
 May 30 
 
 July 9 
 
 Mouth. 
 
 3 
 4 
 
 XXXV. 
 
 III. 
 
 24 
 1896 
 Mar. 6 
 
 Upper. 
 Mouth. 
 
 5 
 
 XXXIII. 
 
 Nov. 9 
 
 M 
 
 5 
 
 LXXI. 
 
 Oct. 27 
 
 
 
 5 
 
 XXVII. 
 
 June 3 
 
 M 
 
 6 
 
 XXXVI. 
 
 ,, 23 
 1896 
 
 
 
 6 
 
 LXXVI. 
 
 Nov. 7 
 
 
 
 6 
 
 XLV. 
 
 July 18 
 
 
 
 r 
 
 XXVII. 
 
 June 3 
 
 
 
 
 
 
 
 7 
 
 LXXVIII. 
 
 Nov. 7 
 
 Upper. 
 
 8 
 
 XL. 
 
 July 9 
 
 
 
 
 
 
 
 8 
 
 XL. 
 
 July 9 
 
 Mouth. 
 
 9 
 
 LXXVI. 
 
 Nov. 7 
 
 
 
 
 
 
 
 
 
 
 5. Organisms similar to, or identical with, Bacillus Coli Communis. 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 
 No. Date. 
 
 Part of 
 River. 
 
 1 
 
 NO. 
 
 Date. 
 
 Part of 
 River. 
 
 1 
 
 X. 
 
 1895 
 July 25 
 
 Upper. 
 
 1 
 
 X. 
 
 1895 
 July 25 
 
 Upper. 
 
 XI. 
 
 1895 
 July 25 
 
 Mouth. 
 
 2 
 
 XI. 
 
 ,, 
 
 Mouth. 
 
 2 
 
 XI. 
 
 
 
 Mouth. 
 
 2 
 
 XII. 
 
 
 
 
 3 
 
 XII. 
 
 
 
 
 
 3 
 
 XII. 
 
 
 
 
 
 3 
 
 XIV. 
 
 
 
 Upper. 
 
 4 
 
 XIII. 
 
 
 
 ,, 
 
 4 
 
 XIII. 
 
 
 
 4 
 
 XXIII. 
 
 Aug. 31 
 
 Mouth. 
 
 5 
 6 
 
 XXII. 
 XXIII. 
 
 Aug,23 
 31 
 
 
 
 5 
 6 
 
 XXIV. 
 LXX. 
 
 Sept. 4 
 1896 
 Oct. 27 
 
 Upper. 
 
 5 
 6 
 
 XXXVI. 
 VI. 
 
 Nov. 23 
 1896 
 Mar. 6 
 
 " 
 
 
 
 
 
 
 
 
 
 7 
 
 LXIX. 
 
 Oct. 27 
 
 Upper. 
 
 6. Micro-organisms which Liquefied Gelatine were Grown from 
 
 1. IN ALL PARTS. 
 
 
 No. 
 
 Date. 
 
 Part of River. 
 
 1 
 
 XI. 
 
 25th July, 1895. 
 
 Mouth. 
 
 2 
 
 XXIII. 
 
 31st August, 1895. 
 
 ,, 
 
 8 
 
 VI. 
 
 6th March, 1896. 
 
 ,, 
 
 4 
 
 XLII. 
 
 14th July, 1896. 
 
 Upper. 
 
 
 XLHI. 
 
 16th July, 1896. 
 
 
 C 
 
 LXX. 
 
 27th October, 1896. 
 
 "
 
 Investigations on the Life-History 
 TABLE IV. Continued. 
 
 2. ONLY IN 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 
 No. 
 
 Date. 
 
 Part of 
 River. 
 
 1 
 
 X. 
 
 1895 
 July 25 
 
 Upper. 
 
 ! 
 
 X. 
 
 1895 
 July 25 
 
 Upper. 
 
 1 
 
 XII. 
 
 1895 
 July 25 
 
 Mouth. 
 
 8 
 
 XIII. 
 
 
 
 Mouth. 
 
 2 
 
 XIII. 
 
 
 
 Mouth. 
 
 2 
 
 XIV. 
 
 
 
 Upper. 
 
 :! 
 
 I. 
 
 1896 
 Mar. 6 
 
 ' 
 
 3 
 
 XIV. 
 
 .. 
 
 Upper. 
 
 3 
 
 XXXI. 
 
 Oct. 28 
 
 Mouth. 
 
 4 
 
 XXXVIII. 
 
 June 9 
 
 Upper. 
 
 4 
 
 XXI. 
 
 Aug.17 
 
 Mouth. 
 
 4 
 
 II. 
 
 Mar. 6 
 
 tl 
 
 I 
 
 XLIV. 
 
 July 16 
 
 Mouth. 
 
 5 
 
 XXIV. 
 
 Sept. 4 
 
 ' 
 
 5 
 
 XXVI. 
 
 June 2 
 
 Upper. 
 
 6 
 
 XLV. 
 LXXI 
 
 18 
 
 " 
 
 6 
 
 II. 
 
 Mar. 6 
 
 
 
 6 
 
 7 
 
 XLIV. 
 LXIX 
 
 July 16 
 
 Oct 27 
 
 Mouth. 
 
 s 
 
 LXXVII. 
 
 Nov. 7 
 
 
 
 8 
 
 VII. 
 
 
 
 
 
 8 
 
 LXXI. 
 
 
 Mouth. 
 
 9 
 
 LXXVIII. 
 
 
 
 Upper. 
 
 9 
 
 XXIV. 
 
 May 29 
 
 
 
 9 
 
 LXXVI. 
 
 Nov. 7 
 
 
 
 
 
 
 
 10 
 
 LXIX. 
 
 Oct. 27 
 
 Upper. 
 
 10 
 
 LXXVII. 
 
 
 
 
 
 
 
 
 
 11 
 
 LXXVIII. 
 
 Nov. 7 
 
 " 
 
 11 
 
 IV. 
 
 Mar. 6 
 
 - 
 
 No growths were obtained from the oesophagus in five fish four of 
 which were caught during the later months of the year, and one in May. 
 Two of the fish, during the autumn months, were from the upper reaches. 
 Similarly the tubes were sterile which were made from the stomach in 
 six fish three from the upper waters in November, May, and Jime, 
 three in October and November from the mouth. The nine fish from 
 whose intestines no growth, was obtained were all caught at the mouth 
 two in March, one in May, one in June, one in July, two in August, 
 one in September, and one in November. 
 
 (b) Moulds. 
 
 In many instances the colonies observed were entirely made up of 
 moulds : thus in nine cases from the oesophagus, in the same number from 
 the stomach, and in four from the intestine, this class of organism was 
 present alone. 
 
 In the fish caught at the river mouths in March the appearance of 
 moulds, apart from other growths, was frequent : thus in the oesophagus 
 of five fish, in the stomach of three, and in the intestine of one caught 
 during March, only moulds developed in the tubes. The majority of the 
 other instances of such single growth occurred in May and June, only 
 three belonging to a later period of the year. All the five fish which 
 belong to this class (from the upper reaches) were captured in June. 
 
 to 
 
 of Liquefying Bacteria. 
 
 No bacteria capable of liquefying gelatine were grown from different 
 sections of the alimentary tract in several fish. This class includes the 
 cultivations in which non-liquefying bacteria, either alone or along with 
 moulds, were present. 
 
 In one fish caught at the river mouth, in July 1896, no liquefying 
 colonies were observed in any of the tubes made from its alimentary 
 tract. The oesophageal contents were free from liquefying colonies in
 
 of the Salmon in Fresh Water. 
 
 55 
 
 nine fish, one of them from the upper water ; the gastric. contents in six 
 fish, one of them from the upper water in November 1895 ; and the 
 intestinal contents in eight, with three from the same part of the rivers 
 one in July and two in November. The fish included in this class 
 may be divided into : 
 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 Total. 
 
 [arch, . 
 
 
 
 
 
 1 
 
 1 
 
 Eay, 
 
 
 
 1 
 
 
 
 1 
 
 une, 
 
 1 
 
 
 
 1 
 
 2 
 
 uly, . . 
 
 3 
 
 2 
 
 3 
 
 8 
 
 .ugust, . 
 
 2 
 
 
 
 
 
 2 
 
 ctober, . 
 
 . 
 
 1 
 
 
 
 1 
 
 oyember, 
 
 3 
 
 2 
 
 3 
 
 8 
 
 Total, . 
 
 9 
 
 6 
 
 8 
 
 23 occasions. 
 
 (d) Bacillus Coli Communis. 
 
 Among the growths which did not liquefy gelatine there were a 
 number closely resembling in the form of their colonies and in their 
 microscopic appearance the Bacillus coli communis. It is now recognised 
 that several organisms may be included under this name. The 
 individual differences between the varieties are very slight. 
 
 The Bacillus coli communis was found in. the ossophagus and in the 
 stomach in six fish, in the intestines in seven. In two of these (which 
 were caught at the river mouth in July) the organism was detected in 
 each section of the digestive canal. In many of these other organisms 
 were also present. 
 
 All the fish from which this bacillus could be cultivated from the 
 (esophagus were caught during July and August ; and, in four of the 
 fish caught during these months, from the stomach and intestine. The 
 other occasions on which it was present were diiring the later months 
 except for one in March. Only four of the fish came from the upper 
 waters. 
 
 3. SPECIAL CHARACTERISTICS OF SOME OF THE MICRO-ORGANISMS 
 CULTIVATED FROM THE CONTENTS OF THE ALIMENTARY CANAL. 
 
 (a) Organisms which Liquefy Gelatine. 
 
 The varieties of bacteria capable of liquefying gelatine which were 
 found in the mucus of the alimentary canal may be divided into one or 
 two types : 
 
 1. Bacilli liquefying gelatine in " stich " cultures, and producing a
 
 56 
 
 Investigations on the Life-History 
 
 dirty yellow-red deposit at the bottom of the tube, very similar in 
 appearance to Ihe sediment in urine due to amorphous urates. The 
 cultures soon acquired a disagreeable odour. Under the microscope long 
 thin motile bacilli were seen, many of them in pairs, or chains ; very 
 similar to the " roter " bacillus found in water. 
 
 This class of organism was confined entirely to the salmon sent in for 
 examination in July and August, 1895. 
 
 The actual fish from which they were obtained were as follows : 
 
 
 CEsophagus. 
 
 Stomach. 
 
 Intestine. 
 
 Fish from the 
 Mouth - 
 
 Fish from the J 
 Upper Water [ 
 
 XIII. (1895), 
 July. 
 XX1I1. (1895), 
 August. 
 XIV. (1895), 
 July. 
 
 XXI. (1895), 
 August. 
 
 XIY. (1895), 
 July. 
 
 XI. (1895), 
 July. 
 XII. (1895), 
 August, 
 XIV. (1895), 
 July. 
 
 2. Micro-organisms liquefying gelatine and forming a white deposit 
 at the lower end of the tubes. 
 
 In one or two instances these organisms were further examined. In 
 No. XIII., July 25, 1895, very frvely motile bacilli, their length in 
 relation to their breadth being 2| as to 1, were found in the stomach. 
 They frequently were present in pairs. The gelatine was very rapidly 
 liquefied, and rendered strongly alkaline. 
 
 Organisms rapidly liquefying gelatine and forming a white flocculent 
 deposit were grown from : 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 X. (1895) July. 
 
 XIII. (1895) July. 
 
 XXXI. (1895) October. 
 
 XIII. 
 
 XIV. 
 
 XXVI. (1896) June. 
 
 V. (1896) March. 
 
 XXIV. Septr. 
 
 XLII. July. 
 
 XXXVIII. June. 
 
 XXIV. (1896) May. 
 
 XLIII. ,, 
 
 XLII. July. 
 
 XLII. ,, July. 
 
 XLIV. ,, 
 
 XLIII. 
 
 XLIII. 
 
 LXXI. October. 
 
 XLIV. 
 
 LXXVIII. Novr. 
 
 LXXVII. ,, Novr. 
 
 XLV. 
 
 
 
 LXXI. October. 
 
 
 
 LXXVII. Novr. 
 
 
 
 LXXVIII. 
 
 
 
 3. Organisms colouring the liquefied -gelatine light yellow, and forming 
 a bright yellow deposit :
 
 of the Salmon in Fresh Water. 
 
 57 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 XIII. (1895) July. 
 
 XI. (1895) July. 
 
 VI. (1896) March. 
 
 VI. (1896) March. 
 
 VI. (1896) March. 
 
 LXIX. October. 
 
 LXX. October. 
 
 VII. 
 
 LXX. 
 
 
 LXIX. ., October. 
 
 
 
 LXX. 
 
 
 4. Large dense creamy colonies slowly liquefying the gelatine into hole,-- 
 with sharp edges, no pigment formed. Very minute bacteria : 
 
 XI. 
 XXIII. 
 
 XXIII. 
 
 XI. 
 XXIII. 
 
 5. Bacilli liquefying gelatine and forming a light yellow deposit without 
 colouring the supernatant fluid : 
 
 I. 
 
 X. 
 
 II. 
 
 
 II. 
 
 IV. 
 
 
 IV. 
 
 
 (b) Organisms not Liquefying Gelatine. 
 
 1. Bacillus coli communis (cf. Table IV., 5, p. 53). 
 
 2. Small round yellow colonies, formed by short bacteria, often in 
 pairs, with rounded ends, very like micrococci, some in zoogloea. The 
 outer ends of those joined in pairs stain a darker colour. The pigment 
 formed was very bright in colour, and the growths were raised above the 
 surface of the gelatine in a similar manner to those of yeasts. 
 
 This bacterium was grown from the oesophagus of Fish No. XII., 
 July 1895, No. XXVII., June 1396, No. LXX., October 1896 ; from 
 the stomach of Nos. XXIV. and XXV., May 1896, No. LXX.. 
 October 1896 ; and from the intestine in Fish No. VI., March 1896, 
 No. XXVI., June 1896, No. LXIX. and No. LXX. in October 1896. 
 
 3. Small round yellow colonies of cocci, which were usually present in 
 the form of diplococci ; the growths were raised on the surface, and like 
 nail heads. 
 
 These diplococci were only found on two occasions, both during the 
 month of November 1895, in the oesophagus of No. XXXIII. and of 
 No. XXXVI. Both these fish were caught in the lower waters. 
 
 4. Organisms forming creamy moist circular colonies on gelatine. The 
 growths were white, faintly tinged with yellow in colour, raised on the 
 surface of the gelatine, circular and moist. The organisms present were 
 small non-motile bacteria, many of them looking like dumb-bells. They 
 were found along with colonies of a very similar appearance, but which 
 liquefied the gelatine, in the cesophagus of Fish No. XI., 1895, and in
 
 58 
 
 Investigations on the Life-History 
 
 the stomach of Fish No. XXV., the intestine of No. XXVII., and the 
 esophagus of No. XXXVIII., 1896. 
 
 5. Small white colonies whose nature was not further determined. 
 These occurred in a great number of the tubes. 
 
 (c) Yeasts, Moulds, and Sarcince. 
 
 Very few organisms akin to the yeasts were found. In No. 36, 
 November 1895, a yellow torula was giwvn from the intestine, a yellow 
 sjircinae from the intestine of No. 35, in the same month, and in the 
 stomach of No. 70, October 1896, 20 yellow yeasts or torulse were found. 
 
 The members of the mould class were much more numerous. Table 
 IV. gives a list of the sections in which moulds were the only organisms 
 grown. In the case of the oesophagus, cultivations of moulds alone were 
 almost entirely confined to the late autumn months, in the stomach to 
 three out of six the same applies, while in the intestine the season has 
 little to do with their appearance, two occurring in March, two in May 
 and June, three in July and August, and two in the later months. 
 Five of these fish were caught in the upper water. 
 
 Examination of Table V., giving some of the results of the 
 bacteriological investigations in the fish caught at the river mouth, 
 shows that moulds were most numerous in the fish caught in March, 
 May, and June : 
 
 TABLE V. (See also Table III). 
 
 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 Total. 
 
 March, - 
 
 7 Fish. 
 
 22 Moulds. 
 16 Greenish. 
 4 White. 
 
 20 Moulds. 
 11 Greenish. 
 8 White. 
 1 Purple. 
 
 5 Moulds. 
 5 Greenish. 
 
 47 
 
 May and June, 
 
 4 Fish. 
 
 4 Moulds. 
 4 Greenish. 
 
 34 Moulds. 
 33 Greenish. 
 1 White. 
 
 27 Moulds. 
 All white. 
 
 6.') 
 
 July and Aug.. 
 
 September to 
 November, 
 
 9 Fish. 
 9 Fish. 
 
 30 Moulds. 
 White. 
 
 None. 
 
 2 Moulds. 
 
 White. 
 
 1 White mould 
 
 None. 
 
 None. 
 
 32 
 
 3-2 
 
 1 
 
 
 29 
 
 56 
 
 57 
 
 145 
 
 Similarly the fish caught in the upper water gave results a^ 
 follows : 
 
 
 (Esophagus. 
 
 Stomach. 
 
 Intestine. 
 
 May and June - 
 
 3 Fish. 
 
 2 White moulds. 
 
 2 White moulds. 
 
 3 White moulds. 
 
 July and August 
 
 September to 
 November 
 
 4 Fish.^j 
 5 Fish.J 
 
 None. 
 
 None. 
 
 None. 
 
 
 12 
 
 2 
 
 2 
 
 3 =7
 
 of the Salmon in Fresh Water. 
 
 59 
 
 Moulds were therefore much more common in the fish caught in tidal 
 waters, and in the earlier part of the year, than in those from the upper 
 reaches or captured in autumn. The number found in the oesophagus 
 and stomach were much in excess of those grown from the intestinal 
 contents. 
 
 (d) Micro-Organisms in Two Series of Fish. 
 
 An interesting series of cultivations was obtained from a group of 
 fish sent in on the 5th of November 1896, from the mouth of the Spey. 
 Their numbers are 76, 77, and 78 : 
 
 No. 76 - 
 
 No 78 - 
 
 (Esophagus. 
 
 300 non-liquefying 
 spreading colonies. 
 
 d. 
 
 Gelatine rapidly 
 liquefied with a 
 white deposit. 
 
 h. 
 
 As in No. 77. 
 
 Stomach. 
 
 Intestine. 
 
 Innumerable small : Gelatine rapidly 
 
 colonies, a pure j liquefied. White 
 
 growth. Non- ; deposit, 
 liquefying. 
 
 e. 
 No growths. 
 
 As in oesophagus. 
 
 As in (esophagi 
 
 Innumerable, no 
 liquefying growths. 
 Pure cultivation. 
 
 The organisms in c, d, /, h, and i were identical. They liquefied 
 gelatine, forming a pure white precipitate, and consisted of small motile 
 bacilli, some of them joined together in chains. 
 
 The growths in b and j were also identical. Innumerable small pin- 
 head colonies, not liquefying the gelatine, and showing no variations 
 when grown in second dilutions. The organisms were very short, small, 
 plump bacteria, almost like cocci, immotile, and all of the same size. 
 
 No growth appeared in e. 
 
 The organism present in a was a short, broad bacterium, in many 
 instances gathered into zoogloefe, in others prolonged into long jointed 
 filaments. It was non-motile and did not liquefy gelatine. 
 
 In these three fish caught at the same place and on the same date 
 surprising variations in the number and nature of the organisms occur. 
 No rule seems to guide either the number or the forms present, either 
 when one fish is contrasted with another, or when succeeding sections 
 of the alimentary canal are compared. 
 
 Another interesting group of fish was sent in on October 27, 1896. 
 No. 69, from the upper Helmsdale ; No. 70, from the upper Dee ; and 
 No. 71, from the mouth of the Dee : 
 
 [TABLE.
 
 60 
 
 Investigations on the Life- 
 
 (Esophagus. 
 
 No. 69 - 
 
 No. 70 - 
 
 N 71 - 
 
 - ! None. 
 
 d. 
 
 13 bright yellow 
 liquefying. 
 
 60 yellow non-lique- 
 fying and 100 
 minute colonies, 
 probably the same 
 as last. 
 
 9 liquefying with a 
 white deposit. 
 
 Stomach. 
 
 Intestine. 
 
 b. 
 
 Innumerable. 
 Yellow 
 
 and lion-liquefy- 
 
 ing. 
 
 25 coli communis, 
 30 yellow liquefying. 
 20 yellow yeasts. 
 50 small yellow non- 
 liquefying. 
 
 4 small white non- 
 liquefying. 
 
 2 coli communin ; 12 
 bright yellow 
 
 liquefying ; 30 
 opaque yellow noii- 
 liquefying. 
 
 9 small yellow lique- 
 fying. 
 
 2 liquefying with a 
 white deposit. 
 
 50 small white non- 
 liquefying. 
 
 In the two fish from the upper reaches, tubes b, c, d, e, and /showed 
 the presence of a liquefying organism, a small, short, and thin bacillus, 
 which coloured the fluid portion of the medium a bright yellow, and 
 produced a deposit of a similar colour. The third fish presented none 
 of this variety. The organism which did not liquefy the gelatine in b, 
 e, <Z, and e also gave a yellow colour to its growths. Its characters have 
 already been described. In c and e a few colonies of the Bacillus coli 
 communis were found, and iii e some yellow yeasts. 
 
 No. 71 possessed no organism producing pigment, and the number of 
 colonies cultivated from it were small iii number. 
 
 CONCLUSIONS. 
 
 No very definite statement can be made in connection with the 
 character of the organisms cultivated. The characters of the growths 
 varied much more than the total numbers. The entire absence of 
 growths from the whole tract was noted in three fish, all caught in 
 October, and from sections of the tract on 20 occasions in 17 fish, only 
 four of which were caught during the months of July and August. 
 
 Similarly no organisms, save moulds, were grown from 22 separate 
 sections in 16 fish, only two belonging to fish caught during these 
 months. 
 
 These two facts point to the frequent absence of organisms, other 
 than moulds, from the water during the greater part of the year. 
 
 Forms of bacteria capable of liquefying gelatine by their growth were 
 absent in eight sections out of a possible 30 in fish caught in July, in 
 two out of nine in August, and eight out of 21 sections in November. 
 In March and October they were seldom absent. 
 
 Cultivations consisting entirely of non-liquefying forms were most 
 common in November and July. 
 
 Of the total cultivations, containing non-liquefying forms alone, five 
 only were from upper-water fish, and of these two were caught in July 
 and August. 
 
 That is to say, that out of 36 cultivations made from the segments of 
 the alimentary tract of fish from the upper water, five, or nearly 14 per
 
 of the, Salmon in Fresh Water. 
 
 61 
 
 cent., were free from liquefying growths, and of these, two occurred 
 in July out of 12 tested, or 16 per cent. Of the 87 cultivations 
 made from the fish from the mouth, 18 developed no liquefying 
 colonies, or 20-7 per cent. Of the 18, eight were obtained in July and 
 August, out of 27 cultivations, or about 29 per cent. ; six in late autumn 
 out of 27, or 22 per cent. ; three in May and June out of 12, or 25 per 
 cent. ; and one in March out of 21. 
 
 But to obtain the correct figures, the number of occasions on which 
 no growths or moulds only were present should be deducted' from the 
 total numbers. Doing this we find that no liquefying organisms were 
 found in : 
 
 
 March. 
 1 in 10 (10%) 
 
 May and 
 June. 
 
 July and 
 August. 
 
 September to 
 November. 
 
 Upper Water 
 Lower Water 
 
 3 in 4 (75%) 
 
 2 in 12 (16-6%) 
 8 in 21 (38%) 
 
 3 in 11 (27 -2%) 
 6 in 18 (33-3%) 
 
 Thus it is clear that colonies of bacteria which liquefy gelatine and 
 cause putrefaction are much more frequently absent in the fish caught in 
 the tidal waters than those caught in the upper reaches of the river. 
 
 If the numbers of the cultivations in which no organisms, only 
 moulds, or only non -liquefying forms, developed, be added together, we 
 find the following : 
 
 
 March. 
 
 May and 
 June. 
 
 7 in 9(77-7%) 
 11 in 12 (91 -6%) 
 
 July and 
 
 August. 
 
 September to 
 November. 
 
 Upper Water - 
 Lower Water 
 
 12 in 21 (57-1%) 
 
 2 in 12 (16-6%) 
 14 in 27 (51 -6%) 
 
 7 in 15(46-6%) 
 15 in 27 (55-5%) 
 
 A total in the upper-water fish of 16 in 36, or 44-4 per cent., and 
 in the lower of 52 in 87, or nearly 60 per cent. 
 
 Putrefactive organisms are therefore less common in the alimentary 
 tract of salmon living in tidal waters throughout the year, while they 
 are almost entirely absent in fish caught in May and June either at the 
 mouth or the upper reaches of rivers. 
 
 The Bacillus coli communis was grown on 19 occasions, 14 of these 
 occurring in July and August. Five cultivations from fish caught in 
 the upper waters contained this organism. 
 
 On several occasions fish caught on succeeding days, or a short time 
 after one another, afforded evidence of the presence of the same 
 organism. Thus the same diplococcus was given from two fish caught 
 in November 1895. 
 
 Moulds are more common in the alimentary tract of fish living in 
 tidal waters, especially during the earlier part of the year. 
 
 The two series, each of three fish, which are separately noted, show- 
 that the bacteriological conditions may be very different in salmon 
 caught about the same date. In the first series the three fish were 
 captured on the same day and at the same place, but the colonies grown 
 from them differ in both character and distribution. In the second 
 case two of the fish came from the same river, one from the mouth and 
 one from the upper part, the third from the upper part of another
 
 02 Investigation* on the Life-History 
 
 stream ; yet the two fish from the upper reaches contained an identical 
 small liquefying organism, and the Bacillus coli oonvmunis, neither of 
 which was grown from the third fish from the river mouth. 
 
 The two main factors which influence the number and nature of the 
 bacteria in the alimentary tract of the salmon when in tidal waters 
 preparing to ascend fresh-water streams, or during this ascent, appear 
 to be, 1 , the season of the year, including of course in this the influence 
 of the temperature of the water, and, 2, the number and nature of the 
 organisms present in the water. To suggest that organisms swallowed 
 with food can cause an increased tendency to early decomposition 
 appeal's to be not in accordance with the fact that the gastric juice of 
 fish when feeding contains much more acid than is required to destroy 
 or inhibit all organisms, especially those putrefactive forms which are 
 easily effected by the agent. When fasting the acidity is not sufficient 
 to kill the organisms which enter with the water swallowed ; when 
 feeding, many of the organisms fail to survive the action of the acid in 
 the secretion of the gastric glands. Tidal water must, contain fewer 
 organisms capable of living in the alimentary tract than fresh water.
 
 of the Salmon in Fresh Water. 63 
 
 R CHANGES IN THE WEIGHT AND IN THE CON- 
 STITUENTS OF THE MUSCLES, GENITALIA, 
 AND OTHER ORGANS DURING THE SOJOURN OF 
 THE SALMON IN FRESH WATER. 
 
 <i. CHANGES IN WEIGHT AND CONDITION OF SALMON 
 AT DIFFERENT SEASONS IN THE ESTUAR1KS 
 AND IN UPPER REACHES OF THE RIVERS. 
 
 BY D. NOEL PATON, M.D., F.R.C.P.ED., 
 
 AND 
 
 JAMES C. DUNLOP. M.D.. F.R.C.P.ED. 
 
 Further light is thrown upon the question of whether fish continue to 
 feed in the sea as their genitalia develop, and whether they feed after 
 entering the river, by the study of the differences in the condition of 
 the fish at the mouth and in the upper reaches of the various rivers 
 throughout the season. 
 
 Such an investigation also helps to clear up various problems in regard 
 to the migrations of salmon. If there is anything like a general to and 
 fro passage of the fish from the upper waters to the sea and back 
 throughout the season, then the fish at the mouth and fish in the upper 
 reaches will not be sharply marked off from one another. If such 
 migrations do not occur to any extent, then the fish in the upper reaches 
 may be expected to manifest characters different to those in the estuaries. 
 
 FEMALE SALMON, 1896. 
 
 Table I. gives the length in centimetres, the weight, -weight of mu.sc-U-, 
 and weight of ovaries, both actual and per standard fish, of the female 
 fish examined in grammes : 
 
 [TABLE.
 
 64 
 
 Investigations on the Life-History 
 
 TABLE I. 
 
 May and June. 
 ESTUARY. 
 
 
 River. 
 
 
 Weight. 
 
 Weight of Muscle. 
 
 Weight of Ovaries 
 
 
 
 
 Actual 
 
 PerStd. 
 
 Fish. 
 
 Actual 
 
 Per Std. 
 Fish. 
 
 Actual 
 
 PerStd. 
 Fish. 
 
 14 
 
 Helmsdale 
 
 73 
 
 3,610 
 
 9,281 
 
 2,404 
 
 6,180 
 
 40 
 
 103 
 
 15 
 
 Spey 
 
 73 
 
 3,650 
 
 9,385 
 
 2,340 
 
 6,016 
 
 42 
 
 108 
 
 10 
 
 Dee . . 
 
 75 
 
 3,990 
 
 9,456 
 
 2,530 
 
 5,995 
 
 40 
 
 95 
 
 17 
 
 Spev 
 
 79 
 
 4,295 
 
 8,714 
 
 2,710 
 
 5,498 
 
 43 
 
 87 
 
 18 
 
 Dee . . 
 
 71 
 
 3,775 
 
 10,540 
 
 2,370 
 
 6,619 
 
 52 
 
 145 
 
 20 
 
 Helmsdale 
 
 73 
 
 3,935 
 
 10,120 
 
 2,620 
 
 6,736 
 
 66 
 
 144 
 
 22 
 
 Spey 
 
 73 
 
 4,100 
 
 10,540 
 
 2,670 
 
 6,864 
 
 48 
 
 123 
 
 j:: 
 
 D*3 . . 
 
 67 
 
 3,425 
 
 11,390 
 
 2,174 
 
 7,228 
 
 16 
 
 68 
 
 24 
 
 Annan . 
 
 83 
 
 6,418 
 
 11,220 
 
 4,302 
 
 7,524 
 
 70 
 
 122 
 
 25 
 
 Helmsdale 
 
 74 
 
 4,095 
 
 10,100 
 
 2,660 
 
 6,568 
 
 70 
 
 173 
 
 27 
 
 Dee 
 
 73 
 
 3,795 
 
 9,757 
 
 2,444 
 
 6,284 
 
 57 
 
 147 
 
 29 
 
 Dee 
 
 68 
 
 3,020 
 
 9,605 
 
 1,760 
 
 5,598 
 
 47 
 
 150 
 
 :30 
 
 Annan . 
 
 78 
 
 5,915 
 
 12,470 
 
 3,900 
 
 8,219 
 
 83 
 
 17!> 
 
 35 
 
 Annan 
 
 70 
 
 3,434 
 
 10,010 
 
 2,280 
 
 6,646 
 
 71 
 
 207 
 
 UPPEU WATER. 
 
 
 
 I i 
 
 
 | 
 
 1! 
 
 Spey 
 
 69 2,840 8,642 
 
 1,860 
 
 5,659 
 
 34 
 
 104 
 
 1-2 
 21 
 
 Spey . . 
 Helmsdale . 
 
 75 3,740 8.863 
 76 4,055 1 9,239 
 
 2,354 
 2,690 
 
 5,578 
 6,128 
 
 57 
 97 
 
 135 
 
 221 
 
 28 
 
 Helmsdale 
 
 73 4,107 
 
 10,550 2,700 
 
 6,942 
 
 114 
 
 293 
 
 31 
 
 Spey . . 
 
 74 3,550 
 
 8,762 
 
 2,212 
 
 5,461 
 
 122 
 
 301 
 
 32 
 
 Dee 
 
 85 1 5,447 
 
 8,872 
 
 3,290 
 
 5,358 
 
 255 
 
 415 
 
 33 
 
 Dee 
 
 73 3,520 
 
 9,048 
 
 2,234 
 
 5744 
 
 144 
 
 370 
 
 
 
 1 
 
 
 
 
 July and August. 
 ESTUARY. 
 
 
 
 Weight. 
 
 Weight of Muscle. 
 
 Weightof Ovaries 
 
 River. 
 
 Length. 
 
 
 
 
 
 
 Actual 
 
 Per Std. 
 Fish. 
 
 Actual 
 
 Per Std. 
 Fish. 
 
 Actual 
 
 PerStd. 
 Fish. 
 
 Dee 
 
 78 
 
 4,752 
 
 10,010 
 
 3,074 
 
 6,477 ' 126 
 
 266 
 
 Dee 
 
 71 
 
 3,810 
 
 10,640 
 
 2,508 
 
 7,004 
 
 39 
 
 109 
 
 Dee 
 
 70 
 
 3,820 
 
 11,140 
 
 2,210 
 
 6,443 
 
 150 
 
 437 
 
 Dee 
 
 79 
 
 5,345 
 
 10,840 
 
 3,370 
 
 6,836 
 
 135 
 
 274 
 
 Spey . 
 
 75 
 
 4,225 
 
 10,010 
 
 2,646 
 
 6,270 
 
 66 
 
 156 
 
 Helmsdale 
 
 71 
 
 4,545 
 
 12,700 
 
 3,024 
 
 8,447 
 
 73 
 
 204 
 
 Annan . 
 
 77 
 
 5,165 
 
 11,310 
 
 3,404 
 
 7,456 
 
 
 202 
 
 Dee 
 
 80 
 
 5,170 
 
 10,090 
 
 3,434 
 
 6,707 
 
 162 
 
 316 
 
 S? : 
 
 74 
 81 
 
 4,336 
 
 5,875 
 
 10,700 
 11,050 
 
 2,840 
 3,680 
 
 7,009 
 6,923 
 
 80 
 158 
 
 197 
 297 
 
 Annan . 
 
 82 
 
 5,300 
 
 9,614 
 
 3,460 
 
 6,276 
 
 130 
 
 236 
 
 Spey 
 
 79 
 
 5,065 
 
 10,280 
 
 3 090 
 
 6,269 
 
 236 
 
 479 
 
 Spey . 
 
 94 
 
 9,780 
 
 11,780 
 
 6*248 
 
 7,525 
 
 258 
 
 311 
 
 UPPER WATEK. 
 
 
 
 
 
 
 
 
 
 
 37 
 
 Spey . 
 
 77 
 
 4,010 
 
 8,782 
 
 2,430 
 
 5,322 
 
 161 
 
 353 
 
 42 
 
 Spey 
 
 72 
 
 3,504 
 
 9.391 
 
 2,160 
 
 5,789 
 
 214 
 
 574 
 
 4-J 
 
 Helmsdale 
 
 66 
 
 2,532 
 
 8,806 
 
 1,532 
 
 5,331 
 
 103 
 
 358 
 
 4V 
 49 
 52 
 
 Dee 
 
 Helmsdale 
 Helmsdale 
 
 72 
 70 
 73 
 
 3,800 
 3,490 
 4,035 
 
 10,180 
 10,170 
 10,370 
 
 2,320 
 2,164 
 2,470 
 
 6,218 
 6,310 
 6,351 
 
 258 
 160 
 241 
 
 691 
 467 
 
 620
 
 of the Salmon in Fresh Water. 
 
 65 
 
 TABLE I. Continued. 
 
 October and November. 
 
 ESTUARY. 
 
 
 
 
 Weight. 
 
 Weight of Muscle. 
 
 Weight of Ovaries 
 
 fa 
 
 River 
 
 Length. 
 
 
 
 
 
 
 
 Actual |^ s |td. 
 
 Actual 
 
 Per Std. 
 Fish. 
 
 Actual 
 
 Per Std. 
 Fish. 
 
 6f> 
 
 72 
 
 a? 
 
 87 
 89 
 
 8,520 
 7,214 
 
 12,940 
 10,230 
 
 4,800 
 4,790 
 
 7,290 
 6,794 
 
 1,025 
 70 
 
 1,557 
 99 
 
 7;j 
 
 Dee 
 
 90 
 
 8,184 
 
 11,230 
 
 4,314 
 
 5,920 
 
 1,160 
 
 1,592 
 
 74 
 
 Deo 
 
 91 
 
 8,134 
 
 10,800 
 
 4,554 
 
 6,045 
 
 990 
 
 1,314 
 
 7ti 
 
 77 
 79 
 
 Spey . 
 Spey 
 Helmsdale 
 
 87 
 81 
 88 
 
 6,890 
 6,775 
 7,415 
 
 10,470 
 12,750 
 10,870 
 
 3,250 
 4,030 
 5,010 
 
 4,937 
 7,582 
 7,350 
 
 1,270 
 425 
 43 
 
 1,929 
 799 
 63 
 
 These fish are considered more fully on p. 85, and are not included in Table II. 
 
 UPPER WATER. 
 
 62 
 
 Helmsdale 
 
 74 
 
 3,700 
 
 9,133 
 
 1,658 
 
 4,093 
 
 822 
 
 2,029 
 
 6:5 
 
 Helmsdale 
 
 74 
 
 3,460 
 
 8,541 
 
 1,504 
 
 3,712 
 
 750 
 
 1,851 
 
 61 
 
 Dee 
 
 69 
 
 3,270 
 
 9,956 
 
 1,490 
 
 4,537 
 
 694 
 
 2,113 
 
 66 
 
 Helmsdale 
 
 73 
 
 3,845 
 
 9,886 
 
 1,650 
 
 4,242 
 
 844 
 
 2,170 
 
 67 
 
 Helmsdalo 
 
 68 
 
 2,875 
 
 9,145 
 
 1,210 
 
 3,849 
 
 635 
 
 2,019 
 
 6!) 
 
 Helmsdale 
 
 74 
 
 4,080 
 
 10,070 
 
 1,610 
 
 3,974 
 
 1,100 
 
 2,715 
 
 70 
 
 Dee 
 
 66 
 
 2,675 
 
 9,307 
 
 1,140 
 
 3,967 
 
 590 
 
 2,053 
 
 78 
 
 Spey . . 
 
 84 
 
 6,595 
 
 11,130 
 
 2,700 
 
 4,555 
 
 1,712 
 
 2,888 
 
 The analysis of such a Table shows : 
 (a) Weight. 
 
 1. The weight per fish of standard length of salmon coining to the 
 mouth of the river increases throughout the season. 
 
 TABLE II. 
 
 Showing Average Weight per Fish of Standard Length of Esttuiry 
 Salmon (see footnote) : 
 
 
 Spey. 
 
 Helms- 
 dale. 
 
 Dee. 
 
 Annan. 
 
 Average. 
 
 Limits of 
 Variation. 
 
 May and June, 
 
 9546 
 
 9834 
 
 10149 
 
 11233 
 
 10185 
 
 871412470 
 
 July and August, 
 
 10692 
 
 12700 
 
 10628 
 
 10460 
 
 10781 
 
 961012700 
 
 Oct. and Nov., 
 
 12053 
 
 10 870 
 
 11015 
 
 - 
 
 11648 
 
 1027012940 
 
 t Single fish. 
 
 The average in table was calculated by adding the weight per standard fish of all the fish of 
 period, and dividing by the number of fish. It is not an average of the rivers. 
 
 Mr. Archer, from his analysis of the Berwkk-on-Tweed figures 
 (Fishery Reports, Part II., 1895), concludes that fish coming to; the 
 mouth of the river gain in weight to the extent of 3 per cent, from May 
 to August. In our series the increase was 5*8 per cent. The statistics 
 at his disposal did not enable him to study the change after August. 
 
 2. Salmon in the upper reaches are lighter than those at the mouth, 
 and this difference increases a& the season advances, and is nearly twice 
 as great in October and November as earlier in the season.
 
 66 Investigations on the Life- History 
 
 TABLE III. 
 
 Showing Average Weight per Fish of Standard Length of Upper- Water 
 Snlmon : 
 
 
 Spey. 
 
 Helms- 
 dale. 
 
 Dee. 
 
 Average. 
 
 Limit of 
 Variation. 
 
 May and June, 
 
 8756 
 
 9895 
 
 8960 
 
 9139 
 
 864210550 
 
 July and August, 
 
 9086 
 
 9782 
 
 *10180 
 
 9616 
 
 878210370 
 
 Oct. and Nov. 
 
 *11130 
 
 9355 
 
 9631 
 
 9646 
 
 854111130 
 
 *One fish. 
 
 TABLE IV. 
 
 Showing Average per Fish of Standard Length of all the Rivzrsfrom 
 Tables II. and III : 
 
 
 Estuary. 
 
 Upper 
 
 Water. 
 
 Difference. 
 
 May and June, 
 
 10185 
 
 9139 
 
 1046 
 
 July and August, . 
 
 10781 
 
 9616 
 
 1165 
 
 Sept. and Oct., 
 
 11648 
 
 9646 
 
 2002 
 
 (b) Muscle. 
 
 3. Fish coming to the mouth of the river have, in July and August, 
 a slightly greater amount of muscle, per fish of standard length, than 
 fish in May and June, and a distinctly greater amount than fish in 
 October and November. 
 
 TABLE V. 
 
 Showing Average Weight of Muscle per Fish of Standard Length from 
 Estuaries : 
 
 
 Spey. 
 
 Dee. 
 
 Helms- 
 dale. 
 
 Average. 
 
 Limits of 
 Variation. 
 
 May and June, 
 
 6126 
 
 6345 
 
 6495 
 
 6326 
 
 54987230 
 
 July and August, 
 
 6768 
 
 6732 
 
 *8447 
 
 6901 
 
 62698447 
 
 Oct. and Nov., 
 
 6603 
 
 5982 
 
 - 
 
 6055 
 
 49377582 
 
 * Single fish. 
 
 In July and August there was a rise of 10-8 per cent, in the weight 
 of muscle as compared with May and June ; and a fall of 8'5 per cent, 
 in the October and November fish compared with the mean of the fish 
 from May to August.
 
 of the Salmon in Fresh Water. 
 
 G7 
 
 4. The weight of muscle in fish in the estuaries is greater than in fish 
 in the upper reaches, and this difference becomes more marked as the 
 season advances. 
 
 TABLE VI. 
 
 Showing Average Weight of Muscle per Fish of Standard Length in 
 Upper Waters: 
 
 
 Spey. 
 
 Dee. 
 
 Helms- 
 dale. 
 
 Average. 
 
 Limits of 
 Variation. 
 
 May and June 
 
 5566 
 
 5551 
 
 6535 
 
 5839 
 
 53586942 
 
 July and August 
 
 5555 
 
 6218 
 
 5997 
 
 5887 
 
 53226351 
 
 Oct. and Nov. 
 
 4555 
 
 4252 
 
 3974 
 
 4116 
 
 37124555 
 
 *Single fish. 
 
 If the average of the three rivers be taken the figures are as follows: 
 
 TABLE VII. 
 
 Shouting Aven*age Weight of Muscle per Fish of Standard Length: 
 
 
 Estuary. 
 
 Upper 
 Water. 
 
 Difference. 
 
 May and June 
 
 6326 
 
 5839 
 
 487 
 
 July and August 
 
 6901 
 
 5887 
 
 1014 
 
 October and November . 
 
 6055 
 
 4116 
 
 1939 
 
 Or, comparing the upper- water fish in October and November with the 
 upper-water fish earlier in the year, a loss of nearly 28 per cent, in 
 the weight of the muscle is found. 
 
 (c) Ovaries. 
 
 5. The weight of the ovaries per fish of standard length increases steadily 
 throughout the season both in the sea and in the river. These results 
 may be compared with those of Hoek and Miescher, and of the Scottish 
 Fishery Board (Fishery Reports 1895, Table p. 30). By these observers 
 the weight of the ovaries is given not as per fish of standard length, but as 
 percentage of the weight of the fish . Hoek's observations on salmon in the 
 Lower Rhine show an increase in the ovaries of from 0'5 per cent, in 
 March to 20 per cent, in November, while Miescher's investigations in 
 the Upper Rhine at Basel give an increase of from 0'75 per cent, in 
 March to 23 in November. 
 
 The investigations at the mouth of the Tweed give an increase from 
 0-75 per cent, in March to 17 per cent, in November: 
 
 [TABLE.
 
 68 Investigations on the Life-History 
 
 TABLE VIII. 
 
 Showing Average Weight of Ovaries per Fish of Standard Length ;- 
 
 
 Spey. 
 
 Dee. 
 
 Helnisdale. 
 
 
 Est'ry 
 
 Upper 
 
 Est'ry 
 
 Upper 
 
 Est'ry 
 
 Upper 
 
 May and June - 
 
 106 
 
 177 
 
 118 
 
 392 
 
 140 
 
 257 
 
 July and August 
 
 286 
 
 463 
 
 283 
 
 691 
 
 *204 
 
 482 
 
 October and November 
 
 1428 
 
 2890 
 
 1454 
 
 2083 
 
 
 
 2157 
 
 * Single Fish. 
 
 Or taking these together : 
 
 TABLE IX. 
 
 Showing Average Weight of Ovcvries per Fish of Standard Length: 
 
 May & June 
 July & Aug. 
 Oct. & Nov. 
 
 Estuary. 
 
 Limits of Variation 
 
 Upper. 
 
 Limits of Variation 
 
 121 
 
 284 
 1439 
 
 53175 
 109479 
 13101930 
 
 263 
 510 
 2230 
 
 104415 
 353691 
 
 18512888 
 
 This gives an increase from May to November of from 1 to 1 1 '9 in the 
 sea, or 1318 grms. per fish of standard length, and from 1 to 8*5 
 in the river, or 1967 grms. per fish of standard length. It will 
 thus be seen that although in the upper waters a greater amount of 
 material per fish of standard length is laid on by the ovaries, their rate 
 of growth, considering the weight with which they start in May, is quite 
 as great in the sea as in the river. 
 
 Throughout every part of the season there is a most marked difference 
 in the ovaries in the upper reaches of the river and at the mouth. 
 
 In May and June the ovaries of the fish in the upper reaches are 
 117 per cent, heavier than those at the mouth, while in October and 
 November they are 55 per cent, heavier. 
 
 (d) Length of Salmon. 
 
 6. The length of the fish coming to the mouth of the river increases 
 markedly in October and November, while the length of fish in the 
 upper reaches remains fairly constant throughout the season, and 
 corresponds to the length of fish at the mouths from May to August. 
 
 TABLE X. 
 
 Showing Average Length of Fish : 
 
 
 Estuary. 
 
 Upper Water. 
 
 May and June - 
 
 74 
 
 75 
 
 July and August 
 October and November 
 
 77 
 88 
 
 72 
 73
 
 of the Salmon in Freak Water. 69 
 
 In drawing conclusions from these figures, it must be remembered 
 that fish of from 8 to 10 Ibs. were asked for, but as the supply available 
 was limited, the size of the fish sent was not specially regarded by the 
 senders. Fortunately, the question has been elucidated by the investiga- 
 tions at Berwick-on-Tweed. The following Table shows the results 
 obtained from the examination of female salmon as given in the Fishery 
 Board Report for 1895, pp. 64 to 72. 
 
 TABLE XI. 
 
 Showing Average Length of Fish in Kstiiaries : 
 
 
 No. of Fish. 
 
 Length. 
 
 April 
 
 May - 
 
 29 
 43 
 
 77 
 77-1 
 
 June - 
 
 29 
 
 77-3 
 
 July - 
 
 33 
 
 77-3 
 
 August 
 
 30 
 
 81 
 
 September 
 
 18 
 
 84 
 
 October 
 
 37 
 
 89 
 
 November - 
 
 45 
 
 88-3 
 
 FEMALE FISII, 1895. 
 (a) Fish from B&rvnck-on-Tweed. 
 
 In seven of these the ovaries, liver, and muscle thick and thin were 
 weighed. The percentage results obtained agreed generally with those 
 obtained from fish caught in the various estuaries during 1896, but as 
 the weight of muscle per fish of standard length was not determined 
 it is unnecessary to give the results of these analyses. 
 
 (6) Fish from Montrose. 
 
 So far as I am aware, all the fish received from Montrose were 
 captured in the lower waters of the North Esk or in Montrose Bay. 
 They are therefore to be considered as estuary fish and compared with 
 the estuary fish of 1896. 
 
 Table XII. gives the length, weight, weight of muscle, and weight of 
 ovaries. 
 
 A comparison of this Table with Table 1. (p. 64) shows a close correspond- 
 ence, and bears out Conclusions 1 and 4. As regards the growth of the 
 ovaries, it is to be noted that in the North Esk fish in July the ovaries 
 were more developed than in the July and August fish of 1896, but that 
 their average development did not exceed the greatest development 
 observed in the 1896 fish. In the later months the North Esk fish have 
 a somewhat less average size of ovary than the 1896 fish. 
 
 [TABLE.
 
 70 
 
 Investigations on the Life-History 
 
 TABLE XII. 
 
 FEMALE SALMON, 1895. 
 
 
 Weight. 
 
 Muscle. 
 
 Ovaries. 
 
 Remarks. 
 
 No. 
 
 Date. 
 
 Lgth. 
 
 Actual 
 
 Per Fish 
 ofStnrd. 
 Length. 
 
 Actual 
 
 2590 
 1262 
 3630 
 
 Per 
 Fish of 
 Std. 
 Lgth. 
 
 Actual 
 
 PrFsh 
 
 of Std. 
 Lgth. 
 
 North Esk. 
 3rls. Montrose 
 Montrose Bay. 
 
 North Esk. 
 
 10 
 
 11 
 12 
 
 Average- - 
 
 23.7 
 
 76 
 61 
 
 78 
 
 4130 
 2055 
 5390 
 
 9410 
 9053 
 11359 
 
 9940 
 
 5899 
 5560 
 7671 
 6377 
 
 218 
 725 
 218 
 
 496 
 319 
 459 
 424 
 
 24 
 25 
 Average - - 
 
 3.9 
 
 81 
 90 
 
 5954 
 7704 
 
 11235 
 10568 
 10901 
 
 
 278 
 240 
 
 523 
 331 
 427 
 
 29 
 31 
 
 39 
 Average - - 
 
 26.10 
 28.10 
 12.12 
 
 76 
 94 
 91 
 
 4555 
 9300 
 7686 
 
 10376 
 11197 
 10203 
 10592 
 
 2680 
 5560 
 3740 
 
 6105 
 6694 
 4322 
 5707 
 
 317 
 995 
 1588 
 
 722 
 1199 
 2108 
 1343 
 
 MALE SALMON. 
 
 For the study of male fish the amount of material at our disposal was 
 unfortunately very limited. 
 
 TABLE XIII. 
 
 Showing the Length, Weight of Muscle, and Weight of 
 and per Fish of /Standard Length : 
 
 May and June 
 ESTUARIES. 
 
 , both Actual 
 
 
 
 
 Weight. 
 
 Muscle. 
 
 Testes. 
 
 No. 
 
 River. 
 
 Length. 
 
 
 
 
 
 
 
 Total. 
 
 Per Std. 
 Fish. 
 
 Total. 
 
 Per Std. 
 Fish. 
 
 Total. 
 
 Per Std. 
 Fish. 
 
 13 
 
 Spey . . 
 
 77 
 
 4090 
 
 8958 
 
 2670 
 
 5850 
 
 5 
 
 10-97 
 
 19 
 
 Annan . . 
 
 80 
 
 4435 
 
 8662 
 
 2870 
 
 5605 
 
 8 
 
 15-62 
 
 
 Averages . 
 
 78-5 
 
 4262 
 
 8810 
 
 2770 
 
 5727 
 
 6.5 
 
 13-3 
 
 UPPER WATER. 
 
 26 
 34 
 
 Helmsdale 
 Dee . . . 
 
 83 
 
 68 
 
 5557 
 2650 
 
 9737 
 
 8429 
 
 3544 
 1654 
 
 6209 
 5261 
 
 24 
 14 
 
 42-05 
 
 44-46 
 
 
 
 75-5 
 
 4103 
 
 9083 
 
 2599 
 
 5735 
 
 19 
 
 43-2 
 
 J idy and 
 ESTUARIES. 
 
 53 
 
 Annan . . 
 
 77 
 
 5290 
 
 11588 
 
 3564 
 
 7800 
 
 14 
 
 32-86 
 
 56 
 
 Spey . . 
 
 74 
 
 4480 
 
 11056 
 
 2810 
 
 6934 
 
 8 
 
 19-74 
 
 59 
 
 Spey . . 
 
 87 
 
 7010 
 
 10644 
 
 4604 
 
 6991 
 
 24 
 
 36-44 
 
 61 
 
 Annan . . 
 
 84 
 
 5650 
 
 9533 
 
 3230 
 
 5450 
 
 45 
 
 75-92 
 
 
 Averages . 
 
 80-5 
 
 5607 
 
 10705 
 
 3552 
 
 6794 
 
 23 
 
 41-2
 
 of the Salmon in Fresh Water. 
 
 TABLE XIIL- Continued. 
 
 July and August. 
 
 UPPER WATER. 
 
 7! 
 
 
 
 
 Weight. 
 
 Muscle. 
 
 Testes. 
 
 No. 
 
 River. 
 
 Lsngth. 
 
 
 
 
 
 
 
 Total. 
 
 Per Std. 
 Fish. 
 
 Tot,, I*"* 
 
 Total. I^Jtd. 
 
 38 
 
 
 Helmsdale 
 
 74 
 
 3870 
 
 9551 
 
 2454 
 
 5957 
 
 10 
 
 44-42 
 
 39 
 
 Dee. . . 
 
 77 
 
 3885 
 
 8510 
 
 2420 
 
 5301 
 
 44 
 
 96-38 
 
 54 
 
 Dee . . . 
 
 79 
 
 3880 
 
 7810 
 
 2314 
 
 4694 
 
 101 
 
 204-88 
 
 
 
 77 
 
 3878 
 
 8623 
 
 2396 
 
 5317 
 
 52 
 
 115-2 
 
 October and November. 
 ESTUARIES. 
 
 71 
 75 
 
 Dee. 
 Dee . . . 
 
 Averages . 
 
 108 
 68 
 
 12,760 
 2890 
 
 10129 
 9192 
 
 7610 
 
 1660 
 
 6041 
 
 5280 
 
 270 
 96 
 
 214-33 
 305-34 
 
 88 
 
 7285 
 
 9660 
 
 4635 
 
 5660 
 
 183 
 
 260 
 
 UPPER WATER. 
 
 68 
 
 Dee. . . 
 
 74 
 
 3280 
 
 8094 
 
 1712 
 
 4225 
 
 109 
 
 269- 
 
 (a) Weight. 
 
 1 . The weight per fish of standard length increases in the salmon 
 coming to the mouths of the rivers to August. 
 
 TABLE XIV. 
 
 Showing Average Weight per Fish of Standard Lent 
 
 Estuaries :- 
 
 
 Weight per Fish 
 of Sbd. Length. 
 
 Limits of 
 Variation. 
 
 May and June, 
 
 8810 
 
 8662 8958 
 
 July and August, - 
 
 10705 
 
 953311588 
 
 October and November, - 
 
 9660 
 
 919210129 
 
 2. The difference between the weight of the fish at the mouth and in 
 the upper waters of the rivers is practically nil in May and June, but 
 as the season advances the weight of the fish in the upper reaches 
 becomes less than that of fish in the lower reaches. 
 
 In May and June there is a difference of only 3 per cent. In July 
 and August the estuary fish are 19 per cent heavier than the upper- 
 water fish, and in October and November 16 per cent, heavier.
 
 72 Investigations on the Life- Hi story 
 
 TABLE XV. 
 
 Showing Average Weight per Fish of Standard Length in Upper Waters: 
 
 
 Weight per Fish 
 of Standard 
 Length. 
 
 Limits of 
 Variation. 
 
 May and June, 
 
 9083 
 
 84^09737 
 
 July and August, 
 
 8623 
 
 78109551 
 
 October and November, 
 
 8094 
 
 8194 
 
 (b) Jfusde. 
 
 The weight of muscle in fish coming to the estuaries is greatest in 
 July and August and least in October and November. In May and 
 June the weight of muscle is the same in fish in the upper waters as in 
 fish in the estuaries, but in July and August it is 22 per cent, less and 
 in October and November 25 per cent. less. 
 
 TABLE XVI. 
 
 Showing Average Weight of Muscle per Fish of Standard Length: 
 
 
 Estuaries. 
 
 Upper Waters. 
 
 May^and June, 
 
 5727 
 
 5735 
 
 July and August, - 
 
 6794 
 
 5317 
 
 October and November, - 
 
 5660 
 
 4225 
 
 w 
 
 The weight of the testes increases in fish in the estuary and in the 
 upper waters throughout the season, and the increase is as marked in fish 
 inJJie estuaries as in fish in the upper waters. 
 
 TABLE XVII. 
 
 Show-ing Average Weight of Testes per Fish of Standard Length : 
 
 
 Estuaries. 
 
 Upper Waters, 
 
 May and June, 
 
 13-3 
 
 43-2 
 
 July and August, - 
 
 41-2 
 
 115-2 
 
 October and November, - 
 
 260-0 
 
 269-0
 
 of the Salmon in fresh Water. 73 
 
 KELTS. 
 
 It is a matter of no little interest to trace the changes which take 
 place in the salmon between the time of spawning and their return to 
 the sea. 
 
 It is supposed by some that kelts feed voraciously. Of the two 
 salmon captured at Basel in which Miescher Ruesch found traces of 
 food, both were kelts. 
 
 The evidence adduced by Dr. Gulland shows that the lining membrane 
 of the stomach is regenerated in the kelt stage, while Dr. Gillespie's 
 observations show that the digestive power is greater in kelts than in 
 tmspawned salmon. In the kelts examined by us food was never found 
 in the stomach, but, in nearly all, the gall-bladder contained a greater or 
 less quantity of bile. 
 
 Miescher Ruesch describes the changes in the salmon after spawning 
 as follows : 
 
 After a vivid description of the characters of the fish on the spawning 
 beds, he says (p. 215): 
 
 " How altogether different is the picture if we have the opportunity 
 to see the animal ten days, or, better, two weeks, after spawning. The 
 skin is again blueish, shining and clear, the ulcers cicatrized and healing, 
 the flesh transparent and free of oil granules. The heart fibres also 
 participate in the regenerative change; in the intestine is no trace of food. 
 On the other hand, the ovary contains sometimes more, sometimes fewer 
 eggs, which are embedded in a serous or somewhat purulent effusion of 
 the follicular membrane, and are evidently shrinking and being absorbed. 
 They are thus a sort of nourishment, a provision (Zehrgeld) for 
 the return journey. But I ascribe the chief importance to the pale, 
 shrunken, and folded follicular membrane. The collateral vessels of the 
 ovary are closed through vascular contraction. The salmon is like a 
 patient who has had a leg amputated after the application of an 
 Esmarch's bandage. Its blood courses in a narrow circulation, thus 
 with higher pressure, and supplies a less amount of oxygen-requiring 
 matter than formerly. The circulation is again sufficient for its task, 
 
 and the trunk muscle-; becomes normal The little nutrient 
 
 matter coming from the ovary greatly helps the reconvalescence of the 
 muscle." 
 
 In the spring of 1897, 22 kelts were received from the mouth of the 
 Spey between the 17th March and the 21st May, and other three kelts 
 were procured in 1895-96. 
 
 The weight of muscle, ovaries, etc., was determined in eleven of these, 
 and a detailed analysis was made of four. 
 
 Table XVIII. gives the length, weight, weight per nsh of standard 
 length, weight of musculature total and per fish of standard length, 
 and weight of ovaries total and per fish of standard length. The length 
 is in centimetres and the weight in grammes : 
 
 [TABLK.
 
 74 
 
 In ''Vitiations on the Life-History 
 
 TABLE XVIII. 
 KELTS. 
 
 W-. 
 
 I 1-, t ,. 
 
 
 Weight. 
 
 Muscle. 
 
 Ovaries. 
 
 
 .HO. 
 
 Uate. 
 
 Length. 
 
 Total 
 
 Per Std. 
 Fish. 
 
 Total 
 
 Per Std. 
 Fish. 
 
 Total 
 
 Per Std. 
 Fish. 
 
 
 14 
 
 1895. 
 July 23 
 
 83 
 
 3,995 
 
 6,986 
 
 2,400 
 
 4,196 
 
 42-5 
 
 74 
 
 N. Esk. 
 
 
 1896. 
 
 
 
 
 
 
 
 
 
 8 
 
 March 17 
 
 66 
 
 2.458 
 
 _ 
 
 1,512 
 
 _ 
 
 11 
 
 
 
 N. Esk. 
 
 9 
 
 17 
 
 65 
 
 2',280 
 
 
 
 1,222 
 
 
 
 14 
 
 
 
 N. Esk. 
 
 80 
 81 
 82 
 
 1897. 
 March 17 
 18 
 
 18 
 
 87 
 93 
 92 
 
 5,434 
 6,847 
 6,235 
 
 8,245 
 8,518 
 8,004 
 
 3,070 
 4,000 
 3,500 
 
 4,658 
 4,974 
 4,492 
 
 29 
 52 
 65 
 
 44 
 64 
 83 
 
 Spey. 
 
 83 
 
 18 
 
 89 
 
 4,800 
 
 6,866 
 
 2,480 
 
 3,548 
 
 42 
 
 60 
 
 
 
 84 
 85 
 
 April 1 
 5 
 
 93 
 94 
 
 6,485 
 6,455 
 
 8.064 
 7,771 
 
 3,916 
 3,610 
 
 4,807 
 4,346 
 
 38 
 40 
 
 47 
 
 48 
 
 
 
 86 
 
 8 
 
 94 
 
 6^95 
 
 8,252 
 
 3,730 
 
 4,490 
 
 54 
 
 65 
 
 
 
 87 
 
 15 
 
 91 
 
 6,280 
 
 8,339 
 
 
 
 
 
 
 
 
 
 
 
 88 
 
 15 
 
 96 
 
 6,110 
 
 7,000 
 
 
 
 
 
 
 
 
 
 
 
 89- 
 
 15 
 
 65 
 
 1,877 
 
 6,829 
 
 
 
 
 
 
 
 
 
 
 
 90 
 
 21 
 
 91 
 
 5,975 
 
 7,934 
 
 
 
 
 
 
 
 
 
 
 
 91 
 
 21 
 
 89 
 
 5,510 
 
 7,882 
 
 
 
 
 
 
 
 
 
 
 
 92 
 
 27 
 
 91 
 
 5,525 
 
 7,311 
 
 3,120 
 
 4,140 
 
 31 
 
 41 
 
 
 
 93 
 
 30 
 
 98 
 
 6,955 
 
 7,389 
 
 _ 
 
 
 
 
 
 
 
 
 
 94 
 
 My 5 
 
 92 
 
 6,080 
 
 7,809 
 
 
 
 
 
 
 
 
 
 
 
 95 
 
 5 
 
 90 
 
 5.735 
 
 7,867 
 
 
 
 
 
 
 
 
 
 
 
 96 
 
 
 67 
 
 2,365 
 
 7,865 
 
 
 
 
 
 . 
 
 - 
 
 
 
 97 
 
 6 
 
 85 
 
 5,060 
 
 8,239 
 
 
 
 
 
 
 
 
 
 
 
 98 
 
 10 
 
 90 
 
 5,085 
 
 6,975 
 
 
 
 
 
 
 
 
 
 
 
 99 
 
 12 
 
 69 
 
 2,282 
 
 6,943 
 
 
 
 _ 
 
 
 
 
 
 
 
 100 14 
 
 91 
 
 6,035 
 
 8,008 
 
 
 
 
 
 
 
 
 
 
 
 101 21 
 
 85 
 
 4,867 
 
 7,925 
 
 
 
 
 
 
 
 
 
 
 | Average 
 
 83-8 
 
 5091 
 
 7,755 
 
 2,960 
 
 4,487 
 
 38 
 
 56 
 
 
 
 From the length of the fish it is manifest that most of these are 
 kelts of the late-coming fish October and November salmon. 
 
 Whether the smaller fish which come from the sea earlier in the year 
 descend at an earlier date is not shown by these results. 
 
 The table bhows : 
 
 ( 1 ) That, as might be expected, the kelts are lighter per fish of standard 
 length than the unspawned fish. 
 
 (2) The amount of muscle is rather greater than in the unspawned 
 fish. This is of interest in connection with Miescher Ruesch's descrip- 
 tion of the possible regeneration of the muscle from the ova retained in 
 the peritoneal cavity. 
 
 (3) The weight of the ovaries is smaller than in the fish coming to 
 the rivers in May and June. It should be mentioned that in all these 
 kelts a considerable number of unshed ripe ova were always found in 
 the abdominal cavity. 
 
 As compared with winter salmon 72 and 79 (Table I., p. 65), the 
 weight of ovaries in the kelt is not appreciably smaller. The average 
 weight of ovaries in 72 and 79 was 81 grms. per fish of standard 
 length. The average weight in the kelts was 58 grms. ; but while the 
 ovaries of 79 were only GG grms. per fish of standard length, kelt 82 had 
 ovaries of 83 grms. 
 
 GENERAL CONCLUSIONS FROM THESE RESULTS. 
 These figures throw important light upon several questions : 
 1st. They confirm the conclusions arrived at by Mr. Archer in his
 
 of the Salmon in fresh Water. 75 
 
 Report of 1895, that fish continue to feed in the sea at least till the end 
 of August. The marked diminution in the amount of muscle in fish 
 reaching the estuaries in October and November would seem to show 
 that the supply of food is insufficient to yield the material necessary 
 for the rapidly growing genital glands, and that therefore the solids of 
 the muscle have to be drawn upon, or, at least, that accumulation of material 
 in the muscles is prevented. The steady increase in weight per fish of 
 standard length throughout the season seems to indicate that they con- 
 tinue to feed even after August and (September, though, as will be 
 shown later (p. 86), the flesh contains about 5 per cent, more water 
 in October and November than in July and August, while the increase 
 of weight is only 3*7 per cent. 
 
 2nd. The fall in the amount of muscle from the early to the late put 
 of the season in fish in the upper reaches supports the conclusions 
 arrived at by Meischer Ruesch, and by Drs. Gulland and Gillespie, 
 that the salmon does not feed in fresh water. 
 
 3rd. Light is thrown on the question of whether fish entering the 
 river early in the year go straight up and occupy the upper reaches, 
 leaving the lower parts to be occupied by the later-coming fish. 
 
 The following facts bear specially upon this : 
 
 (1) The length of the fish coming to the mouth of the rivers is practi- 
 cally the same from May to August (pp. 68 and 69). But in October and 
 November a markedly larger class of fish appears in the estuaries. In 
 the upper reaches, however, the size of the fish remains constant till 
 October. This would seem to show that from early spring to August 
 the fish pi-ess upwards, but that after this the later arrivals occupy the 
 lower reaches of the river. 
 
 (2) The fact that the weight per fish of standard length steadily rises 
 in the estuaries throughout the season, and rises in the upper waters also 
 until July and August, seems to show the passage of fish to the upper 
 reaches during these months. But there is no increase of the weight of 
 the upper-water fish in October and November corresponding to the 
 increase in weight of those at the estuaries. This supports the view that 
 the early-coming fish pass on to the upper reaches. 
 
 (o) The weight of the musculature increases in fish coming to the 
 mouth of the rivers from May to Atigust. There is also a slighter 
 increase in fish in the upper reaches, due probably to the immigration 
 of these more muscular fish from the mouth. But in October and 
 November, while the estuary fish show only a slightly less developed 
 musculature, the fish in the upper reaches show a very marked diminu- 
 tion, indicating that immigration from below has practically stopped. 
 
 These conclusions are further supported by the evidence adduced in a 
 footnote of the Appendices of the Twelfth Annual Report to the Fishery 
 Board, 1893, pp. 55 and 56 : 
 
 " If fish ascended the rivers in the spring of the year only to rid them- 
 selves of sea-lice, sis some consider, they might be expected to ascend 
 only a short distance ; whereas, it seems, on the contrary, that in some 
 rivers, at any rate, they press up immediately to the head waters. 
 Thus, in the Forth District, it is said to be the floods in January and 
 February that induce the fish to ascend to Lochs Venriacher and Achray. 
 In the 'Tay District, the fishing is best in the Loch Tay in the early 
 months of the year ; and I am informed by a gentleman well acquainted 
 with the fishings at the foot of the falls of Tummel, that it is the M:irch 
 floods that give a successful season in those waters, whereas the autumn 
 fish do not ascend so far. The superintendent of the river Dee, in
 
 76 Investigations on the Life-History 
 
 Aberdeenshire, informs me that the spring fish in that river press up 
 stream into the tributaries, some 15 to 20 miles above Braemar ; whereas 
 the autumn fish, which collect in the greatest numbers between 
 Banchory and Ballater, are seldom found above Braemar. He distin- 
 guishes between spring and autumn fish from the fact that fish taken 
 ascending the river in the spring are, as a rule, small fish, whereas those 
 taken in the autumn are considerably larger. Small fish, corresponding 
 in size to the spring fish and much discoloured, showing they had been 
 in the fi-esh water a long time, are found in the upper part of the river, 
 and are the first to spawn ; whereas the fish in the lower part of the 
 river resemble, in size, those caught during the autumn, and present the 
 appearance of having more recently left the sea. 
 
 " In the district of the river Ness, the fish run straight through the 
 river Ness and Loch Ness into the river Garry. The river Garry flows 
 into the upper end of Loch Ness. Indeed, it is said that, although the 
 Oick and Garry fish must pass up the Ness, scarcely any settle there, no 
 fish being taken in the Ness by the fly before July. The same is said 
 of the Orchy on the West Coast. The Orchy flows into Loch Awe, 
 which is connected with the sea by the river Awe. The Awe is a late 
 river, the heaviest salmon being got in the autumn, while the Orchy 
 below the falls is best in the spring. The spring fish are said, as a rule, 
 to come right up to the long, deep, rocky pool below the falls. In the 
 river Severn in England, Mr. Willis Bund, in his book Sedition Problems, 
 says that there is a spring run of small salmon, weighing from 81bs. to 
 1 51bs., in February and March. These are very strong active fish, and 
 press up the river at once, those getting to the top forming the early 
 spawners. These instances are sufficient to show that in some rivers, at 
 any rate, clean fish, having their roe very slightly developed, ascend at, 
 once to the head waters of the river. 
 
 " It will be observed, also, that the observations of Mr. Willis Bund on 
 the Severn, and the superintendent of the water bailiffs on the Dee, tend 
 to show that the spring fish are the early spawners, and form the 
 breeding stock in the head waters of the rivers. The observations of 
 Mr. Ffennel, one of the commissioners appointed under the Salmon 
 Fisheries (Scotland) Act of 1862, correspond with those of Mr. Willis 
 Bund and the superintendent of the Dee. In his evidence before the 
 Select Committee of the House of Lords in 1860, he said that tin- 
 salmon which entered the rivers in November, December, January, 
 February, and March, spawned in the following October. He said that 
 in the river he had lived upon, the Suir, he had watched salmon from 
 childhood ; in February new fish came up plentifully, the water got very 
 low and clear, and they could see them in the pools through the summer. 
 He had, therefore, no doubt that salmon would live and thrive for a 
 whole twelve months in fresh water. He further stated that these fish, 
 although discoloured, remained very fat and exceedingly good to eat up 
 till midsummer. 
 
 " At Sand in Norway, where I watched the habits of salmon for some 
 years, the early fish having high crests and slight development of roe, 
 <sime into the river in June. These fish, as soon as they could pass the 
 first fall, ran right up to the second, whereas the lower pools did not 
 contain fish in any numbers until late on in the autumn." 
 
 4th. It has been sometimes suggested that the fish which ascend the 
 rivers early in spring do not remain there throughout the season, but 
 that they may again descend to the sea to feed, and again ascend the 
 river to spawn later in the season. That salmon may and do move up 
 and down the rivers during the summer and autumn there can be no
 
 of the Salmon in Fresh Water. 
 
 doubt, but, so far as I am aware, there is absolutely no evidence that once 
 having fairly pntered the river they ever return to the sea in any con- 
 siderable number. Were this the case, did a constant to-and-fro migra- 
 tion from sea to river and river to sea occur, we should not expect to find 
 any marked difference between the fish in the estuaries and the fish in 
 the upper reaches. But our figures show that as regards weight, as 
 regards weight of muscle, and as regards weight of ovaries and testes, 
 there is a mai-ked difference, becoming more accentuated as the season 
 advances, between fish in estuary and fish in the upper waters. And 
 the more carefully these figures are analysed the more forcibly do they 
 tell against such a to-and-fro movement. 
 
 In considering the total weight of the salmon, it might be thought 
 that the very marked overlap between the heaviest fish in the upper 
 reaches and the lightest fish in the estuary favoured this view. 
 
 Weight per Standard Fish. 
 
 
 Estuary. 
 Lightest. 
 
 Upper Reaches. 
 Heaviest. 
 
 Overlap. 
 
 May and June - 
 
 8,714 
 
 10,055 
 
 1,341 
 
 July and Aug. - 
 
 9,610 
 
 10,370 
 
 760 
 
 Oct. and Nov. 
 
 10,270 
 
 11,130 
 
 360 
 
 Analyses of the weights of the musculature and of the ovaries shows 
 that no significance can be given to these figures. ^ 1 
 
 In the first place the very small overlap between the smallest ovaries 
 of the upper-water fish and the largest ovaries of the estuary fish 
 opposes the idea of there being any free exchange between these 
 situations. 
 
 Weight of Ovaries per Standard Fish. 
 
 
 
 Estuary. 
 Heaviest. 
 
 Upper Reaches. 
 Lightest. 
 
 Overlap. 
 
 May and June - 
 
 183 
 
 175 
 
 72 
 
 July and Aug. - 
 
 353 
 
 479 
 
 126 
 
 Oct. and Nov. 
 
 1,930 
 
 1,351 
 
 None. 
 
 But a comparison of the musculature is the most convincing. In May 
 and June while the fish are running, when no time has been allowed for 
 any difference to develop between the fish leaving the sea and those in 
 the upper reaches, the overlap between the largest musculature of the 
 upper-water fish and the smallest musculature of the estuary fish is 
 fairly marked. By July and August the overlap has practically ceased 
 to exist, and by October and November the heaviest musculature of the 
 upper-water fish is less than the smallest musculature of the estuary 
 fish.
 
 78 
 
 Investigations on the Life- History 
 Weight of Nusde per Standard Fish. 
 
 
 Estuary. 
 Smallest. 
 
 Upper Reaches. 
 Largest. 
 
 Overlap. 
 
 May and June - 
 
 5,498 
 
 6,940 
 
 + 1,442 
 
 July and Aug. - 
 
 6,269 
 
 6,350 
 
 + 81 
 
 Oct. and Nov. - 
 
 4,937 
 
 4,550 
 
 None 
 
 Such conditions would be impossible were there a free to-and-fro 
 migration. 
 
 5th. The close correspondence between the fish from the Helmsdale, 
 Spey, and Dee appears to indicate that these may be regarded practically 
 as one river. The experiments on marking fish at present being con- 
 ducted by Mr. Archer, so far as they go, support this idea. 

 
 of the Salmon in Fresh Water. 
 
 CHEMICAL CHANGES IN THE SALMON IN FEESH 
 WATER. 
 
 PRELIMINARY CONSIDERATIONS. 
 
 BY D. NOEL PATON, M.D., F.R.C.P. ED. 
 
 It has been already shown that the salmon leaving its marine feeding 
 ground ascends the river and remains until the spawning time, often for 
 several months, without any supply of nourishment from without. 
 
 During this period it must thus subsist upon the store of material in 
 its body brought from the sea. 
 
 Hence a comparison of the condition of the salmon in the upper 
 reaches and in the estuary of the river at different periods will make 
 manifest the progress of the changes which go on in the fish during its 
 prolonged fast, and will explain how the material for the growth of the 
 genitalia and for the muscular energy required in the ascent of the 
 stream is obtained. 
 
 The following sections deal with these matters : 
 
 The question has been already investigated and discussed by Miescher 
 tluesch (loc. cit.), and before proceeding to give the results of the 
 present enquiry it is necessary to carefully consider his important 
 work. 
 
 1. His investigations were practically confined to fish obtained in the 
 upper waters of a long river at the Basel-Laufenberg fisheries, about 
 500 miles from the mouth of the Rhine. 
 
 2. His observations extended over three seasons, 1877 to 1880. From 
 the measurement and weighing of 470 salmon of from 840 to 917cm. in 
 length from May to November, he concludes that on an average the fish 
 loses about 6 per cent, of its weight from May 22nd to October 12th. 
 
 3. From observations on 39 salmon he states that during this period 
 the ovaries increase from 1*1 percent, of the body weight to about 23 
 per cent. 
 
 4. Analyses of the muscle in 15 salmon show that in the earlier part 
 of the year in July and August there is about 17-5 per cent, of 
 albumin (pro^eids), while later in November and December there 
 is only 13 per cent. He concludes that this loss of albumin alone from 
 the lateral trunk muscles is sufficient to cover four-fifths of the weight 
 of the full-grown ovaries. 
 
 5. From the difference between the weight of the total solids and the 
 albumin he calculates the amount of fat in the muscle, and shows that in 
 August it is about 5 per cent, and in November about 2'2 per cent. 
 
 6. To study the changes of material more accurately two salmon were 
 taken, one on the 7th and one on the 4th of August 1578, one an
 
 80 Investigations on the Life-History 
 
 average fish, the other an exceptionally thin fish, and in these fish the 
 various organs were carefully weighed and analysed. 
 
 From his previous average tables he calculates what the weight of 
 muscle, ovaries, etc., of these fish would have been on November 1st, 
 and what would have been the proportion of albumin and fats in these 
 organs. Then balancing the condition in August with the supposed 
 condition in November he concludes that the amount of albumin and 
 fat lost from the muscle is more than sufficient to biiild up the ripe 
 ovaries. 
 
 A number of other points of interest are also considered in the 
 enquiry, such as the transference of phosphorus from muscle to ovaries ; 
 the nature of the phosphorus compounds in each, and the nature of the 
 ovarian fluid. Some of these points will have to be dealt with in a later 
 part of this Report, some of them are of merely incidental interest and 
 need not be considered. 
 
 A careful consideration of Miescher's work shows that it leaves 
 untouched several questions of interest, and that the conclusions arrived 
 at are hardly warranted by the evidence produced. 
 
 In the first place it -leaves unconsidered the changes which the fish 
 undergo in passing from the sea up the river, and, therefore, does not 
 deal with the question of how much of the stored material in the fish 
 goes to the formation of the genitalia and how much is used as a 
 source of energy. 
 
 In the second place, in order to arrive at his conclusions, he 
 assumes that from August to November no fresh fish are coming to the 
 Basel water from the sea, since if this were the case his average results 
 could not be applied to the fish analysed. He argues at length against 
 the possibility of such an immigration of lower-water fish on the ground 
 that, if they came, there must be two classes of fish in the upper waters, 
 one poor in material, consisting of the fish which came up in spring, and 
 one richer in material, consisting of the fish which continued to feed in 
 the sea and came up with their genitalia more developed and with a 
 greater supply of nourishment in the muscle. According to Miescher 
 such two classes do not exist. It is, however, possible that the wide 
 divergence in the weights of individual fish noted by him as much as 
 20 or 30 per cent. may be explained by the arrival of these better 
 nourished fish. The observations recorded on p. 75 of this paper show 
 pretty clearly that in the shorter Scottish rivers, fish leaving the sea in 
 August do pass to the upper reaches. Again, in this argument he makes 
 the assumption, which he does not attempt to prove, that fish continue 
 to feed in the sea all through the autumn. 
 
 The conclusions which Miescher bases upon his analyses are so far- 
 reaching and important that they must be considered with critical care. 
 It seems hardly justifiable to base such conclusions upon so limited a 
 number of observations. Still less is it safe to assume that any two 
 particular cases will accord strictly with the average results. It must 
 be remembered that the detailed examination of only two fish is recorded. 
 So far as the analyses are concerned it may safely be concluded that 
 in the hands of so able a chemist these were properly carried out. 
 Two points, however, require to be pointed out. First, that the fats 
 were not directly determined, but that the difference between the total 
 solids and the albumin was taken to represent the fats. Second, for 
 the analyses of the muscle he says (p. 179) " An einer Reihe von Juli 
 und Augustsalmen wurde desshalb, immer von desselben Stelle genom- 
 men, der Eiweissgehalt des grossen Seitenrumpfmuskels bestimmt." 
 Apparently no cognisance was taken of the marked difference between 
 the trunk muscle generally the " thick " of the fish and the belly
 
 of t/ie Salmon in Finish Water. 81 
 
 muscle or " thin." From an analysis of one piece of muscle the 
 composition of the whole was calculated. He gives no analyses of the 
 ovaries, and says that he does not possess a sufficient number of com- 
 pleted analyses of the albumin of these structures, and he adopts 30 per 
 cent, as probably too high an amount. 
 
 It was for these reasons that a re-investigation and amplification of 
 Miescher's work appeared desirable, especially as his results have been 
 generally accepted and have been made the basis of very general con- 
 clusions in regard to the metabolic processes in starvation. 
 
 In approaching the subject we had the advantage of a supply of fish 
 from the mouth and upper waters of the rivers at the same periods, and 
 whole fish were placed at our disposal, so that the weight of the muscle, 
 ovaries and other structures could lie directly determined in each ease, 
 and complete analyses undertaken. 
 
 METHOD OF COMPARISON. 
 
 To compare the salmon of different sizes analysed during the enquiry, 
 all weighings of organs and of constituents of organs were expressed in 
 terms of fish of standard length 100 cm. (See page 6.) 
 
 It has been already shown that there is no essential difference 
 between the salmon from the Helmsdale, Spey, and Dee, and that at all 
 seasons they are practically in the same condition. Hence salmon from 
 the different rivers were considered as comparable with one another. 
 
 Instead of following Miescher's method of determining the nature of 
 the exchanges between muscle and ovaries, the following procedure was 
 adopted : 
 
 An average of the weighings and analyses of the different organs of 
 the fish from the estuaries and from the upper reaches of the rivers in 
 the three periods 
 
 May and June, 
 July and August, 
 October and November 
 
 were prepared, and from the differences between these, conclusions were 
 drawn as to the nature and extent of the change. 
 
 Since it is impossible to know whether the fish captured in the upper 
 waters in May and June had left the sea during these months, and had 
 not, in part at least, come up earlier in the year, no definite conclusions 
 are drawn from a comparison of the fish from these two situations 
 during this period. 
 
 On page 75 clear evidence has been advanced that the fish which run 
 in July and August pass up and mingle with the earlier run fish. It 
 therefore seemed justifiable to compare the upper-water fish of July and 
 August with the fish taken in the estuaries from May to August. 
 
 It has also been shown (page 75) that the fish which leave the sea 
 in October and November already full of more or less ripe spawn do 
 not immediately pass up to the upper reaches, but probably remain and 
 spawn in the lower part of the river. Hence the upper-water fish of 
 October and November have to be compared with the fish leaving the 
 sea in the earlier part of the year, from May to August, or with the 
 fish already in the upper water in July and August. 
 
 The following table shows this system of comparison : 
 
 Upper Water. Lower Water. 
 
 July and August Fish compared with May to August Fish. 
 October and November Fish May to August Fish.
 
 82 Investigations on the Life-History 
 
 SALMON ANALYSED. 
 
 Of the 55 female fish received during 1896, 36 were analysed. The.se 
 ^ire grouped as follows : 
 
 TABLE I. 
 
 May and June, 
 
 ESTUAKY FISH. 
 
 UPPER- WATER FISH. 
 
 Fish 
 Received. 
 
 Fish 
 Analysed. 
 
 Fish 
 Received. 
 
 Fish 
 Analysed. 
 
 14 
 
 7 
 
 7 
 
 6 
 
 July and August, 
 
 13 
 
 6 
 
 6 
 
 5 
 
 October & November, 
 
 7 
 
 5 
 
 8 
 
 7 
 
 Classified according to the rivers from which they were received : 
 TABLE II. 
 
 J uly and August, \ 
 
 October and 
 
 
 Helmsdale. 
 
 Spey. 
 
 Dee. 
 
 Mouth, 
 
 2 
 
 2 
 
 3 
 
 Upper, 
 
 2 
 
 
 
 1 
 
 Mouth, 
 
 1 
 
 2 
 
 3 
 
 Upper, 
 
 3 
 
 n 
 
 1 
 
 Mouth, 
 
 1 
 
 1 
 
 3 
 
 Upper, 
 
 5 
 
 
 
 2 
 
 Seven salmon received from Montrose in 1895 were also analysed. 
 Of the 14 male fish received in 1896, 6 from the estuaries and 6 from 
 the upper reaches of the rivers were analysed.
 
 of tJie /Salmon in Fresh Water. 
 
 83 
 
 7. THE CHANGES IN SOLIDS AND WATER OF MUSCLES, 
 AND GENITALIA OF THE SALMON IN FRESH WATER. 
 
 BY D. NOEL PATON, M.D., F.R.C.P.Ec. 
 
 In investigating the chemical changes in the tissues throughout the 
 season, we may begin by the consideration of the total solids of the 
 muscles and genitalia in fish from different stations throughout the 
 season. 
 
 METHOD. 
 
 The total solids were determined as follows : 
 
 The fat was extracted from the tissue in the manner afterwards to be 
 considered (p. 93). The residue was then dried at 110 C. and weighed. 
 To this the weight of the fat was added to give the total solids. 
 
 FEMALE SALMON, 1896. 
 
 Table I. gives the per cent, of solids in the thick and thin of 
 muscle, the solids calculated per fish of standard length, the per cent, of 
 solids and the solids per fish of standard length in the ovaries. 
 
 TABLE I. 
 
 ESTUARY FISH. 
 /. May and June. 
 
 No. 
 16 
 
 River. 
 Dee . 
 
 
 MUSCLE. 
 
 OVARIES. 
 
 Per Cent. 
 
 Total per 
 Fish of 
 Standard 
 Length. 
 
 Per Cent. 
 
 Total per 
 Fish of 
 Standard 
 Length. 
 
 31 
 
 Thick. 
 
 Thin. 
 
 34-3 
 
 387 
 
 2110 
 
 33-3 
 
 20 
 
 Helmsdale 
 
 
 33-7 
 
 38-3 i 2340 i 36-7 
 
 | I 
 
 52 
 
 25 
 
 Helmsdale 
 
 
 31-2 
 
 35-9 , 2130 
 
 34-5 
 
 59 
 
 27 
 15 
 
 Dee . 
 Spoy. 
 
 
 33-9 
 
 42-1 
 
 2250 
 
 35-6 
 
 52 
 
 Average, 
 
 33-2 
 
 38-7 
 
 2210 
 
 35-0 
 
 47-3 
 
 27-4 
 
 29-1 
 
 1660 
 
 33-7 
 
 36 
 
 17 
 
 Spey. . 
 
 
 31-7 
 
 33-9 
 
 1760 
 
 30-8 
 
 26 
 
 29 
 
 Dee . 
 
 Average of 
 
 
 29-4 
 29-5 
 
 35-6 
 
 1720 
 
 27-8 
 
 41 
 34 
 
 Average, 
 
 32-8 
 
 1710 
 
 29-7 
 
 two sets, 
 
 31-6 
 
 36-2 
 
 1990 
 
 32-9 
 
 42-4
 
 on the Li 
 TABLE I. Contimied. 
 II. July and August. 
 
 No. 
 
 River. 
 
 Dee . 
 Dee . 
 
 Spey. 
 Spey. 
 Dee . 
 
 
 
 MUSCLE. 
 
 OVARIES. 
 
 Per Cent, 
 
 Total per 
 Fish of 
 Standard 
 Length. 
 
 Per Cent. 
 
 Total per 
 Fish of 
 Standard 
 Length. 
 
 Thick. 
 
 Thin. 
 
 
 
 33-0 39-0 
 
 2230 36-2 
 
 96 
 
 
 
 32-1 37-0 
 
 2320 30-6 
 
 33 
 
 
 
 33-9 37-2 
 
 2170 32-0 
 
 49 
 
 
 
 32-5 
 
 34-3 
 
 2300 
 
 34-0 
 
 66 
 
 
 Average, 
 
 33-3 
 
 37-1 
 
 2360 
 
 39-2 
 
 116 
 
 32-9 
 
 36-1 ' 
 
 2270 
 
 34-4 
 
 72 
 
 ///. October and November 
 
 Spey 
 Dee . 
 Dee . 
 
 Dee . 
 Helmsdale 
 
 . 
 
 27-7 
 
 29-2 j 2040 
 
 38-1 
 
 593 
 
 
 27-8 
 
 35-7 1750 
 
 38-9 i 618 
 
 
 22-9 
 
 29-2 
 
 1470 
 
 39-7 
 
 514 
 
 Average. 
 
 26-1 
 
 31-3 
 
 1750 
 
 38-7 
 
 545 
 
 
 35-9 
 
 34-4 
 
 2414 
 
 28-7 ! 28-4 
 
 
 35-2 
 
 33-1 
 
 2549 
 
 28-4 17-9 
 
 Average, 
 
 35-5 
 
 33-7 
 
 2481 
 
 28-5 23-1 
 
 UPPER- WATEU FISH. 
 I. May and June. 
 
 a 
 
 Spey 
 
 
 21 
 
 Helmsdale 
 
 31 
 
 Spey 
 
 
 32 
 
 Dee . 
 
 
 11 
 
 Spey 
 
 
 30-9 
 
 34-5 
 
 1760 
 
 35-4 
 
 47 
 
 31-8 
 
 35-3 
 
 2000 
 
 35-2 
 
 77 
 
 28-6 
 
 30-8 
 
 1880 
 
 38-2 
 
 108 
 
 28-1 
 
 30-1 
 
 1520 
 
 36-2 
 
 150 
 
 29-8 
 
 32-7 
 
 1710 
 
 36-3 
 
 95-5 
 
 21-1 
 
 21.8 
 
 1200 
 
 28-8 
 
 46
 
 42 ; 
 
 43 % j 
 49l 
 
 of the tialmon in Fresh Water. 
 TABLE I. Continued. 
 II. July and August. 
 
 MUSCLE. 
 
 Spey 
 Spey 
 
 Helmsdale 
 Helmsdale 
 
 OVARIES. 
 
 Per Cent. 
 
 Total per 
 Fish of 
 Standard 
 Length. 
 
 Per Cent. 
 
 Total per 
 Fish of 
 Standard 
 Length. 
 
 Thick. 
 
 Thin. 
 
 31-2 
 
 35-0 
 
 1700 38-6 
 
 136 
 
 28-3 
 
 30-8 
 
 1670 39-3 225 
 
 28-7 
 
 30-8 
 
 1540 
 
 377 
 
 134 
 
 28-5 
 
 33-1 ! 1860 
 
 38-3 
 
 178 
 
 Average, 29'2 
 
 32-4 
 
 ///. October and November. 
 
 62 I Helmsdale 
 
 ~ I 
 . 1 20-9 
 
 20-5 
 
 850 
 
 37-6 
 
 763 
 
 63 Helmsdale 
 
 : : . 
 
 21-6 
 
 22-1 
 
 805 
 
 38-6 
 
 714 
 
 64 j Dee . 
 
 . , . 
 
 21-98 
 
 25-1 
 
 1030 
 
 38-7 
 
 816 
 
 66 | Helmsdale 
 
 . 
 
 22-5 
 
 28-5 
 
 1010 
 
 39-2 
 
 850 
 
 67 ! Helmsdale j . 
 
 20-6 
 
 22-5 
 
 811 
 
 39-7 
 
 801 
 
 69 Helmsdale 
 
 , - . 
 
 21-5 
 
 22-6 863 
 
 34-7 
 
 940 
 
 70 Dee . 
 
 
 19-4 
 
 22-2 
 
 797 
 
 35-5 
 
 727 
 
 
 Average, 
 
 21-2 
 
 23-3 
 
 880 
 
 37-7 
 
 801 
 
 In these Tables certain fish require special consideration. In the 
 estuary fish of May and June, Nos. 15, 17, and 29 were found to differ 
 so markedly from all the other May to August fish, that they were ex- 
 cluded from the general class. Nothing special is noted as to the 
 appearance of No. 15. In No. 17 the gall-bladder was found to 
 be empty, and in 29 there were no sea lice, and some old wounds were 
 present on the left side. In drawing conclusions from the table 
 it seemed better to exclude these fish, though their inclusion does not 
 invalidate any of the conclusions arrived at. 
 
 In the estuary fish of October and November, Nos. 72 and 79 differ 
 from the others in the large amount of solids in the muscles and 
 the small development of the ovary. They are, in fact, examples of the 
 "winter salmon" of Miescher Ruesch, fish not going to spawn till the 
 ensuing season. They are, therefore, excluded from the general class. 
 
 In the upper- water fish of May and June, one, No. 11, appears 
 abnormal, and it has been excluded in drawing conclusions. Its inclu- 
 sion would merely emphasise the distinction between the upper and 
 lower water fish. 
 
 On taking the average results of this table we find the following : 
 
 [TABLE.
 
 86 
 
 Investigations on the Life- Hi story 
 TABLE II. 
 
 May and June, 
 July and August, . 
 October and November, 
 
 SOLIDS OF MUSCLE. 
 
 Estuary. 
 
 Upper Reaches. 
 
 Per Cent, of 
 Solids. 
 
 Solids 
 per Fish 
 of Stan- 
 dard 
 Length. 
 
 Per Cent of 
 Solids. 
 
 Solids 
 per Fish 
 of Stan- 
 dard 
 Length. 
 
 Thick. 
 
 Thin. 
 
 Thick. 
 
 Thin. 
 
 33-2 
 32-9 
 26-1 
 
 38-7 
 36-1 
 31-3 
 
 2210 
 
 2270 
 1750 
 
 29-8 
 29-2 
 21-2 
 
 32-7 
 32-4 
 23-3 
 
 1710 
 
 1690 
 
 880 
 
 May and June. 
 
 SOLIDS OK OVAKIKS. 
 
 Estuary. 
 
 Upper Reaches. 
 
 Solids per 
 Per Cent, of Fish of 
 Solids. Standard 
 Length. 
 
 Per Cent, of 
 Solids. 
 
 Solids per 
 Fish of 
 Standard 
 Length, 
 
 35-0 47-3 
 
 36 -3 
 
 !)->-) 
 
 July and August, . 
 
 34-4 72-0 
 
 38%5 
 
 168-0 
 
 October and November, 
 
 38-7 545-0 
 
 37-7 
 
 801-0 
 
 Such a table shows : --As regards 
 
 (a) MUSCLE. 
 
 1. The percentage of solids is throughout the season markedly 
 higher in the fish at the mouth than in the fish in the upper 
 reaches of the river. 
 
 2. The percentage remains unaltered both at the mouth and in 
 the upper reaches till August. 
 
 3. In October and November the percentage of solids falls 
 markedly both at the mouth and in the upper reaches. 
 
 4. The October and November salmon in the estuary contain in 
 the thick 7 per cent, and in the thin 8 per cent, more water than 
 the salmon in May, June, July, and August, and thus, though the 
 weight of the muscle does not show a diminution, there is actually 
 a marked diminution in its solid constituents, and its weight is 
 kept up by the addition of water. In the October and November 
 fish in the upper waters, the thick contains 12 per cent, and the 
 thin 15 per cent, more water than the thick and thin of fish in the 
 estuary earlier in the year. This development of a more watery 
 condition of the flesh is of considerable importance in estimating 
 the food value of the salmon.
 
 of the Salmon in Fresh Water. S7 
 
 5. The solids in the fish of standard length undergo no alteration 
 in the estuary fish from May to August, but in October and 
 November there is a marked decrease. 
 
 In the upper-water fish there is practically no change till August, 
 but there is a very marked diminution in October and November. 
 
 (b) OVARIES. 
 
 1. From May to August the percentage of solids is higher in the 
 fish from the upper reaches than in those from the mouth of the 
 rivers. In October and November the ovaries of fish at the mouth 
 have as high a percentage of solids as those in the upper waters. 
 
 2. Throughout the season the total solids of the ovaries in the fish 
 of standard length are very markedly less in fish at the mouth 
 than in fish in the upper waters. 
 
 From these tables a balance of Loss of Muscle and (Tain of Ovaries 
 may be struck : 
 
 A. Balance to 
 
 Average solids of muscle per fish of standard length in 
 
 estuary fish from May to August, - - 2240 
 
 Average solids in muscle per fish of standard length of 
 
 upper- water fish in July and August, 1 690 
 
 Loss, 550 
 
 Average solids per fish of standard length in ovaries of 
 
 estuary fish from May to August, - 59 
 
 Average solids in ovaries in upper -water fish in July and 
 
 August, 168 
 
 Gain, 109 
 
 If 109 of muscle solids go to ovaries, then 441 grms. will be avail- 
 able as a source of energy. 
 
 B. Balance to November. 
 
 Solids in muscle of estuary fish, May to August, - 2240 
 
 Solids in muscle of upper-water fish, October and 
 
 November, - 880 
 
 Loss, 1360 
 
 Solids in ovaries of estuary fish, May to August, 59 
 
 Solids in ovaries of upper-water fish, October and Nov- 
 ember, 800 
 
 Gain, 741 
 
 If 741 of solids of muscle go to ovaries, 619 will be available as a 
 .source of energy. 
 
 The amount of solids lost by the muscle is not only amply sufficient to 
 yield the solids gained by the ovary, but a large surplus is left.
 
 88 Investigations on the I/ife- History 
 
 FEMALE SALMON- 1895. 
 
 Table III. gives the results of the analyses of the amount of solids 
 in the North Esk fish during 1895. 
 
 It corresponds closely to Table I., except as to the solids of the 
 ovaries. Here in July both the percentage amount and the amount per 
 fish of standard length are markedly higher than in the corresponding 
 fish of 1896. 
 
 TABLE III. 
 
 SOLIDS. 
 
 Muscle. Ovaries. 
 
 No. 
 
 Date. 
 
 Per Cent. 
 
 Total per 
 Standard 
 Fish. 
 
 Total per 
 Per ( lent. Standard 
 Fish. 
 
 Thick. 
 
 Thin. 
 
 10 
 
 23.7 33-8 
 
 -54-7 
 
 2004 
 
 41-3 204 
 
 12 
 
 i 35-4 
 
 36-6 
 
 2737 
 
 40-2 17. r > 
 
 Average, . . 
 
 26.10 
 
 34-6 
 
 85*6 
 
 2370 
 1722 
 
 10-7 389 
 
 29 
 
 27-5 
 
 30-2 
 
 38-0 274 
 
 31 28.10 
 
 31-6 
 
 37-9 
 
 2120 
 
 88-5 461 
 
 39 12.12 
 
 23-2 
 
 19-9 
 
 1000 
 
 
 Average, . . 
 
 
 27-4 
 
 29-3 
 
 mil 
 
 38-0 ! 367 
 
 MALE FISH. 
 
 Though the testes increase in size about twenty fold, they do not 
 attain anything like the same proportionate weight of the fish as do the 
 ovaries. In a fish of standard length in the male, 257 grins. 
 of material are laid on to the testes; in the female, 2150 grms. are 
 gained by the ovaries. It is, therefore, highly probable that since the 
 muscles in the female contain sufficient material for the growth of the 
 ovaries, in the male the stored material should be amply sufficient 
 for the growth of the testes. Unfortunately the number of male 
 salmon at our disposal was small. 
 
 Table IV. gives the results of our investigations on the changes < f 
 the solids in the muscle and testes : 

 
 of t/te Salmon in Fresh Water. 
 TABLE IV. SOLIDS. 
 
 MAY AND JUNK. 
 
 River. 
 
 Spey 
 Annan 
 
 Muscle. 
 
 Testes. 
 
 Per 
 Thick. 
 
 Cent. 
 Thin. 
 
 Total 
 per Stan- 
 dard Pish. 
 
 1781 
 
 Per Cent. 
 
 Total 
 per Stan- 
 dard Fish. 
 
 29-2 
 
 34-5 
 
 19-8 
 
 2-14 
 
 31-9 
 
 35-6 
 
 1873 
 
 20-2 
 
 3-30 
 
 30-5 
 
 35-0 
 
 1827 
 
 20-0 
 
 2-72 
 
 JULY AND AUGUST. 
 
 Spev 
 
 
 24-1 
 
 38-1 
 
 2379 
 
 Spey . . 
 
 
 35-0 
 
 39-6 
 
 2526 
 
 
 Average, 
 
 29-5 
 
 38-8 
 
 2452 
 
 17-1 
 18-1 
 
 6-09 
 
 4-73 
 
 OCTOBER AND NOVEMBEH. 
 
 Dee 
 
 
 
 25-9 
 24'9 
 
 28-8 
 26-2 
 
 1607 
 1333 
 
 
 
 
 
 
 
 Average, 
 
 25-4 
 
 27-0 
 
 1470 
 
 26-3 
 25-0 
 
 25-6 
 
 56-1 
 76-1 
 
 Upper Water. 
 MAY AND JUNK. 
 
 Helmsdale . 
 Dee . 
 
 . . . 
 
 32-5 
 
 28-4 
 
 35-5 
 30-0 
 
 2065 
 
 1484 
 
 19-3 
 18-1 
 
 8-1 
 8-0 
 
 
 Average, 
 
 30-4 
 
 32-7 
 
 1774 
 
 18-7 
 
 8-0 
 
 JULY AND AUGUST. 
 
 Helmsdale . 
 
 . .' . 
 
 30-5 
 
 32-1 
 
 Dee . . 
 
 
 30-0 
 
 34-6 
 
 Dee 
 
 
 27-2 
 
 28-1 
 
 
 
 
 
 
 Average, 
 
 29-6 
 
 31-6 
 
 1842 
 1648 
 
 1285 
 
 1592 
 
 OCTOBER AND NOVEMBER. 
 
 17-4 7'7 
 
 14-8 i 14-3 
 
 16-8 I 33-9 
 
 16-3 \ 18-6 
 
 58-3 
 
 Dee . . 
 
 
 20-5 20-4 
 
 865 
 
 22-1 
 
 
 Average, 
 
 20-5 20-4 
 
 M 
 
 22-1
 
 90 
 
 Investigation* on the Life-History 
 
 This somewhat too limited series of observations indicates 
 
 1 . That the male fish coming to the rivers throughout the season 
 
 have a musculature somewhat poorer in solids than the 
 female fish. 
 
 2. That in the upper reaches the percentage of solids is about the 
 
 same as in the female fish. 
 
 3. That the nature of the change in the percentage of solids is the 
 
 same as in the female fish. 
 
 4. That the testes are considerably poorer in solids than the ovai'ies. 
 
 5. That there is in the testes a more marked increase in the per- 
 
 centage of solids than in the ovaries in October and November. 
 
 6. That in the estuary fish, as regards the amount of solids in the 
 
 muscle per fish of standard length, there is a marked increase 
 in July and August, and a decrease in October and November. 
 
 7. That throughout the season the amount of solids in the muscle 
 
 is smaller in the fish in the upper reaches than in those at the 
 mouths of the rivers, and that the difference becomes more 
 and more marked as the season advances. 
 
 TABLE V. 
 
 Solids of Muscle. 
 
 Estuary. 
 
 May and June, 1809 
 
 July and August, - 2452 
 
 October and November, - I 1470 
 
 Upper Water. 
 
 1774 
 
 1592 
 
 865 
 
 8. That the amount of solids in the testes per fish of standard 
 length steadily increases in fish in the estuaries and in fish in 
 the upper waters throughout the season, and that the in- 
 crease is even greater in the sea than in the upper 
 reaches. But since only one upper-reach fish was examined 
 in October and November, too much stress cannot be placed 
 upon this. 
 
 TABLE VI. 
 
 Solids of Testes. 
 
 
 Estuary. 
 
 Upper Water. 
 
 May and June. 
 
 2-72 
 
 8-00 
 
 July and August, - 
 
 4-73 
 
 18-60 
 
 October and November, - 
 
 66-00 
 
 59-30
 
 of tlti; Snl in,-,,, in Fresh Water. 91- 
 
 A balance of the loss of muscle solids and the gain in the solids of the 
 testes may be struck as follows : 
 
 A. Balance to August. 
 
 Solids in muscle of estuary fish from May to August, 
 Solids in muscle of upper-water fish in July and August, 
 
 Loss, 
 
 Solids in testes of estuary fish from May to August, 
 Solids in testes of upper-water fish in July and August, 
 
 Gain, 
 
 Grins. 
 2130 
 1592 
 
 538 
 
 3-7 
 
 18-6 
 
 14-9 
 
 If 14-9 grins, of the solids of the flesh go to the testes, 523 grins, will 
 bf available as a source of muscular energy. 
 
 B. Ihdance to November. 
 
 Solids in muscle of estuary fish from May to August, 
 Solids in muscle of upper-water fish in Oct. and Nov., 
 
 Solids in testes of estuary fish from May to August, 
 Solids in testes of upper-water fish in Oct. and Nov., 
 
 Gain, 
 
 Grins, 
 
 2130 
 
 865- 
 
 1265 
 
 3-7 
 
 59-3 
 
 55-6 
 
 If 55*6 grins, of the solids of the muscle go to the testis, then 1209 
 grins, are available for muscular energy. 
 
 The supply of solids, over that required for the construction of the testes. 
 which is thus available for muscular energy, is considerably greater in the 
 case of them ale than of the fimale fish. 
 
 KELTS. 
 
 Table VII. gives the amount of solids per cent, and in fish of standard 
 length in muscle and ovaries in four of the kelts received in the spring of 
 1897:- 
 
 TABLE 
 
 Solids in 
 
 V1J. 
 
 Kelts. 
 
 
 Muscle. 
 
 I'er Cent. m 
 
 \<> ; 
 
 otal per 
 tandard 
 Fish. 
 
 Ovaries. 
 
 Per Cent. 
 
 Total per 
 Standard 
 Fish. 
 
 Thick. 
 
 1 
 Thin. 
 
 ! 
 
 80 21-87 
 M 2379 
 S2 20-86 
 83 18-62 
 
 22-30 
 25-85 
 2078 
 
 17-69 
 
 1024 
 1178 
 
 934 
 649 
 
 14-14 
 14-68 
 17-13 
 12-24 
 
 6-20 
 9-41 
 14-19 
 7-32 
 
 i 
 Average, ! 21 '28 
 
 21-65 
 
 i 
 
 946 
 
 14-55 
 
 9-28
 
 1)2 Investigations on the Life-History 
 
 The length of these kelts (see Table p. 74) indicates very clearly thnt 
 they belong to the large late-coming fish. They cannot, therefore, be com- 
 pared with the fish in the upper waters in October and November, but 
 should rather be compared with the estuary fish of these months. 
 
 This table shows that : 
 
 1. The percentage of solids in the muscle is slightly less than in the 
 unspawned fish in the upper reaches in October and November, markedly 
 less than in the unspawned fish at the estuaries in these months. 
 
 2. The amount of solids per fish of standard length is no less, perhaps 
 rather greater, than in the unspawned fish in tne upper reaches in 
 October and November, but markedly less than the unspawned fish in 
 the estuaries during these months. Hence the apparent increased sixe 
 of the so-called well-mended kelt is in part, at least, due to increase in 
 the water, and not in the solids of the muscle. 
 
 3. The percentage amount of solids in the ovaries is very much 
 smaller than in fish ascending the rivers to spawn. 
 
 4. The solids of the ovaries per fish of standard length are markedly 
 smaller in amount than in fish ascending the river to spawn.
 
 of the Salmon in Fresh Water. 93- 
 
 8. CHANGES IN THE FATS OF MUSCLE, GENITALIA, 
 AND OTHER ORGANS OF THE SALMON IN FRESH 
 WATER, 
 
 BY D. NOEL PATON, M.D.. F.R.C.P.Eix 
 
 Throughout the animal kingdom the material required for the 
 evolution of energy is to a large extent stored in the body as fats. As 
 is well known, the combustion of one gramme of fats liberates about 
 twice as much energy as the combustion of a corresponding amount of 
 proteids or carbohydrates. In the salmon the ova are largely composed 
 of an oily fluid very rich in fats, and hence for the growth of the 
 ovaries a large store of fats in the body is necessary. 
 
 In this section we have to consider where and how this fat is stored 
 and to what extent it is used as a source of energy and to what extent 
 for the growth of the genitalia. 
 
 METHODS. 
 
 A portion of the organ usually about 30 grins. was preserved 
 in spirit until it was analysed. The spirit was then poured into an 
 evaporating basin and the organ finely powdered in a mortar, added to 
 the spirit, and slowly dried over a water bath. When it had not 
 powdered easily at first, it was again powdered after drying. The 
 muscle readily broke up into very fine small fibrils, while the ovaries 
 and livers were readily reduced to a uniform powder. The powder 
 was placed in a filter paper, the mortar and basin being carefully 
 washed with ether and the ether added to the powder, and was then 
 extracted in a Soxhlet apparatus for two days. If by the end of this 
 time the ether was not absolutely colourless, the process was continued 
 until it became colourless. The ether was distilled off and the fat dried 
 at 100 C. and weighed. By the preliminary heating with alcohol the 
 extraction of lecithin was facilitated. 
 
 This method was used in preference to the more recent procedure of 
 Dormeyer (Pfliiger's Arch. Bd. 65, p. 90), because the residue after 
 extraction of fats was required for the estimation of proteids, phos- 
 phorus, and iron. To have put aside separate specimens for the 
 analysis of each of these would have increased the accumulation of 
 material to an unmanageable extent. As it was, no less than six or 
 seven bottles of material were put aside for each fish. 
 
 In face of Dormeyer's severe strictures upon Soxhlet's method it was 
 necessary to test it carefully against the method devised by the former. 
 
 Dormeyer found that with horse flesh Soxhlet's method of extraction 
 failed to remove a very considerable portion of the fats, and he recom- 
 mends that after an initial extraction bv Soxhlet's method the residue
 
 D4 Investigations on the TAfe- History 
 
 should be submitted to artificial gastric digestion, by which the muscle 
 fibres are dissolved and the fats liberated. These may then be 
 removed by shaking the fluid with ether. 
 
 The muscle, ovaries, and testes of the salmon after preservation in 
 spirit are readily reduced to a very fine state of subdivision, and have 
 not the tough, fibrous consistence of horse muscle. The ether in 
 Soxhlet's apparatus has thus a much better chance of completely 
 recovering the fats. But to test the method against Dormeyer's, the 
 following experiment was performed on Salmon 44 : 
 
 Ovaries. 38 grms., treated in the usual way yielded 3-841 grins, 
 of extract in Soxhlet's apparatus after two days' extraction. The 
 residue was subjected to peptic digestion for 12 hours, and yielded a 
 brown fluid and a copious residue. The fluid was filtered off, and the 
 residue and paper well washed with ether. The filtrate was extracted 
 with ether in a separation funnel. On distilling and evaporating the 
 ether, 0-022 grm. of residue was obtained *54 per cent, of the total 
 extract. 
 
 Muscle. Of the thick 44 grins, and of the thin 35 grins, were treated 
 in the same way. The residue after digestion was very small in amount. 
 The following are the results : 
 
 
 Extraction by 
 Soxhlet's Method. 
 
 Subsequent Extraction 
 by Dormeyer's Method. 
 
 Thick, - 
 Thin, - 
 
 3-477 
 5-158 
 
 0-008 
 0-007 
 
 In thick, 0-23 per cent, of ether extract. 
 In thin, 0-13 per cent, of ether extract. 
 
 Soxhlet's method as employed by us may thus be considered to give 
 quite satisfactory results in the case of the muscle, and somewhat too 
 low results in the case of the ovaries, but the difference is so small that 
 in calculating the percentage of fats in the ovaries the Soxhlet's extrac- 
 tion gives less than O'l per cent, less than Dormeyer's method. 
 Soxhlet's method, 10-107 per cent.; Dormeyer's method, 10*166 per 
 cent. For our purpose the accuracy of the method is amply sufficient. 
 
 The ether extracts after weighing were preserved in small flasks, and 
 in some the amount of fatty acids were determined by Kossel and 
 Oebermiiller's method (Ztsch. f. phys. Chem. Bd. xiv. 599), while in 
 others the lecithin was estimated in the usual way. 
 
 AMOUNT OF FATTY ACIDS. 
 
 The following determinations show the amount of fatty acids present 
 in the ether extract of the muscle, and indicate that it is very largely 
 composed of ordinary fats : 
 
 TABLE 
 
 I. 
 
 No. 
 
 Per Cent, of Fatty 
 Thick. 
 
 Acids in Ether Extract. 
 
 Thin. 
 
 i 
 
 32 
 66 
 
 74 
 
 86-5 
 89-5 
 91-7 
 
 86-0 
 
 88-5 
 92-2
 
 of the Salmon in Fresh Water. 
 
 95 
 
 FEMALE SALMON, 1896. 
 
 Table II. gives the amount of fats in per cent, and in fish of standard 
 length in the " thick " and " thin " of the muscle, in the whole muscle, 
 and in the ovaries. 
 
 TABLE II. 
 
 ESTUARY FISH. 
 
 May and June. 
 
 So. 
 
 River. 
 
 Muscle. 
 
 Ovaries. 
 
 Per cent. 
 Thick. 
 
 Per cent. 
 Thin. 
 
 Total per 1 
 Standard Percent. 
 Fish. 
 
 Total pei- 
 Standard 
 Fish. 
 
 16 
 20 
 25 
 
 27 
 
 15 
 17 
 29 
 
 Dee. . 
 Helmsdale 
 Helmsdale 
 Dee. 
 
 Average, 
 
 1070 
 10-90 
 8-14 
 11-20 
 
 16-9 
 17-1 
 14-6 
 21-3 
 
 732 
 
 838 
 641 
 861 
 
 9-04 
 9-40 
 9-45 
 8-66 
 
 8 
 13 
 16 
 12 
 
 10-23 
 
 17-9 
 
 768 
 
 9-14 ! 12 
 
 Spey - - - 
 Dee. 
 Dee. 
 
 3-96 
 
 8-85 
 7-10 
 
 7-27 
 
 12-00 
 15-20 
 
 287 
 329 
 510 
 
 11-60 
 8-50 
 7-90 
 
 9-30 
 
 12 
 
 7 
 11 
 
 Average, 
 
 6-64 
 
 11-5 
 
 375 
 
 10 
 
 Average 
 of A & B, 
 
 8-69 
 
 14-9 
 
 r>99 
 
 9-17 11 
 
 July and August. 
 
 36 
 
 Dee. 
 
 8-5 
 
 17-0 
 
 688 
 
 40 
 
 Dee .... 
 
 10-6 
 
 17-8 
 
 867 
 
 45 
 
 Spey . . . 
 
 12-6 
 
 17-3 
 
 862 
 
 51 
 
 
 10-2 
 
 142 
 
 782 
 
 55 
 
 Dee. . . . 
 
 7'5 
 
 15-3 
 
 653 
 
 Average, \ 9-82 
 
 16-8 
 
 770 
 
 6-9 
 
 18 
 
 6-9 
 
 7 
 
 8-7 
 
 13 
 
 9-9 
 
 19 
 
 12-0 
 
 35 
 
 8-9 
 
 18 
 
 October and November. 
 
 65 
 
 Spey 
 
 7-03 
 
 9-8 
 
 562 
 
 973 
 
 151 
 
 73 
 
 Dee 
 
 5-07 
 
 12-1 
 
 403 
 
 1000 
 
 159 
 
 74 
 
 Dee. . . 
 
 415 
 
 8-4 
 
 313 
 
 9-64 
 
 126 
 
 
 Average, 
 
 5-41 
 
 10-2 
 
 426 
 
 9-79 
 
 145 
 
 72 
 
 Dee. 
 
 15-1 
 
 20-0 
 
 1109 
 
 8-05 
 
 7-9 
 
 79 
 
 Helmsdale 
 
 12-6 
 
 20-2 
 
 962 
 
 10-80 
 
 6-8 
 
 
 Average, 
 
 13-3 
 
 20-1 
 
 1035 
 
 9-42 
 
 7-3
 
 Investigations on the Life-History 
 TABLE II. Continued. 
 
 UPPER WATERS. 
 May and fame. 
 
 
 
 Muscle. 
 
 Ovaries. 
 
 No. 
 
 River. 
 
 Per cent. 
 Thick. 
 
 Per cent. 
 Thin. 
 
 Total per 
 Standard 
 Fish. 
 
 Per cent. 
 
 Total per 
 Standard 
 Fish. 
 
 12 
 21 
 
 Spey 
 Helmsdale 
 
 6-87 
 8-90 
 
 9-4 
 13-4 
 
 418 
 656 
 
 12-5 
 12-2 
 
 16 
 26 
 
 31 
 
 Spey 
 
 6-02 
 
 10-2 
 
 384 
 
 10-8 
 
 32 
 
 32 
 
 Dee. 
 
 5-62 
 
 8-1 
 
 383 
 
 10-5 
 
 43 
 
 11 
 
 Spey 
 
 6-63 
 
 10-5 
 
 432 
 
 6-8 
 
 11 
 
 
 Average, 
 
 6-81 
 
 103 
 
 / 448 
 
 105 
 
 29 
 
 July and August. 
 
 
 "' 
 
 1 1 
 
 
 
 37 
 
 Spey 
 
 9-31 
 
 15-8 i 581 
 
 11-7 
 
 41 
 
 42 
 43 
 
 Spey 
 Helmsdale 
 
 575 
 6-35 
 
 10-0 
 
 10-1 
 
 394 
 
 388 
 
 99 
 10-6 
 
 56 
 37 
 
 49 
 
 Helmsdale . 
 
 7-03 
 
 13-2 
 
 540 
 
 11-2 
 
 52 
 
 
 Average, 
 
 7-11 
 
 12-2 
 
 476 
 
 10-8 
 
 46 
 
 October and November. 
 
 62 
 
 Helmsdale 
 
 2-50 
 
 3-13 
 
 107 
 
 9-55 
 
 193 
 
 63 
 
 Helmsdale 
 
 3-34 
 
 4-21 
 
 131 
 
 9-62 
 
 177 
 
 64 
 
 Dee . 
 
 2-68 
 
 6-77 
 
 167 
 
 10-00 
 
 211 
 
 66 
 
 Helmsdale 
 
 6-66 
 
 13-60 
 
 335 
 
 9-83 
 
 213 
 
 67 
 
 Helmsdale 
 
 2-37 
 
 5-59 
 
 121 
 
 9-76 
 
 197 
 
 69 
 
 Helmsdale 
 
 3-72 
 
 6-60 
 
 175 
 
 7-56 
 
 204 
 
 70 
 
 Dee . 
 
 0-62 
 
 4-16 
 
 59 
 
 6-90 
 
 141 
 
 
 Average, 
 
 3-11 
 
 6-34 
 
 159 
 
 9-03 
 
 204 
 
 From tliis Table the average percentage of fats may he calculated : 
 TABLE III. 
 
 May and J une 
 July and August . 
 Oct. and Nov. 
 
 Estuary. 
 
 Upper. 
 
 Thick. 
 
 Thin. 
 
 Ovaries. 
 
 Thick. 
 
 Thin. 
 
 Ovaries. 
 
 10-2 
 9-8 
 5-4 
 
 17-9 
 
 16-8 
 10-2 
 
 9-1 
 
 8-9 
 
 9-8 
 
 6-8 
 7-1 
 3-1 
 
 10-3 
 12-2 
 6-3 
 
 10-5 
 10-8 
 
 *9-0 
 
 *The somewhat smaller percentage may be due to the more difficult extraction of fats from tin 
 ripe ova, which, after preservatiou in alcohol, become hard and difficult to reduce to a powder.
 
 of the, Halm on in freak Writer. 97 
 
 The average amount of fats, per fish of standard length, is given in 
 
 TABLE IV. 
 
 May and June 
 J uly and August 
 October and November . 
 
 Ovaries. 
 
 Muscle. 
 
 Estuary. 
 
 Upper. 
 
 Estuary. 
 
 Upper. 
 
 12 
 18 
 145 
 
 29 
 46 
 204 
 
 768 
 770 
 426 
 
 448 
 476 
 159 
 
 These results closely correspond to the results obtained in the study 
 of the changes in the total solids, but the proportionate changes are 
 even greater. 
 
 1. In the fish coming to the estuaries the percentage of fat and the fat 
 per fish of standard length in the muscle is practically the same from 
 May on to August. The fish coming to the rivers in October and 
 November have a markedly smaller percentage of fat, and a markedly 
 smaller amount per standard fish about three-quarters of the original 
 amount. 
 
 2. J n the ovaries, in fish coming from the sea, the percentage of fat does 
 not alter much throughout the season. In October and November it is 
 slightly higher than in the earlier months. The amount of fat in the 
 ovaries per fish of standard length undergoes no very marked changes 
 from May to August an increase of from 12 to 18 grms. But in 
 October and November there is a rise to 145 grms. This is an eight-fold 
 increase. 
 
 3. In the upper reaches, the fish in July and August show a slight 
 increase in the percentage of fat and in the fat per fish of standard 
 length in the muscle, when compared with the May and June fish. 
 This is probably to be explained by the constant arrival of fresh fish 
 from the sea. In October and November the percentage of fat falls to 
 less than a half of the amount in the earlier months, while the fat per 
 fish of standard length shows a fall of about one-third. 
 
 4. As compared with the fish in the estuaries, the percentage of fat, 
 and the fat per fish of standard length, in these upper-water fish is 
 very much smaller in amount. 
 
 It should perhaps be noted that there is some indication of a 
 division of the upper-water fish, especially from May to August, into 
 two classes, one richer and the other poorer in fat. Thus in May and 
 June number 21 has a much greater amount of muscle fat than the 
 other fish of the class. 
 
 In July and August 37 and 49 have an average of 560 grms., while 42 
 and 43 have only 391 grms. 
 
 At first sight this would seem to indicate that some of these fish have 
 come up earlier than others, and have lost a greater quantity of fat 
 from their muscles. But a comparison of these figures with the total 
 solids and with the proteids opposes the idea that such a distinction can 
 be made. 
 
 5. In the ovaries the percentage of fat is slightly higher in upper- 
 water fish than in the fish from the estuaries, except in October and 
 November. As already pointed out, this is probably an apparent, and 
 not a real difference. 
 
 6. Throughout the whole season the fat per fish of standard 
 G
 
 98 Investigations on the Life-History 
 
 length in the ovaries of upper-water fish is about double that in estuary 
 fish. The amount shows a small, though marked, increase from May 
 to August, and an increase of four and a half times in October and 
 November as compared with the earlier months. 
 
 A balance between fat lo<t from the muscle and fat gained by the 
 ovaries shows the following results : 
 
 (a) Balance to August. 
 
 Muscle. 
 
 Amount of Fat 
 
 in grms. 
 
 Average in Estuary, - May to August, - - 770 
 
 in Upper Waters, - July and August, - - 478 
 
 Loss, 
 
 Average in Estuary, - - May to August, - 15 
 
 in Upper Waters, July and August, - 46 
 
 Gain, 31 
 
 Of muscle fat there goes to ovaries, 31 grra. 
 
 there is available for energy, - 261 grm. 
 
 (6) Balance to November. 
 
 Muscle. 
 
 Average in Upper Waters, - October and November, 159 
 in Estuary, - May to August, - - 770 
 
 Gain, - 611 
 
 Ovaries. 
 
 Average in Upper Waters, - October and November, 204 
 in Estuary, - May to August, - 15 
 
 Loss, - 189 
 
 Of muscle fat there goes to ovaries, - - 189 grm. 
 
 there is available for energy, - 422 grm. 
 
 It is thus manifest that the fat which the salmon has stored in its 
 muscles when it leaves the sea is not only amply sufficient to yield all the 
 fat required for the fats of the growing ovary, but also abundantly suffi- 
 cient to yield energy far an enormous amount of muscular work. When 
 the changes in the proteids of the muscle have been considered, the 
 part played by each of these in the evolution of energy will be dis- 
 
 INTERNAL FAT. 
 (a) Fat of Pyloric Appendages. 
 
 Not only has the salmon leaving the sea this store of fat in its 
 muscles but it has also fat stored in the abdominal cavity round the 
 intestine and in the liver. 
 
 In the salmon the visceral fat is chiefly collected round the pyloric 
 appendages According to Miescher Ruesch (loc. cit.\ p. 179, by the
 
 of the, Salmon in Fresh Water. 99 
 
 beginning of August the intestinal fat has almost disappeared. This 
 observation, of course, applies only to fish in the upper waters. The 
 state of the intestinal fat in fish in the lower waters has not, so far as 
 I am aware, been studied. 
 
 In every fish after Number 20 a note of the fat on the appendages 
 was kept, and the following table gives the results of these observa- 
 tions: 
 
 TABLE v. 
 
 
 Estuary. 
 
 Upper Water. 
 
 No. of 
 Fish. 
 
 Much 
 Fat. 
 
 Little 
 Fat. 
 
 No 
 Fat. 
 
 No. of 
 
 Fish. 
 
 Much 
 Fat. 
 
 Little 
 Fat. 
 
 No 
 Fat 
 
 May and June, 
 
 8 
 
 6 
 
 1 
 
 1 
 
 4 
 
 1 
 
 1 
 
 2 
 
 July aud August, 
 
 13 
 
 9 
 
 4 
 
 
 
 5 
 
 2 
 
 3 
 
 
 
 October and November, 
 
 7 
 
 *3 
 
 3 
 
 1 
 
 8 
 
 
 
 
 
 8 
 
 * Two of these, 72 and 79, were "winter salmon" and are not included in the percentage table 
 below. 
 
 This gives the percentage of fish as follows : 
 TABLE VI. 
 
 
 Estuary. 
 
 Upper Water. 
 
 
 Much Fat. 
 
 Little Fat. 
 
 | Much Fat. 
 
 Little Fat. 
 
 No 
 
 Fat. 
 
 May and June, 
 
 75 
 
 12 
 
 12 
 
 25 
 
 25 
 
 
 
 July and August, 
 
 39 
 
 31 
 
 
 
 40 
 
 CO 
 
 
 
 October and November, . . 
 
 20 
 
 60 
 
 20 
 
 
 
 
 
 100 
 
 In order more accurately to show the extent of the change in the 
 intestinal fat a series of analyses were made from fish at the mouth and 
 from fish in the upper reaches of the rivers throughout the season. The 
 examples selected for this were average specimens. 
 
 METHOD. 
 
 The pyloric appendages with the upper part of the intestine were 
 preserved in spirit. They were then chopped up, and repeatedly ex- 
 tracted with hot alcohol, the alcohol being filtered hot. The residue 
 was then repeatedly extracted with ether. The alcoholic residue was 
 dried over the water bath, and repeatedly extracted with ether, the 
 ether being united with that from the residue. The ether was dis- 
 tilled off, and the fats weighed in the usual manner. 
 
 Table VII. gives the results of these analyses : 
 
 [TABLE.
 
 100 
 
 Investigations m> the. Life-History 
 
 TABLE VII. 
 FATS OF PYLORI c APPENDAGES. 
 
 May to August, - 
 
 Oct. and Nov., 
 
 Estuary Fish. 
 
 Upper-Water Fish. 
 
 No. 
 
 ?' fiJJSi 
 
 Fat - Fish. 
 
 No. 
 
 Total 
 Fat. 
 
 Fat per 
 Standard 
 Fish. 
 
 27 
 
 11-744 28-4 
 
 31 
 
 2-440 
 
 5-73 
 
 45 
 
 14-085 33-4 
 
 32 
 
 (i-930 
 
 11 -iJ 
 
 41 
 
 20-856 58-0 
 
 4.3 
 
 4-987 
 
 17-3 
 
 73 
 
 2-103 2-88 
 
 69 
 
 0-506 
 
 1-24 
 
 74 
 
 3-812 5-06 
 
 70 
 
 0-43.5 
 
 1-50 
 
 72 
 
 47-429 67-2 
 
 
 
 
 79 
 
 Enormous quantity 
 of fat, more than in 
 72. This was lost in 
 analysis by break- 
 ing of flask. 
 
 
 
 
 These figures indicate : 
 
 1st, That in the early part of the season there is a marked difference 
 as regards the amount of intestinal fat in fish at the mouth and in fish 
 in the upper reaches. 
 
 2nd, That in October and November the amount of fat on the append- 
 ages of the fish coming to the mouth of the river has greatly diminished. 
 
 3rd, That the "winter salmon" appearing at this time, 72 and 79, i.e., 
 fish not ready to spawn till the next season, have an enormous accumu- 
 lation of fat on the intestine. 
 
 Taking the averages from May to August of estuary fish and fish iu 
 the upper waters, it is found that 28-5 grm. of fat per standard fish is 
 used up. 
 
 From these results it would appear that this intestinal fat is the first to 
 be drawn upon, and that it is used up more rapidly than the muscle fat. 
 
 (b) Liver Fat. 
 
 In many fish, such as the cod, the great accumulation of fat occurs iu 
 the liver. I have shown elsewhere ("Journal of Physiol. ," vol. xix, p. 1 72) 
 that as much as 67 per cent, of fat is found in the liver of the Gadidae. 
 
 In the female salmon there is never such an accumulation of liver 
 fat, In 1895 the amountof fat in theliver of several fish was determined, 
 and no marked change was observed from July to October in fish in the 
 estuary. 
 
 In 1896 the liver fats were determined in four average fish : 
 
 TABLE VIII. 
 
 Estuary Fish. 
 
 Upper-Water Fish. 
 
 No. 
 
 Per Cent. 
 
 Fat per Standard 
 Fish. 
 
 No. 
 
 Per Cent. 
 
 Fat per Standard 
 Fish. 
 
 27 
 
 17-90 
 
 29-7 
 
 69 
 
 3-39 
 
 4-66 
 
 45 
 
 8-65 
 
 20-5 
 
 70 
 
 3-33 
 
 3-94
 
 of the Salmon in Fresh Water. 
 
 101 
 
 The livers of the two exceptional fish 72 and 79 from the mouth of 
 the river in November yielded the following amounts of fat : 
 72 Per Cent, 12-56. Per Standard Fish, 2M. 
 
 79 5-76. 10-2. 
 
 These figures show that the fats stored in the liver while the fish is 
 feeding in the sea are to a great extent lost during the sojourn in fresh 
 water. As much as 20 grin, of fat per fish of standard length may he 
 given off from the liver. 
 
 FEMALE SALMON, 1895. 
 
 Table IX. gives the analyses of fats in the North Esk salmon of 1895. 
 
 It agrees with Table II. except as regards the ovaries. A greater 
 percentage and actual amount of fat is present in these North Esk fish 
 in July than in the 1896 fish of the same month : 
 
 TABLE IX. 
 
 
 
 Muscle. 
 
 Ovary. 
 
 
 
 
 
 
 
 1 
 
 No. 
 
 Date. 
 
 Per Cent. 
 
 Total per 
 
 
 Total per 
 
 
 
 
 Q, 1 1 
 
 PPT- Ppnt 
 
 ^ j i J 
 
 
 
 Thick. 
 
 Thin. 
 
 Fish. 
 
 
 Fish. 
 
 10 
 
 23.7 
 
 9-4 
 
 14-3 
 
 625 
 
 10-3 
 
 51 
 
 12 
 
 
 
 12-7 
 
 14-9 
 
 1015 
 
 10-7 
 
 47 
 
 
 Average, 
 
 11-0 
 
 14-6 
 
 820 
 
 10-3 
 
 49 
 
 29 
 
 26.10 
 
 6-4 
 
 10-3 
 
 449 
 
 8-2 
 
 59 
 
 31 
 
 28.10 
 
 9-6 
 
 18-7 
 
 795 
 
 9-5 
 
 114 
 
 39 
 
 12.12 
 
 5-1 
 
 1-9 
 
 212 
 
 10* 
 
 210 
 
 
 Average, 
 
 7-0 
 
 13-3 
 
 465 
 
 9-2 
 
 127 
 
 
 
 I 
 
 
 
 
 * Analysis lost. Average from others. 
 
 MALE FISH. 
 
 In the male salmon the testes are comparatively poor in fats. For 
 their development there is no need of the same storage of fats as in the 
 case of the growth of the ovaries. It is thus a matter of very consider- 
 able interest to ascertain whether in the male fish the same accumulation 
 of fat in the muscle occurs as in the female, and whether this fat is used 
 up to the same extent. 
 
 Table X. gives the results of the analyses of the fat in male fash 
 during 1896: 
 
 [TABLK.
 
 Investigation* on. the /,//?'- 
 TABLE X. 
 ESTUARIES. 
 May and June. 
 
 No. 
 
 River. 
 
 Muscle. 
 
 Testes. 
 
 Per Cent. 
 
 Total per 
 Stan- 
 dard 
 Fish. 
 
 Per Cent 
 
 Total per 
 Stan- 
 dard 
 Fish. 
 
 Thick. 
 
 Thin. 
 
 13 
 19 
 
 Average, 
 
 5-97 
 11-5 
 
 13-1 
 17-7 
 
 452 
 
 730 
 
 3-2 
 5-6 
 
 :34 
 
 87 
 
 8-73 
 
 15-4 
 
 591 
 
 4-4 
 
 6 
 
 July and August. 
 
 56 
 59 
 
 Average, 
 
 10-7 
 12-3 
 
 17-7 
 19-1 
 
 865 
 980 
 
 3-7 
 2-9 
 
 73 
 1-04 
 
 11-5 
 
 18-4 
 
 922 
 
 3-3 
 
 88 
 
 71 
 75 
 
 October and November. 
 
 3-3 
 2-9 
 
 ~*T~ 
 
 7-16 
 9-00 
 
 8-08 
 
 Average, -. . . - 
 
 4-0 
 
 2-8 
 
 9-6 
 5-6 
 
 326 
 183 
 
 254 
 
 3-4 
 
 7-6 
 
 UPPER WATER. 
 May and June. 
 
 762 
 359 
 
 
 26 
 34 
 
 Average, 
 
 11-1 
 
 6-1 
 
 15-7 
 9-6 
 
 4-8 
 3-3 
 
 2-02 
 1-45 
 
 8-6 
 
 12-6 
 
 561 
 
 4-0 
 
 1-73 
 
 July a/id August. 
 
 38 
 39 
 54 
 
 Average, . 
 
 8-2 
 8-4 
 4-5 
 
 10-7 
 14-4 
 6-9 
 
 5-24 
 523 
 238 
 
 3-3 
 1-9 
 1-9 
 
 l'-46 
 1-87 
 3-91 . 
 
 7-0 
 
 10-6 
 
 428 
 
 2-3 
 
 2-41 
 
 October and November. 
 
 68 
 
 
 2-2 
 
 3-4 
 
 103 
 
 2-3 
 
 6-34
 
 of the Salmon in Fresh Water. 
 The average results of this table may be given as follows : 
 
 A. Musde. 
 TABLE XI. 
 
 PER CENT. CF FATS. 
 
 J03 
 
 lay and June, 
 "uly and August, . . ." 
 )ctober and November, . 
 
 Estuary. 
 
 Upper Water. 
 
 Thick. 
 
 Thin. 
 
 Thick. 
 
 Thin. 
 
 8-7 
 11-5 
 3-4 
 
 15-4 
 18-4 
 7-6 
 
 8-6 
 7-0 
 2-2 
 
 12-6 , 
 16-0 
 3-4 
 
 TABLE X[J. 
 FAT PER FISH OF STANDARD LENGTH. 
 
 May and June, 
 July and August, . 
 October and November, . 
 
 Estuary. 
 
 Upper Water. 
 
 591 
 922 
 254 
 
 561 
 428 
 103 
 
 B. Testes. 
 
 TABLE XIII. 
 
 FAT IN PERCENTAGE AND PER FISH OF STANDARD LENGTH. 
 
 May and June, 
 July and August, . 
 October and November,. 
 
 Estuary. 
 
 Upper Water. 
 
 Per Cent. 
 
 Per Stan- 
 dard Fish 
 
 Per Cent. 
 
 Per Stan- 
 dard Fish 
 
 4-4 
 3-3 
 3-1 
 
 0-6 
 0-88 
 8-08 
 
 4-0 
 2-3 
 2-3 
 
 1-73 
 2-41 
 6-34
 
 104 Investigations on the Life- History 
 
 The fat balance in male fish is given below : 
 
 A. Balance, to August. 
 
 Muscle. 
 
 Gnus. 
 
 Average in estuary fish from May to August, . .756 
 Average in upper-water fish in July and August, . 428 
 
 Loss, . 328 
 Testes. 
 
 Grms. 
 
 Average iu estuary fish from May to August, . . 0'74 
 
 Average in upper- water fish in July and August, . 2*41 
 
 Gain, . 1'67 
 
 The testes thus accumulate 1'67 grins, of fat, and thus 326 grms. of 
 fat are available as a source of energy. 
 
 B. Balance to November. 
 
 Muscle. 
 
 Grms. 
 
 Average in estuary fish in May arid August, . . 756 
 Average in upper- water fish in October and November, 103 
 
 Loss, . 819 
 Testes. 
 
 Grms. 
 
 Average in estuary fish in May and August, . . 0*74 
 Average in upper- water fish in October and November, 6- 34 
 
 Gain, . 5-46 
 
 The testes take up 5-46 grms. of fat, and thus 813-5 grnis. are left 
 as a source of energy. 
 
 On comparing these figures with the results obtained from female 
 salmon it will be seen that the accumulation of fat in the muscles is as 
 great in the male as in the female, and that the fat is used up to quite as 
 great an extent. On the other hand, the accumulation of fat in the testes 
 is trifling in amount, and thus the conclusion is indicated that in the 
 male the utilisation of fat as a source of energy is much greater than in 
 the female. This is especially marked in the later months. 
 
 INTERNAL FAT. 
 A. Pyloric Appendages. 
 
 The storage of fat on the pyloric appendages of male fish was not 
 inve>tigated by analyses. 
 
 Some observations were, however, made upon the fats of the liver 
 during the season 1895. 
 
 Table XIV. gives the results of these :- 
 
 [TABLK.
 
 >f the Salmon in Fresh Water. 
 TABLE XIV. 
 
 105 
 
 No. 
 
 Date. 
 
 Solids. 
 
 Fats. 
 
 4 
 
 6.7 
 
 39-5 
 
 12-9 
 
 5 
 
 10.7 
 
 35-9 
 
 19-7 
 
 6 
 
 10.7 
 
 38-1 
 
 24.5 
 
 19 
 
 8.8 
 
 42-6 
 
 28-0 
 
 10 
 
 12.12 
 
 20-3 
 
 1-5 
 
 43 
 
 24.12 
 
 18-9 
 
 3-1 
 
 All the fish except 40 and 43 were from the estuaries, but these two 
 fish were taken from the spawning beds. 
 
 KELTS. 
 
 Table XV. gives the amount of fats in the muscles and ovaries of 
 the female kelts analysed : 
 
 TABLE XV. 
 
 
 
 Muscle, 
 
 
 No. 
 
 Per Cent. 
 
 Total per 
 .Standard 
 Fish. 
 
 Thick. 
 
 Thin. 
 
 80 
 
 2-27 
 
 3-95 
 
 125 
 
 81 
 
 4-79 
 
 8-05 
 
 278 
 
 32 
 83 
 
 1-86 
 92 
 
 2-98 
 1-09 
 
 9ti 
 34 
 
 Average, 
 
 2-43 
 
 4-02 
 
 133 
 
 Ovaries. 
 
 2-14 
 2-28 
 4-43 
 1-64 
 
 2-62 
 
 Total per 
 Standard 
 
 94 
 1-46 
 3-67 
 
 1-76 
 
 These observations bring out the following points : 
 
 1. The per cent, of fats in the muscle is only slightly lower than 
 in the upper-water fish of October and November, but markedly lower 
 than in the estuary fish of these months.* 
 
 2. The same applies to the amount of fats per fish of standard length. 
 3 The percentage of fats in the ovaries is markedly lower than in 
 
 any of the fish ascending the rivers. 
 
 4. The amount of fats per standard fish is still lower. 
 
 * It has been shown (p. 92) that it is with these estuary fish that the kelts must be 
 compared.
 
 100 Investigations on the Life-History 
 
 9. MICROSCOPICAL OBSERVATIONS ON MUSCLE 
 FAT IN THE SALMON. 
 
 15Y S. 0. MAHALANOBIS, B.Sc., F.R.M.S. 
 
 The chemical observations on the changes in the fats of the salmon 
 during its .sojourn in fresh water have .shown that the fish leaves its 
 marine feeding ground with the muscles loaded with fat, and that this 
 fat gradually diminishes in amount, being in part transmitted to the 
 ovary and in part used up as a source of energy. 
 
 The object of the present enquy-y is to investigate more fully the 
 nature of this change. 
 
 On this subject Miescher Ruesch says (p. 186) : * 
 
 " That the lateral trunk muscles are the actual source of material 
 both for the nourishment of the animal and for the ripening of the 
 genitalia, is rendered evident by the microscope. Even the winter and 
 spring salmon show a sometimes more, sometimes less, well marked 
 series of fat droplets chiefly between the fine, cross-striped, elementary 
 fibrillse of the unequally thick muscle fibres, especially in the thinner 
 ones, such as we recognise as a sign of the so-called degeneration of muscle 
 fibres. The amount of these fat droplets increases to mid-summer, when 
 the ovary begins to grow more rapidly, and may lead to many fibres 
 becoming opaque. A separate thin muscle plite which lies along the 
 side of the body just under the skin degenerates most markedly. On the 
 other hand, all the remaining muscles of the breast, belly, back and anal 
 fins, of the jaw and hyoid bone, the upper and lower longitudinal muscles 
 (Langsmuskel), and the tail muscle, in the stricter sense, continue, so to 
 speak, fully intact and free of fat." 
 
 Again on p. 208 he says : " . . . the trunk muscles, which already 
 in the salmon in March, nay even in the winter salmon (December), 
 show clear traces of commencing fatty degeneration (Fettentartung)." 
 
 On p. 215, in describing the condition of the fish on the spawning 
 beds, he says : The flesh of the trunk is entirely opaque, whitish, and 
 entirely filled with fat droplets." As will Le seen presently, our obser- 
 vations do not agree with this last description. 
 
 Miescher then goes 011 to develop a theory of the liquidation and 
 fatty degeneration of the muscles. After referring to the influence of 
 diminished vascular supply and diminished respiration upon the meta- 
 bolism, he concludes that the changes in the muscle arc caused by the 
 diminution in the blood supply. 
 
 It is thus a matter of very considerable importance to re-investigate 
 the microscopic appearances of the muscle fibres and to determine how 
 far Miescher is correct in his conclusion that a fatty degeneration 
 occurs. 
 
 It has already been shown (p. 93) that the salmon feeds during the 
 time it remains in the sea, and that a store of fat appears in the muscles, 
 which is evidently used up for the -nutrition of the animal, as well as the 
 ripening of the generative organs, during its sojourn in the river. 
 
 The results of the chemical examination clearly point to two facts : 
 First, both at the mouth of the river and in upper water there is a fall 
 in the amount of muscle fat from May to November, the amount of fat 
 
 * Statistische und biologische Beitrage, " Zur Kenntniss von Leben dea Rheinliirhsos
 
 of the Salmon in Fresh-Water. 107 
 
 in November fish being about half that in May fish. Second, there it 
 an enormous difference between the average amount of fat in fish at the 
 mouth and the average in those in the upper water during the later 
 months of the year. 
 
 The exact nature of this change in the amount of fat can only be 
 satisfactorily understood when the results of chemical examination are 
 supported by histological evidences. 
 
 1. METHODS. 
 
 Pieces of the lateral trunk muscle both thick and thin, i.e. dorsal and 
 abdominal, from each fish, were fixed in (a) sat. sol. of corrosive subli- 
 mate, and (b) in 1 per cent, solution of osmic acid for 24 hours, then 
 thoroughly washed, hardened in alcohol in the usual way, and quickly 
 dehydrated. They were embedded in paraffin, and longitudinal as well as 
 transverse sections of to 8 microns thickness were cut. Various solvents 
 of paraffin, e.g. cedar oil, xylol, clove oil, benzole, were tried before 
 embedding, and xylol was found to % answer best in preserving the fat. 
 The sections were mounted on albuminised slides to afford every facility 
 for the preservation of fat. It was found by experiments that fixing 
 tissues in reagents other than osmic acid, and afterwards treating the 
 sections with osmic acid, did not give satisfactory results. Sections fixed 
 in corrosive sublimate were stained with some suitable double stain such 
 as hyernatoxylin and eosin or methyl-blue and eosin. The fat in these 
 sections was, to a great extent, washed out, and they then served for 
 comparison with the osmic acid sections, and helped in the study of the 
 general change in the muscles. 
 
 'Ihe reduction of osmium in sections fixed in osmic acid revealed tin- 
 presence of fat globules in a most perfect manner, and it only needed 
 some single stain, e.g. eosin, to bring out other details. Tissues fixed in 
 osmic acid are rather difficult to stain, but eosin seemed to answer the 
 purpose well. 
 
 II. RESULTS OF EXAMINATION OF THE SECTIONS. 
 A. THOSE FIXED IN PERCHLORIDE OF MERCURY. 
 
 1. M-ttscle Fibres. The size of the muscle fibres varied very much, 
 from 50 to 167 microns in diameter, the largest size being in early 
 fish from the mouth of the river. In two specimens caught at the 
 mouth in August, the fibres were about 134 microns in diameter. In 
 those from the upper reaches the size of the fibres varied from 50 to 
 100 microns in diameter, the smallest size being in the thin or 
 abdominal muscle of specimen No. 63, a fish caught in October. 
 
 '2. Mriation. In longitudinal sections the transverse striatkms were 
 well seen in fibres in the centre of a bundle, whereas the fibres at the 
 periphery showed, in many cases, a tendency to longitudinal cleavage, 
 and there the transverse striation was obscure. This longitudinal 
 cleavage was most pronounced in fish from the mouth of the river. 
 
 3. Muscle Vibrillce. The size of the iudividul fibrils in muscle fibres 
 seemed fairly constant in all specimens, being of 1-5 microns to 1'8 
 microns in. diameter. The number of Conheirn's ureas varied with the 
 size of the fibres. 
 
 4. _Nnd<',nu. The longitudinal sections showed well-marked, rather 
 elongated nuclei. No change was noticed in the different specimens 
 except that in No. 79 they were very prominent, but there w.is no 
 Indication of any active proliferation having taken place. 
 
 5. Amount of Fat. The amount of fat in specimens fixed in corrosive 
 sublimate 1 could only bo approximately ascertained by the honeycomb 
 like appearance of tlio emptv spaces in the connective tissue left by the 
 t'at cells, and by a comparison with the osmic acid preparations. In the 
 
 iwH this layer of empty spaces shows an average of hmn. in
 
 108 Investigations on the Li fc- History 
 
 thickness in the case of fish leaving the sea early in the year ; whereas 
 towards the end of summer and in autumn I find an average of -^min. 
 thick. For the amount of fat in the endami/sixm, as well as the iiitra 
 cellular fat, we must depend on osmic acid preparations. 
 
 B. THOSE FIXED WITH OSMIC ACID. 
 
 J . Fat between Muscle Fibres. In fish coming from the sea there is 
 an abundance of fat cells between the muscle fibres, but in fish that have 
 been for some time in the r,ver this fat has almost entirely disappeared. 
 Fig. 4 is from an upper-water fish, hence even in this longitudinal 
 section we notice a marked absence of intercellular fat, whereas Fig. 5, 
 being from No. 79 (a fish fresh from the sea), shows, even in the trans 
 verse .section, presence of abundance of fat. 
 
 2. Fat Inside the Muscle Fibres. Treatment with osinic acid ex- 
 plained the cause of longitudinal cleavages in the muscle fibres, and 
 revealed the presence of tine granules of fat along the cleavage lines 
 between bundles of fibrils, also between individual fibrils (Fig. 1). 
 In transverse sections also these granules can be seen lodged between 
 the fibrils. (Fig 2.) 
 
 To make sure that these iiiterjibrillary granules of fat were not just 
 small particles broken up from connective tissue-fat and scattered over 
 the sections during washing, etc., every slide, during the whole process, 
 was kept in a vertical position with a marked end always upward ; so 
 that all flow of particles, if there were any, would be in one direction 
 only ; but the specimens show a very uniform distribution of these 
 granules. 
 
 The amount of this intracelhdar fat varies very much at different 
 periods. In early fish the amount is much greater and the granules 
 much larger than in late fish. 
 
 In the fish leaving the sea this accumulation of fat in the fibres 
 sometimes reaches an enormous amount, and a thick layer occurs under 
 the sarcolemma. This will be evident from a comparison between Fig. 
 2 and Fig. 3, the former being from a late fish, 69, and the latter 
 from No. 79. 
 
 Chemical analyses showed the amount of fat in these fish to lie, in per 
 cent : 
 
 Thick. Thin. 
 
 G9 3-7 6-6 
 
 79 12-6 20-2 
 
 Summing up the results of the examination of the specimens fixed in 
 corrosive sublimate and of the corresponding ones in osmic acid, we 
 find that the evidence of the microscope tallies with the result of the 
 chemical examination, and points not only to a change in the amount, 
 of muscle fat, but also, to some extent, in the nature of its distribution, 
 at different periods. The early fish at the mouth of the river have a 
 much greater amount of fat in the muscles (both intercellular and 
 intracellular) than the late fish in the upper rea< lies. 
 
 This diminution of muscle fat in the late fish may be due to a want of 
 fresh accumulation or to an increasingly active removal. But the 
 enormous difference in amount between a fish like No. 72 or No. 79 
 and one that is about to spawn, cannot be accounted for by either of 
 these causes singly. There is, no doubt, more active removal of fat- 
 probably slightly due to increased amount of work in going up the 
 river but mainly due to an export to the generative organs. A fish 
 like No. 79 has a very small ovary and large amount of muscle, 
 whereas a fish about to spawn has a very large ovary and small amount 
 of muscle. This obviously points to the fact that in the late fish the 
 ovary grows at the expense of the muscles. At the same time, it is 
 evident that if during the growth and development of the sexual
 
 of the Salmon in Fresh Water. 109 
 
 organs there had been fresh accumulation of fat or, in other words, if 
 the animal had been actively feeding the equilibrium would have 
 been maintained an4 the muscles would not have lost, at all events, to 
 such an extent. 
 
 It would appear, then, that the fats taken in its food by the salmon 
 in the sea accumulate between the muscle fibres and also inside the fibres 
 between the fibril-, and that during the sojourn of the fish in the river 
 these fats steadily diminish, being either used up as a source of energy 
 by the muscle, or transported from the muscle to the growing ovaries. 
 They do not bear out Miescher Ruesch's description of the condition of 
 the muscles in the spawning fish, and they entirely oppose his view 
 that anything of the nature of a fatty degeneration occurs. 
 
 The results of this investigation throw some light on the so-called 
 " fatty degeneration of muscle." Endless controversy has raged to 
 decide the question of direct formation of fat from proteids in the 
 cell. The results of Pettenkofer and Voit's classical experiments, the 
 evidence of the formation of fat from blood by maggots, and the fatty 
 change in the ripening of cheese have been recently dealt with by 
 Pfliiger (*) who shows that the evidence is far from conclusive. The 
 argument of " f titty degeneration of muscle" is the sheet anchor to 
 the supporters of the theory of the proteid-origin of fat. But even 
 with that their position is not secure, as has been pointed out by Dr Noel 
 Paton (t). Pathologists usually fall into the error of depending on the 
 evidence of the microscope only, without making thorough chemical 
 investigation. But it has been pointed out by Krehl (J)th;it, hearts, 
 showing the characteristic microscopic symptoms of fatty degeneration, 
 may have less than normal amount of fat. In this investigation I had 
 the advantage of comparing microscopical observations with the results 
 of careful chemical examination made by Dr. Noel Paton. 
 
 A glance at the Figures 1, 2, and 3 will at once show that it 
 would be rather rash to come to a conclusion depending on the evidence 
 of the microscope alone. Here we have the appearance at least 
 resembling the so-called " fatty degeneration " of muscle. But how 
 can there be any fatty degeneration unless the fat is formed at the 
 expense of the proteid molecules of the muscle fibres ? The simple fact 
 that the extremely minute granules of fat are found to arrange them- 
 selve between the fibrils is no proof of their formation from the muscle 
 substance. Fraser and Bruce () have described a somewhat similar 
 appearance in the sections of the tibialis posticus muscle from a case of 
 diabetic neuritis, and called it " disseminated interfibrillary fatty 
 degeneration" ' suggt sting, at the same time, the origin of the 
 fat from the cement substance rather than the muscle fibrils. But non- 
 utilization of fat by muscles, due to failure of trophic influence of 
 nerves and want of functional activity, may lead to an accumulation of 
 fat which might be mistaken for fatty degeneration. It has been 
 shown here that microscopic appearances, such as are described by the 
 pathologists as typical of fatty degeneration, may be found in conditions 
 that are necessary in the economy of Nature. In our specimens, 
 although careful chemical examination detects no diminution of proteid 
 in the muscle substance at all events nothing like the extent which 
 would account for the enormous amount of fat there is the pseudo- 
 evidence of the microscope pointing to so-called " fatty degeneration.' 
 
 It i^ interesting to note that in the African mud tish 
 Protopterus annectens great accumulation of fat appears in the lateral 
 
 O Pfliiger's Arch. 52, 1 and 239. 1892. 
 (t) Journal of Physiology. Vol. XIX. No. 3. 189G. 
 ttl Deutsch. Arch. f. klin. Mod., LI., 416. 1893. 
 () Edinburgh Medical Journal, October 1896.
 
 110 Investigations on the Life- History 
 
 muscles alongside the spinal axis in the tail, which serves as reserved 
 material for the nutrition of the animal, as well as the formation of 
 the generative products, while it passes into a torpid state during the 
 dry season and encloses itself into a cocoon. 
 
 Parker (*) supposes, on the authority of Professor 1 Ziegler, that in 
 Protopterus the lateral muscles in the tail undergo fatty degeneration. 
 He also notices a granular degeneration such as is described by Schneider 
 (t) in the case of Petromyozon fluviatilis. The general appearance of 
 the changes in the muscle fibre resembles that described by Fraser and 
 Bruce (in the case already referred to), inasmuch as " the disintegra- 
 tion occurs in small islands in a muscular fibre." Parker thinks that 
 in Protopterus there appears first a fibrillar change causing a loosening 
 of the muscular substance, followed by a granular degeneration which 
 is probably the precursor of fatty degeneration. 
 
 But, as his observations were made only on specimens in the torpid state 
 (and almost all obtained in July), it would be hardly satisfactory to 
 come to any definite conclusion as regards the nature of the muscle-fat 
 without a comparison of the appearances of the muscle before and 
 after the torpid period, and also at different stages of the same. 
 
 In my specimens of the muscle of salmon (which, as already men- 
 tioned, were taken from fish of different times of the year) I did not 
 notice any granular change. 
 
 It is probable that Protopterus passes into the torpid state with its 
 muscles loaded with a store of fat, which is steadily consumed during its 
 captivity. On this supposition the " fibrillar change " is quite explicable, 
 as will be shown later on, in the case of the salmon. 
 
 On the assumption of actual degeneration of muscular tissue, Parker 
 suggests the probability of the re-absorption of the degenerated 
 products, in Protopterus, lamprey and salmon, being brought about by 
 the agency of wandering leucocytes, after the manner described by 
 Metschnikoff (J). But, at the same time, he recognises the difficulty 
 in the acceptance of such an explanation ; as, Loos () has pointed out 
 that MetschnikoiFs researches regarding the part played by leucocytes 
 in the absorption of tadpole's tail are not conclusive. Whereas, in the 
 case of the salmon, the explanation is rendered invalid by the fact of 
 its depending on data that, I contend, still remain not proven. 
 
 " Fatty degeneration " is at pi-esent a misnomer. This investi- 
 gation and similar other observations strongly suggest that, in many 
 cases, the so-called fatty degeneration is a mere fatty infiltration due to 
 increased accumulation of fat from diminished utilisation in the tissues. 
 Bearing in mind the result of chemical investigation, the appearance in 
 the Figures 1, 2, and 3, at all events, should be de-cribed as inter- 
 fibril lary infiltration of fat. It has already been stated that Figure 
 3 is from a fish fresh from the sea one that had been actively feed- 
 ing, and consequently its blood and lymph were rich in fat, whence, in 
 all probability, the muscle cells absorbed fat and stored it between the 
 fibrils. We know thf>t a dense network of capillaries surrounds the 
 muscle fibres, and although no capillaries enter the fibres, there are 
 lymph spaces surrounding Conheirn's areas and communiciting with 
 those beneath the sarcolemma. As already pointed out, the fat granules 
 in fish leaving the sea are more crowded immediately under the 
 sarcolemma (Fig. 3.). Figure 2 is from a late fish one that had 
 been actively using up the reserve fat, hence the transverse section of 
 
 (*) " Anatomy and Physiology of Protopterus Annectens." Transactions of the Royal 
 Irish Academy. Vol. XXX., Part III., p. 207. 
 
 (t) Beitrage zur vergl. Anat. u. Entwickelungsgesehichte d. Wirbelthiere, Berliu, 
 1879. 
 
 (t) " Untersuch ueb. die mesodermalen Phagocyten einiger Wirbelthiere." Biol. 
 Centralblatt Bd. III. 
 
 () Biol. Centralblatt, IX., 1889.
 
 PLATE I. 
 
 FIG. i. 
 
 x 300.
 
 \
 
 PLATE II 
 
 FIG. 2. 
 
 x 600. 
 
 FIG. 3. 
 
 x 6co.
 
 PLATE III. 
 
 FIG. 4. 
 
 x 50.
 
 PLATE IV. 
 
 FIG. 6. 
 
 x 600. 
 
 FIG. 7. 
 
 600.
 
 of the Salmon in Fresh Water. HI 
 
 the fibres does riot look nearly so crowded with ie, ; the fat granules are 
 much smaller and more scattered, and the masses ao the periphery of 
 the fibres are all used up. 
 
 A comparison between the appearances of the Figures 2 and 3 
 would suggest the idea of a secreting cell during activity in the case of 
 the former, and at rest in the latter. But it is a mere analogy and 
 cannot be pushed f ,ir, as that would involve a formation of fat bv the 
 protoplasm of the cell. 
 
 As generally stated by pathologist s, and also found in my specimens, 
 the fibres that undergo such fatty changes show indications of dis- 
 appearance of the cross stripes. Tin's loss of transverse striation is 
 usually concomitant with the appearance of marked longitudinal cleavages 
 between bundles of fibrils and also individual fibrils. Hence it would 
 appear that the obliteration, or rather obscuration, of the transverse stria- 
 tion of a fibre is due to the relationship of the individual fibrils in 
 lateral apposition being disturbed, and the intertibrillary spaces being 
 crowded with highly refractile granules of fat. This is shown by Figuie 
 6, where the section was treated with ether to remove the fat 
 granules, and thus render the fibres clearer. Now this section, when 
 loaded with granules of fat, would present a somewhat similar appearance 
 to Figure 7,* which is a typical pathological specimen of "fatty 
 degeneration." Of course the fibres in t'ue mu.scle of salmon are very 
 much coarser than those of human muscle. 
 
 Bogdanow (I"), in an account of his research on the muscle fat in 
 horse flesh, describes that, after a single Soxhlet extraction, most of the 
 fat in the connective tissue disappears, while the muscle fibre treated 
 with 1 per cent, osmic acid stains brown (though lighter than non- 
 extracted fibres) ; this staining gets lighter with each extraction. He 
 adduces this in support of the statement that there exist two fats in 
 flesh. Muscle of fish is much more friable than horse flesh, at least 
 sections treated with ether lose all fat, as shown in 'Figure 6 ; but 
 with prolonged action of alcohol I find that all connective tissue fat 
 (even intercellular fat) disappears, but the interfibrillary fat glanules 
 are not so easily removed, .but from this it does not necessarily follow 
 that the second fat is derived from the muscle plasma, whereas any 
 attempt to prove its production by the muscle cell, owing to its 
 resemblance to milk fat, would ainonnt to " begging the question." 
 
 Scientific scepticism is always a great help towards the establishment 
 of a firm foundation of truth. So the position assumed here is, that 
 the usual microscopical evidence on " iatty degeneration of muscle " 
 cannot be depended upon. A line of demarcation between fatty 
 degeneration and fatty infiltration can hardly be drawn with a steady 
 hand. Many cases of so-called fatty degeneration are merely such 
 interfibrillary infiltration as occurs in the salmon's muscle. Actual 
 breaking down of proteid molecules may take place, but any such state- 
 ment has to be substantiated by resul's of chemical examination. 
 
 DESCRIPTION OF FIGURES. 
 
 THK FIGURES ARE REPRODUCTIONS OF MICRO PHOTOGRAI-HS. 
 Fig. 1. Muscle of salmon leaving the sea, with fat-globules between fibrils. 
 Fig. 2. T.S. muscle fibres of salmon from upper reaches of river with very 
 
 little interfibrillar fat. 
 Fig. 3. T.S. muscle fibres of salmon caught in the sea with abundance of fat in 
 
 the fibres. 
 Fig. 4. L.S. muscle of salmon some time in the river showing little fat between 
 
 the fibres. 
 Fig. 5. L.S. muscle of salmon caught in the sea with abundance of inter-fibrous 
 
 fat. 
 Fig. 6. L.S. muscle of salmon treated with ether to remove fat globules to show 
 
 apparent disappearance of transverse striation. 
 Fig. 7. L.S. human muscle in state of fatty degeneration. 
 
 * This specimen was kindly lent by Dr. Robert Muir, Pathological Laboratory, Edin- 
 burgh University, 
 t Pfluger's Archiv., Bd. LXV.
 
 112 Investigations on the Life-History 
 
 10. THE NATURE OF THE PROTEIDS OF SALMON 
 MUSCLE. 
 
 BY FRANCIS D. BOYD, M.D., F.R.C.P. ED. 
 
 Dr. Dunlop, in his study of the muscles of the salmon during its 
 .sojourn in fresh water, finds that the proteids undergo a marked 
 diminution, being in part transferred to the growing ovary and testis, 
 and in part used as a source of muscular energy (p. 1 20). 
 
 These observations, however, do not deal with the nature of the 
 proteids in muscle, and they leave unii instigated the question of which 
 proteids undergo this diminution. Since in the salmon we have an 
 animal undergoing a very prolonged fast, the subject seemed of interest in 
 relation to the pathology of starvation, and in view of results obtained 
 by previous observers in relation to this question. Thus the investiga- 
 tions of Tiegel (1), Buchart (2), and Salvioli (3) on the question of the 
 blood proteids during starvation have yielded somewhat contradic- 
 tory results, and do not enable us to arrive at any definite conclusion. 
 
 Before considering the changes which the proteids undergo, it was 
 necessary to study the nature of the proteids which occur in the muscles 
 of salmon. 
 
 This paper is thus divided into two sections A. The nature of the 
 proteids of salmon muscle. B. The changes which these proteids 
 undergo during the sojourn of the fish in fresh water. 
 
 A. The Nature, of the Proteids of /Salmon Muscle. 
 2. Soluble Proteids. 
 
 Method. (1) In examining the soluble proteids of the salmon muscle, a 
 portion of about 40 grammes of the flesh was taken, and all the bone 
 and visible fibrous tissue separated. The muscle was then minced, 
 pounded in a mortar, and extracted with normal salt solution. Normal 
 salt solution was used, as von Fiirth (4) has shown that stronger salt 
 solution possesses disadvantages, in that the proteids become altered 
 under the influence of the salt. It was found that all the soluble pro- 
 teid could be extracted by treating the muscle twice with normal saline 
 solution. The mixture thus obtained was filtered under pressure, the 
 filtrate got being a faintly opalescent fluid. The fluid gave all the pro- 
 teid reactions. No precipitation occurred on the addition of 1 per cent. 
 of a 33 per cent, solution of acetic acid. 
 
 A. PROTEIDS COAGULABLE BY HEAT. 
 
 An examination of the fluid extract gave the following result : 
 1. Dialysis. A quantity of the extract was put to dialyse in running 
 water. After 48 hours a copious precipitate was present This preci- 

 
 of the Salmon in Fresh Water. 113 
 
 pitate was separated. When redissolved in normal salt solution it gave 
 the reactions of musculin. The filtrate after the separation of the 
 musculin was subjected to fractional heat coagulation. The following 
 results were obtained : 
 
 38 deg. C. - Very slight opalescence. 
 
 40 deg. C. Decided opalescence. 
 
 45 deg. C. Milky fluid (filtered clear). 
 
 47-5 deg. 0. Faint cloud. 
 
 48 deg. C. - Distinct cloud 
 
 53 deg. C. Precipitate (filtered clear). 
 
 55 deg. C. Faint cloud. 
 
 60 deg. C. Decided cloud. 
 
 62 deg. C. Precipitate (filtered clear). 
 
 64 deg. C. Faint cloud. 
 
 68 deg. C. Very slight precipitate. 
 
 Heated to 80 deg. C. No further precipitate. 
 
 The solution thus contained : 
 
 (a) A proteid coagulated at from 38 to 45 deg. C. This would 
 correspond to the fibrin-like modification of myosin the soluble 
 myosin-fibrin described by Fiirth, rapidly formed at ordinary 
 temperatures from the paramyosinogen, the formation having prob- 
 ably taken place during the filtration of the original extract, a process 
 which even under pressure is necessarily tedious. 
 
 (b) A proteid coagulated at 53 deg C. myosinogin. 
 
 (c) A proteid coagulated at 62 deg. C. myoglobidin. 
 
 (d) A proteid coagulated at 68 deg. C. present in very small amount. 
 It is possible that this proteid is an albumin derived from the blood. 
 From the method in which the salmon flesh was obtained, it was 
 impossible to wash all the blood out of the tissues by perfusion. 
 
 2. Fractional coagulation with ammonium sulphate. To the fluid 
 extract a saturated solution of ammonium sulphate was added in the 
 proportion of 2 parts of the fluid extract to 1*5 parts saturated solution 
 of ammonium sulphate. The mixture then contained about 23 per 
 cent, ammonium sulphate. A copious white precipitate formed. This 
 was thrown upon a filter paper and washed with 23 per cent, solution 
 of ammonium sulphate. On being treated with water the most of the 
 precipitate went into solution. The fluid thus obtained gave all the 
 reactions of proteid of the nature of a globulin. Precipitation with 
 heat occurred at about 50 deg. C. The fluid gave a precipitate with 
 nitric acid, the xanthoproteic reaction and the biuret reaction. The 
 proteid answered closely to musculin or the paramysinogein of Halli- 
 burton (5). 
 
 After treatment of the muscle extract by fractional coagulation witli 
 ammonium sulphate, the filtrate was saturated with ammonium sulphate. 
 A copious precipitate formed. This \vas removed, and the filtrate 
 examined and found to be entirely free from proteid. The precipitate 
 was collected, washed with saturated ammonium sulphate solution, and 
 redissolved in normal salt solution. The solution was clear, of a faintly 
 golden yellow colour, neutral in reaction, and gave all the reactions of a 
 proteid solution. 
 
 Fractional heat coagulation was carried out 
 
 (a), When the extract was rapidly prepared and quite fresh 
 55 deg. C. A faint cloud 
 
 60 deg. C. Marked cloud.
 
 114 Investigations on the Life- History 
 
 (b) When the extract had been allowed to stand 24 hours at the ordi- 
 nary temperature of the room while in the process of filtering. 
 
 40 deg. C. - - Faint opalescence. 
 
 45 deg. C. Decided opalescence. 
 
 46 deg. C. Precipitate (filtered). 
 48 deg. C. Faint opalescence. 
 50 deg. C. ~ Faint opalescence. 
 56 deg. C. More opalescent. 
 
 60 deg. C. Opalescence marked. 
 
 64 deg. C. Faint precipitate separating. 
 
 72 deg. C. Decided precipitate (filtered). 
 
 80 deg. C. No further precipitate. 
 
 Here again may be noted the formation of the soluble myosin fibrin, 
 not precipitable on partial saturation with ammonium sulphate, but 
 precipitable along with the myosinogen on complete saturation with 
 ammonium sulphate the heat coagulation of the soluble myosin-fibrin 
 taking place from 40 deg. C. to 46 deg. C., the myosinogen and myoglo- 
 bulia precipitating at from 56 deg. C. to 64 deg. C. These temperature 
 results slightly differ from the temperature results got by Fiirth in the 
 case of the muscle proteids of dogs and rabbits. 
 
 From numerous observations the myosinogen of salmon muscle 
 appears to coagulate at 55 to 58 deg. C. 
 
 Myosinogen of salmon muscle does not appear to be precipitated by 
 dialysis, thus differing from paramyosinogen. It is completely preci- 
 pitated by heat, gives a precipitate with nitric acid. It does not 
 precipitate on the addition of dilute acetic acid. It gives the xanthro- 
 proteic reaction and the biuret reaction. 
 
 Method. (2) The muscle in some cases was extracted with strong salt 
 (10 per cent. NaCl.) solution. It was then found that if the extracted 
 fluid was rendered acid with acetic acid, as when 1 per cent, of a 33 per 
 cent, solution of acetic acid was added, the whole proteid in the extract 
 became precipitated. Some of the extract was taken and acetic acid 
 added. The precipitate was removed, dried, and estimated. Some of 
 the precipitate obtained with acetic acid was treated with a solution of 
 carbonate of soda, when part went into solution. Thus : 
 
 Total precipitate obtained with acetic acid, 2-415 per cent. 
 
 Soluble in sodic carbonate solution, - - 0-665 
 
 Residue, 1-750 
 
 B. PROTEOSES AND PEPTONE. 
 
 Fischel and Muira (6) have described the presence of peptone in muscle, 
 and Halliburton described a muscle albumose. Halliburton, in his later 
 work, however, has altered his opinion and agrees with Whitfield (7), 
 who shows that protooses and peptone are not found in the muscles of 
 warm-blooded animals. The same can be said of salmon muscle. In 
 examining for proteoses and peptone the fresh muscle was extracted 
 with 10 per cent, salt solution, and the extract filtered under pressure. 
 The filtrate was saturated with ammonium sulphate while boil- 
 ing. On cooling the mixture was filtered. The filtrate was entirely 
 free from proteid, thus showing the absence of peptone. The residue 
 after filtration was treated with water and filtered. The filtrate gave 
 no proteid reaction, showing the absence of albumose. These observa- 
 tions were repeated on half a dozen different fish which were selected 
 under varying life conditions from the estuaries and upper waters of the 
 rivers, and at different times of the year.
 
 of t/ie Salmon in Fresh Water. 115 
 
 C. THE PRESENCE OP ALBUMIN. 
 
 Halliburton describes an albumin as present in muscle plasma. 1 
 have made a very large number of observations on the muscle of salmon, 
 but have been unable to satisfy myself of its constant presence. If the 
 extract of salmon muscle was treated with an equal volume of saturated 
 ammonium sulphate solution and rendered slightly acid with acetic 
 acid, as a rule the entire proteid present was thrown down. If any 
 proteid remained in solution it was a mere trace. The presence of a 
 mere trace of albumin might result from the imperfect washing away 
 of the blood from the flesh, as from the method in which the flesh 
 was obtained it was impossible to perfuse, and so remove all the blood. 
 
 D. NUCLEO-ALBUMIN. 
 
 The presence of nucleo-albumin in muscle is a subject which has been 
 a good deal discussed of late. Whittield (7) expressly denies its 
 presence, stating that myosin is not a nucleo-albumin, because it contains 
 no appreciable quantity of phosphorus in its molecule, because on gastric 
 digestion only an insignificant residue is obtained which contains no 
 phosphorus, and because when injected into the circulation it does not 
 produce in tra vascular coagulation. He concludes that muscle contains 
 no nucleo-albumin, because after digestion it yields only an insufficient 
 residue, and this contains no appreciable quantity of phosphorus. In 
 a still more recent paper Peckelharing (9), however, reaffirms the 
 presence of nucleo-albumin in muscle. 
 
 I have made a large number of observations on the muscle of salmon. 
 In all of them the phosphorus estimation was carried out by Dr. Noel 
 Paton. 
 
 In extracting the proteid different methods were used. 
 
 (1) The flesh was extracted with 10 per cent, salt solution. The 
 extract obtained was filtered first through muslin and then through 
 filter paper under pressure. A large quantity of the extract was taken 
 and to it 1 per cent, of a 'A3 per cent, solution of acetic acid was added. An 
 enormous precipitate was obtained in every case on the addition of the 
 acetic acid.* This precipitate was collected, washed, dissolved in 1 per 
 cent, solution of sodic carbonate, reprecipitated with acetic acid, collected, 
 and redissolved in sodic carbonate solution. The purification was repeated 
 three times. The solution was then injected into the veins of a brown 
 rabbit by Dr. Paton with negative results. It should be noted, how- 
 ever, that since this observation was made Halliburton (12) has pointed 
 out that if nucleo-albumin be subjected to repeated purifications, it loses 
 its power of producing intra- vascular coagulation. 
 
 (^) The precipitate obtained on the addition of acetic acid to the 
 extract made with strong salt solution was separated, washed with 
 acidulated water to free it of inorganic phosphates, and dried upon a 
 porous plate. A small quantity, less than half a gramme, was examined 
 for phosphorus, and a distinct but small trace was found. 
 
 (3) Several specimens of salmon muscle were examined by Peckelhar- 
 ing's method. Five hundred grammes of the salmon muscle was 
 extracted with weak salt solution (1-5 grammes NaCl. per litre). The 
 extract was filtered and the residue again extracted. The fluid thus 
 obtained was filtered, and dilute acetic acid solution added ; a slight 
 precipitate formed. Hydrochloric acid and liquor pepticus were added 
 and the mixture put to digest for 48 hours. A considerable increase in 
 the precipitate took place. It was thrown upon a weighed ash-free 
 
 * It should be noted that the acetic acid solution carried down the entire proteid in 
 solution in most cases.
 
 116 Investigations an the Life- History 
 
 filter paper, washed with water, alcohol, and ether, dried, weighed, and 
 examined for phosphorus. A number of observations were made. 
 Whenever a sufficient amount of muscle (about 500 grammes) was used, 
 phosphorus was found to be present. From this it may be con- 
 cluded that salmon flesh does contain a soluble proteid, in the molecule 
 of which an appreciable quantity of phosphorus is present. From the 
 behaviour of the extract obtained with strong salt solutions, I would be 
 inclined to hold that the soluble proteid was present as a globulin 
 loosely combined with a small quantity of phosphoric acid either as a 
 true nuclein or a pseudo-nuclein. From the results obtained I must 
 agree with Peckelharing, in so far as salmon muscle is concerned, that 
 there is a nucleo-albumin present in the flesh. It is possible that 
 Whitfield's results were got by using small quantities of flesh. 1 myself 
 got the same results when dealing with an insufficient bulk of muscle. 
 These results are confirmed by the observations on the distribution of 
 phosphrous in the muscles (p. 1 45). 
 
 //. Insoluble Proteids. 
 
 Solid Residue after Extraction. The solid residue, after extracting 
 the soluble proteids, was treated in the incubator for 24 hours with a 
 one per cent, solution of caustic soda. The major part of the residue 
 went into solution, the precipitate which remained representing less 
 than a third of the original material : this consisted of collagen. The 
 solution gave a copious precipitate when rendered faintly acid and 
 treated with alcohol. It gave reactions of. a proteid solution. Some 
 of the alkaline fluid was rendered faintly acid, then a copious precipitate 
 formed. Liquor pepticus and acetic acid were added, when most of the 
 precipitate disappeared. The mixture was digested for 48 hours, when 
 an increase in the precipitate took place. This precipitate was separated 
 and examined by LJr. Paton, when a distinct, though small, amoiint of 
 phosphorus could be demonstrated. This corresponds with Karajew's (8) 
 results. He found that the muscle of animals contained a body which 
 he termed myostromin a complex phosphorus containing albuminous 
 bodv soluble neither in water nor in neutral salt solutions. 
 
 THE CURD. 
 
 Specimens of curded salmon were examined with a view to ascertain- 
 ing the nature of the curd. 
 
 The flesh was plunged into boiling water for three minutes, when the 
 curd became fixed. The curd was then removed from the muscle and 
 examined. It gave all the reactions of a proteid coagulum. 
 
 It was treated with ether and pounded in a mortar, the residue 
 collected and suspended in water. The fluid gave a marked xanthro- 
 proteic reaction. 
 
 B. Changes in the Soluble Proteids at different seasons of the year, and 
 imder differing conditions. 
 
 A good deal of work has been done on the amount of soluble proteid 
 in the muscle of different warm-blooded animals. Demant (10) places 
 the proportion very low : 0-455 per cent, in the pectoralis major of 
 rabbits. Danilewsky (13), in the case of man, found 3*68 per cent. 
 
 Von Konig (11) gives the composition of the nitrogenous part of the 
 salmon muscle as follows :
 
 of the tial'iiwn. in, Fresh Water 
 
 Per cent. 
 
 of N. containing 
 Sul (stances. 
 
 ! 
 
 Albumin. 
 Soluble Proteids. 
 
 19-39 
 
 3-39 
 
 Fibre. 
 
 11-02 
 
 Gelatin. 
 
 1-50 
 
 In examining the muscle of salmon a mixed specimen of the thick and 
 thin was taken. It was minced, pounded, and rubbed up with an 
 equal weight of common salt ; water was then added to the amount that 
 would give a 10 per cent, solution of salt. The extract was passed 
 through muslin, the residue again rubbed up with salt, water added, and 
 the mixture filtered through muslin. The muscle was extracted in this 
 way till all the soluble proteid had been removed. It was found that, 
 as a general rule, three extractions were sufficient to remove all the 
 soluble proteid. The extract was then filtered under pressure. 
 The proteids were then estimated by heat coagulation and the gravi- 
 metric method. The following Tables show the results : 
 
 ESTUARY. 
 
 River. 
 
 Tweed 
 Tweed 
 Tweed 
 Montrose 
 Helmsdale 
 Helmsdale 
 *Dee 
 
 
 No. 
 
 Date. 
 
 Soluble Proteids. 
 Percentage. 
 
 
 
 
 
 Grammes. 
 
 
 4 
 
 June 
 
 1895 
 
 2-98 
 
 
 
 
 June 
 
 1895 
 
 3-33 
 
 
 2 
 
 June 
 
 1895 
 
 3-3 
 
 
 24 
 20 
 25 
 
 72 
 
 September 
 May 
 May 
 October . 
 
 1895 
 1896 
 1896 
 1896 
 
 3-97 
 2-8 
 2-65 
 3-97 
 
 Average, 3-285 
 
 Tweed 
 Tweed 
 Tweed 
 Tweed 
 
 Helmsdale 
 Spey 
 
 *This fish was in a specially fine state of nutrition. 
 
 UPPER WATER. 
 
 34 
 
 42 
 44 
 
 21 
 69 
 
 78 
 
 November 
 
 1895 2-1 
 
 December 
 
 1895 
 
 2-1 
 
 December 
 
 1895 
 
 2-23 
 
 December 
 
 1895 
 
 2-38 
 
 May 
 
 1896 
 
 2-33 
 
 October . 
 
 1896 
 
 2-33 
 
 November 
 
 1896 
 
 3-1 
 
 Amwicro 9-3R7 
 
 The Tables show a considerable excess of soluble proteid in the fish taken 
 at the mouth of the river as compared with the fish in the upper reaches 
 of the stream. The fish passing up from the sea are in good condition,
 
 118 Iiwestiyaiious on the Life-History 
 
 with a large amount of soluble proteicl in the muscle. As the season 
 advances, and the fish has been up the river for some time, the amount 
 of soluble proteid in the muscle shows a very decided diminution. The 
 muscle is relatively poor in soluble proteid. Danilewsky (13) has shown 
 that in warm-blooded animals the muscles that have least work to do 
 are richest in globulin, the globulin in active muscles being probably 
 used up in doing their work. The same may be held in the case of the 
 fish. It passes up the river with a large store of soluble proteid in its 
 muscle. As time advances and its muscles are called upon to supply 
 energy, not only does the total amount of its muscle greatly diminish, 
 but there is a marked diminution in the proportional amount of soluble 
 proteid in the muscle. This difference is considerable, amounting (as 
 shown in the Tables) to 0-918 grammes per cent, of soluble proteid a 
 percentage loss of 27 per cent. A comparison of this with the results 
 obtained by Dr. Dunlop (p. 124) indicates that probably the proteid 
 lost from the muscle is derived from these soluble proteids. 
 
 There are two fish of special interest. The fish from the Dee (No. 72), 
 the last in the first Table, was noted on arrival to be specially well 
 nourished ; and on estimating the total soluble proteids they were found 
 to be in very large amount. In the case of a kelt which was examined 
 (an ill-nourished, lean fish which had not been down to the sea to feed), 
 the proportion of soluble proteids was unusually low. 
 
 CONCLUSIONS. 
 
 From the foregoing the following conclusions may be deduced : 
 
 (1) The salmon muscle contains three soluble proteids Musculin or 
 Paramyosinogen, Myosinogen, and Myoglobulin. 
 
 (2) That soluble Myosin-fibrin is rapidly formed from Pai-amyosinogen 
 at ordinary temperatures. 
 
 3) That these proteids are of the nature of globulins. 
 
 4) That salmon muscle contains no albumin. 
 
 5) That salmon muscle contains no proteoses and no peptone. 
 
 6) That salmon muscle contains an insoluble albuminous body 
 which contains phosphorus Myostromin, which is probably a globulin 
 combined with a true or a pseudo-nuclein. 
 
 (7) That the curd of salmon muscle is a proteid body. 
 
 (8) That there is a marked diminution in the percentage of soluble 
 proteids in salmon muscle in fish which have been in the river for some 
 time. 
 
 (9) That the muscle of the kelt is very poor in soluble proteid. 
 
 REFERENCES TO LITERATURE. 
 
 1. Tiegel Pfliigers Archiv. Vol. XXXII., s. 278. 
 
 2. Buchart Arch, fiir exper. Path, und Phar. Vol. XVI., .s. 322. 
 
 3. Salvioli Du Bois Reymonds Archiv. fiir Physiol. Suppliment 
 Band. 1879, s. 273. 
 
 4. Von Fiirth Arch, fur exper. Path, und f'har. Bd. 36. 
 1895, s. 235. 
 
 5. Halliburton Journal of Physiology. Vol. Vlll. 1887, p. 188. 
 
 6. Fischel Zeitschr. fur physiol. Chemie. Vol. X., s. 14. Muira 
 Virchow's Archiv. Vol. 01., s. 316. 
 
 7. ~W bitfield Journal of Physiology. Vol. XVI., p. 487. 
 
 8. Kara jew Wratsch. 1895, No. 39, s. 1083. 
 
 9. Peckelharinsr Zeitschr. fUr phys. Chemie. Bd. XXII.. Heft 3, 
 8. 245.
 
 of the Salmon in Fresh Water. 119 
 
 10. Damont Zeitschr. fur physiol. Chemie. Bd. III. 1879,8.241. 
 
 11. Von Konig Die Mensch. Nahrungs und Genusmittel. 2nd 
 Part, s. 179. 
 
 12. Halliburton Journal of Physiology. Vol. XXVII., p. 135. 
 
 13. Danilewsky Zeitschr. fur physiol. Oheinie. Bd. V. 1881. s. 
 158.
 
 120 //trevtigations on the Life-History 
 
 11. THE CHANGES IN THE AMOUNT OF PROTEID 
 IN THE MUSCALATURE AND GENITALIA OF 
 SALMON IN FRESH WATER. 
 
 BY JAMES C. DUNLOP, M.D., F.R.C.P. ED. 
 
 A study of the changes which the proteids of salmon undergo during 
 the time of its ascending rivers and during its stay in fresh water is 
 of interest, not only to those concerned with the marketable 
 value of salmon as a food stuff, but also to the physiologist. In 
 salmon we have an example of an animal which is required, during a 
 long period of starvation, to do a large amount of muscular work, and 
 at the same time to supply a large amount of substance for the require- 
 ments of rapidly developing genitalia. Proteid is certainly required 
 for the growth of the genitalia, and almost as certainly for the pro- 
 duction of some of the energy for muscular work, and for the necessary 
 repair of the energy-yielding mechanism, the muscle ; and so the 
 question arises as to whether the salmon has in itself a sufficiency of 
 proteids to supply these wants when it leaves the sea. Does a com- 
 parison of the fish after their stay in fresh water with fish captured in 
 the estuary as they come from the sea warrant the conclusion that 
 they have been obtaining the proteid required for these purposes from 
 their own tissues ? 
 
 Should there exist a store of proteid in fresh run salmon, 
 it is natural to look for it in the musculature, which is so rich 
 in proteid, and which forms such a large amount of the total weight of 
 the fish. Consequently in this research the proteid of muscle has been 
 fully examined. Of the great requirements for proteids mentioned 
 above, one only, the growth of the genitalia, lends itself to measure- 
 ment, and consequently it is this which is here specially considered, 
 and any proteid consumption not accounted for by it is put down to 
 the other great requirements, the supply of muscular energy .and repair 
 of the energy-producing mechanism. 
 
 A point of physiology, on which this study has a direct bearing, is how 
 far the proteids of one tissue can be called on to supply the wants of 
 another. If this examination of salmon shows that the proteid wants 
 of the genitalia are supplied from the proteids of muscle, it indicates 
 a very large transference from one tissue to another. 
 
 The subject has been previously studied by Miescher Ruesch 
 (Internationale Fisherei-Austellung zu Berlin, 1880). He concluded that 
 a fresh run salmon has an ample store of proteid to meet all its 
 requirements in fresh water. The objections to Miescher's work have 
 been considered in another portion of this Report (page 80). He gives 
 percentage analyses of the proteids in a series of fish, but he made a 
 definite quantitative analysis of the total amount, of muscle proteid in
 
 of the Salmon in Fresh Water. 121 
 
 only two fish, which were both caught in August . He did not make 
 such estimations of fish in the later months with developed genitalia, 
 hut from other observations he argues, that these two fish should have 
 lost a certain quantity of proteid from their muscle, and have gained a 
 certain amount in their gsnitalia, and from this calculation he strikes a 
 balance. But the second factor of this comparison, the condition of the 
 later fish, being more or less hypothetical, cannot be considered 
 sufficiently definite; his balance can only be accepted as a probable but 
 not as an absolutely proved one. 
 
 Thanks to an ample supply of material from the fishery Board, this 
 investigation has been much fuller than Miescher's. A series of fish from 
 the upper and lower waters, at different seasons, have been analysed and 
 compared by the method already described in the introductory section 
 of this Report. The results obtained enable a fairly accurate balance 
 to be struck. 
 
 The method adopted for estimating the proteid of the organs was to 
 determine the nitrogen contained, and from it to calculate the amount of 
 proteid. This method being generally accepted as the most accurate 
 available, does not require consideration. It gives the maximum 
 possible amount of proteid, but its results are invariably too high, there 
 always being present in tissues some extractive nitrogen. Results are 
 stated as the amount of nitrogen, and changes in the amount' of nitrogen 
 are assumed to indicate changes in the amount of proteid. 
 
 In this section of the Report, when using the term proteid, not only 
 are the true proteid s referred to, but also all albuminoid substances. No 
 attempt has been made in this part of the investigation to separate the 
 various proteids and albuminoids from each other. A study of some of 
 the individual proteids will be found in Dr. Boyd's section of the Report 
 (page 112). 
 
 The nitrogen estimations were made by Kjeldahl's method on the 
 dry residue left after the fats were extracted by ether (vide page 93). 
 Knowing the amount of nitrogen in the dry residue, the amount of dry 
 residue in the muscle or ovaries, and the total quantity of muscle or 
 ovaries, the total amount of nitrogen in the muscle or ovaries of the 
 fish is readily calculated. Thus, for an example : 
 
 Fish 36. Ovary weighs 126 grms., the dried residue of this after the 
 extraction of fat was 2 9 -3 per cent., and was found to contain 12*98 per 
 
 . - , 12-98x29-3 , Q 
 cent, nitrogen. Ihe ovary consequently contained - o o 
 
 per cent, of nitrogen, and total amount of nitrogen in the ovary was 
 3-8x126 
 
 = 4 ' 13 grms - 
 
 In the following Tables will be found the results of the analyses. In 
 them the fish have been classified in the same manner as in the earlier 
 sections of this work. The first group considered are the female fish of 
 1896, next the male fish of 1896, then the fish caught in 1895, and 
 lastly kelts. The 1896 females are taken up first, because they form 
 much the largest group.
 
 122 
 
 '.ions on the Life-History 
 
 Exceptionall 
 
 ( Exceptiona 
 1 bladder 
 
 <N 03 < W ^ 
 
 i r- -M r^rr-c; 
 
 C5 GO C^ r l C^ li^ OO 
 
 p^^cr-oooo 
 
 CO CC CO !M CO CO !M 
 
 COCO CO CO CO CO 
 
 O> 1-1 r-1 SO r-l 5^1 
 
 SKSSfefe 
 
 ^- -t c: oo <D 
 
 v " <r- 9- r- ?> 
 
 inn 
 
 j o ft 
 
 CO ^ 
 
 > >. 
 
 ji 
 
 *Winter Sal 
 *Winter Sal 
 
 
 
 CC Oj CO O 
 
 cb co co co 
 
 SSSfeS 
 SSSS^ 
 
 !
 
 of the Salmon in Fresh Water. 
 
 123 
 
 I I <??? 
 
 -* I cocb 
 
 
 F-H CO CO CO (N CO 
 
 O1IO CO CO CO CO 
 
 
 O O 1C l^ 
 
 ~f -^ O O V 
 
 (MCO "* r?C 
 
 ) OD O 
 
 .^ r^ 
 
 3SS 
 
 CO (N O 
 
 IO C*"> 7 1 
 
 (MCOCO ' CO 
 
 ccco <ico 
 
 
 r-4 -^t* ^ i i -^ o 
 Oi O OO UTi t^. -^ CO 
 
 
 opoo o 
 
 * T? '~ rr '-O oo t-^. 
 An O o 6i ^ Oi i>. 
 
 ^t* ?D O-l C^ ( C^J >O 
 
 l-H 1-- l^. i 1 O O OC 
 
 ^ CO CO -^ CO Tt^ ^ 
 
 iiniii 
 
 sllis 
 
 WWPWKWQ
 
 124 
 
 Investigations on the Life,- History 
 
 From the foregoing Tables 1 and 2, the following shorter Tables are 
 constructed. In them the total nitrogen of the muscle and of the ovaries 
 is expressed, not as the total ot the individual fish, but for purposes of 
 comparison as the total of the fish of standard length (vide page 6). 
 
 TABLE III. 
 
 Showing Amount of Nitrogen per Fish of Standard Length in 
 Muscle and Ovaries. 
 
 FEMALE ESTI T ARY FISH, 1896. 
 May and June. 
 
 
 Muscle. 
 
 Ovaries. 
 
 No. 
 
 Thick. 
 N. 
 per Cent. 
 
 Thin. 
 X. 
 per Cent. 
 
 N. Total 
 per Fish 
 of Stndrd 
 Length. 
 
 N. 
 per Cent. 
 
 N. 
 per Fish 
 of Stndrd 
 Length. 
 
 16 
 20 
 25 
 27 
 
 Average, 
 
 3-80 
 3-25 
 3-29 
 3-25 
 
 3-18 
 2-91 
 3-02 
 3-05 
 
 218 
 219 
 209 
 201 
 
 3-01 
 3-16 
 3-24 
 3-35 
 
 2-85 
 4-55 
 5-50 
 4-92 
 
 3-40 
 
 :5-04 
 
 210 
 
 3-19 
 
 4-45 
 
 Juli/ and August. 
 
 36 
 
 3-75 
 
 3-31 
 
 211 
 
 3-80 
 
 10-10 
 
 40 
 
 3-31 
 
 2-95 
 
 225 
 
 3-06 
 
 3-03 
 
 45 
 
 3-02 
 
 2-90 
 
 188 
 
 2-98 
 
 4-60 
 
 51 
 
 3-56 
 
 3-18 
 
 238 
 
 3-35 
 
 6-50 
 
 55 
 
 3-96 
 
 3-06 
 
 228 
 
 3-62 
 
 10-70 
 
 Average, 
 
 3-52 
 
 3-08 
 
 218 
 
 3-36 
 
 7* 
 
 
 
 
 
 i 
 
 October and Xovembw. 
 
 65 
 73 
 
 74 
 
 Average, 
 
 2-93 
 
 2-93 
 
 213 
 
 4-07 
 
 63-5 
 
 3-43 
 
 3-48 
 
 206 
 
 4-12 
 
 65-5 
 
 3-52 
 
 3-44 
 
 208 
 
 3-26 
 
 42-7 
 
 3-29 
 
 3-28 
 
 209 
 
 3-82 
 
 57-2
 
 of the Salmon in Fresh \\ r ater. 
 TABLE IV. 
 
 125 
 
 Showing Amount of Nitrogen per Fish of Standard Length in Muscle 
 and Ovaries. 
 
 FEMALE UPPER WATER FISH, 1896. 
 May and June. 
 
 No. 
 
 Muscle. 
 
 Ovaries. 
 
 Thick. 
 
 Thin. 
 
 N. Total 
 per Fish 
 of Stndrd 
 Length. 
 
 N. 
 per Cent. 
 
 N. Total 
 per Fish 
 of Stndrd 
 Length. 
 
 12 
 21 
 31 
 32 
 
 Average, . 
 
 3-44 
 3-41 
 3-28 
 3-32 
 
 3-68 
 3-25 
 2-98 
 3-35 
 
 195 
 206 
 174 
 178 
 
 2-85 
 2-93 
 2-64 
 3-46 
 
 3-85 
 6-47 
 7-95 
 14-36 
 
 3-38 
 
 3-31 
 
 188 
 
 2-97 
 
 8-16 
 
 June and July. 
 
 37 
 
 3-20 
 
 2-89 
 
 165 
 
 3-69 
 
 12-8 
 
 42 
 
 3-50 
 
 3-13 
 
 197 
 
 4-11 
 
 23-4 
 
 43 
 
 3-22 
 
 3-07 
 
 172 
 
 3-55 
 
 12-7 
 
 49 
 
 3-34 
 
 3-03 
 
 205 
 
 3-79 
 
 17-4 
 
 erage, 
 
 3-32 
 
 3-03 
 
 185 
 
 3-78 
 
 16-6 
 
 
 
 I 
 
 
 
 October and November. 
 
 62 
 
 2-89 
 
 2-65 - 
 
 123 
 
 4-01 
 
 81-4 
 
 63 
 
 2-82 
 
 2-76 
 
 104 
 
 4-14 
 
 76-6 
 
 64 
 
 2-99 
 
 2-87 
 
 134 
 
 4-30 
 
 90-7 
 
 66 
 
 2-54 
 
 2-20 
 
 107 
 
 4-33 
 
 94-0 
 
 67 
 
 2-70 
 
 2-54 
 
 103 
 
 4-05 
 
 81-8 
 
 69 
 
 2-82 
 
 2-45 
 
 108 
 
 2-68 
 
 99-7 
 
 70 
 
 2-88 
 
 2-73 
 
 113 
 
 2-83 
 
 78-5 
 
 Average, . 
 
 2-81 
 
 2-6 
 
 113 
 
 4-05 
 
 86-1 
 
 In considering the observations shown in the foregoing Tables, I shall 
 first take up the condition of the muscle as shown by the percentage of 
 uitrogen contained ; then the total amount of muscle proteid in the fish 
 of standard length as shown by the amount of nitrogen ; then consider
 
 126 
 
 Investigations on the Life-History 
 
 the ovaries in a similar manner ; and lastly, consider the inferences that 
 may be drawn from the changes observed. 
 
 /. Percentage of Proteid in Muscle. Two samples of muscle from each 
 fish were examined, one from the under part of the fish (thin), the other 
 from the dorsal part (thick). It will be observed in the tables that the 
 "thick" muscle is, at all seasons, and in both estuary and upper- water fish, 
 richer in nitrogen than the " thin " muscle. This difference in the amount 
 of nitrogen, and consequently in the amount of proteid, emphasises the 
 importance of analysing both portions of the musculature as already 
 noted (p. 80). The smaller percentage of proteid in the thin muscle is 
 probably dependent on the larger percentage of fat there (vide p. 83), 
 the fat of course increasing the weight reduces the percentage of other 
 constituents present. 
 
 The amount of proteid of the muscle in estuary fish is fairly constant 
 throughout the season. It is slightly higher in July and August than 
 in May and June, and slightly lower in October and November than in 
 the earlier months. The fish which show the greatest divergence from 
 the average are Nos. 72 and 79. These fish were caught in the estuary 
 late in the year (winter salmon), had undeveloped ovaries, and would not 
 spawn till the following year. Their muscles were laden with fat, and 
 consequently the percentage of proteid was lower than the average. 
 
 The muscles of the upper- water fish show more change. Those of the 
 fish caught in October and November have a much smaller amount of 
 proteid than the earlier fish. This percentage diminution is not due to 
 increase of fat, as in 72 and 79, the amount of fat being diminished, but 
 is due to an increase in the water of the muscle (page 84). The upper- 
 water fish from May to August have a fairly constant percentage of 
 proteid, and that percentage is nearly the same as in estuary fish 
 throughout the series. 
 
 TABLE V. 
 
 Showing the percentage of nitrogen in the muscle of the different 
 groups of fish : 
 
 
 Estuary. 
 
 Upper Water. 
 
 
 Thick. 
 
 Thin. 
 
 Thick. 
 
 Thin. 
 
 May and June 
 
 3-40 
 
 3-04 
 
 3-38 
 
 3-31 
 
 July and August - 
 
 3-52 
 
 3-08 
 
 3-32 
 
 3-03 
 
 October and November - 
 
 3-29 
 
 3-28 
 
 2-81 
 
 2-60 
 
 //. Total Muscle Proteid of the Fish. In considering this point two 
 comparisons suggest themselves. Firstly, comparing the muscles of the 
 fish of the later periods of the year with the earlier ones; and, 
 secondly, comparing the muscles of the upper- water fish with those of 
 the estuary fish. 
 
 The estuary fish, as is seen in Table III, have a nearly constant 
 amount of muscle nitrogen throughout the season, the aveiage for the
 
 of the Salmon in Fresh Water. 
 
 127 
 
 three periods being 210, 218, and 209 grammes of nitrogen in the fish 
 of standard length, the average for the year being 213. Some excep- 
 tions to this were observed, notably Fish 15, 17, 29 (vide Table 1), the 
 nitrogen of these amounting to only 196, 177, and 177 grammes per 
 fish of standard length. Nos. 29 and 1 7 were exceptional in other ways. 
 No. 29 had wounds on its side, No. 1 7 had an empty gall bladder, but 
 about No. 15 nothing abnormal is noted. 
 
 The upper- water fish show marked changes in the amount of muscle 
 nitrogen, the amount decreasing as the season advances, the decrease 
 being much more marked in the later part of the season. The amount 
 of aitrogen per fish of standard length was in May and June 188 grms., 
 in July and August 185 grms., in October and November only 113 
 grms. 
 
 The large fall of the amount of muscle nitrogen in October and 
 November will be considered after the gain of nitrogen by the ovaries 
 has been discussed. 
 
 A comparison of the upper-water fish with those of the estuary shows 
 that all through the year the upper-water fish have less muscle nitrogen 
 than the estuary fish, the deficit being greatest in October and 
 November. 
 
 ///. Percentage of Proteids in the Ovaries. An examination of the 
 figures given in Tables 1 and 2 shows that there is throughout the 
 season a steadily increasing percentage of proteid matter in the ovaries, 
 both in estuary and in upper- water fish. In estuary fish the amount of 
 nitrogen in the ovaries rises from 3'19 per cent in May and June to 3'36 
 per cent in July and August, and 3'82 per cent in October and 
 November. In the upper-water fish the corresponding figures are 2-97 
 per cent, 3*78 per cent, and 4'05 per cent. 
 
 IV. Total Proteids of the Ovaries This also shows a steady increase 
 during the season ; not only are the ovaries richer in nitrogen as the 
 season advances, as stated above, but they are increasing in weight 
 the whole time. The increase of proteid takes place both in estuary 
 and in upper-water fish, but it is greater in the upper water fish. 
 These changes are shown in the following table. 
 
 TABLE VI. 
 
 Showing amount of ovarian nitrogen per cent, and in fish of standard 
 length : 
 
 
 May and June. 
 
 July and August. 
 
 Oct. and Nov. 
 
 
 Estuary. 
 
 Upper 
 Water. 
 
 Estuary. 
 
 wE 
 
 Estuary. 
 
 wE 
 
 Nitrogen per cent. . 
 
 3-19 
 
 2-97 
 
 3-36 
 
 3-78 
 
 3-82 
 
 4-05 
 
 Nitrogen per fish of 
 standard length . 
 
 4-45 
 
 8-16 
 
 7-0 
 
 16-6 
 
 57-2 
 
 86-1 
 
 Comparing this Table with that referring to the total amount of 
 muscle nitrogen during the three periods, it is evident that it is during 
 the time of the greatest ovarian increase that the muscle loses most. 
 
 A comparison between the loss of proteid from muscle and the gain of 
 proteid by ovaries, when the salmon is in fresh water, is shown in the 
 following table, the fish being compared with each other in the manner 
 adopted by Dr. Paton (p. 81).
 
 128 
 
 Investigations on the, Life-History 
 TABLE VII. 
 
 Showing balance of nitrogen between muscle and ovaries per fish of 
 standard length: 
 
 Date and Source of 
 Fish. 
 
 Average 
 Muscle 
 Nitrogen. 
 
 Loss from 
 Muscle. 
 
 Average 
 Ovary 
 Nitrogen. 
 
 Gain by 
 Ovaries. 
 
 Surplus Loss 
 from Muscle 
 available for 
 Energy, &c. 
 
 May to August 
 Estuary, . 
 
 214 
 
 _ 
 
 5-7 
 
 
 
 July to August- 
 Upper Water, 
 
 185 
 
 29 
 
 12-4 
 
 6-7 
 
 22 
 
 May to August- - 
 Estuary, . . ,- : 
 
 214 
 
 
 
 5-7 
 
 
 _ 
 
 October to November 
 Upper Water, 
 
 113 
 
 101 
 
 86-0 
 
 80-3 
 
 20 
 
 These balances clearly show that the amount of proteid lost from the 
 muscle is ample to supply the wants of the growing ovaries, as in each 
 case the loss from the muscle is greater than the gain by the 
 ovaries. As previously stated, the surplus loss may be considered as 
 showing that there is a consumption of proteid to meet the other 
 requirements the production of energy and the repair of energy-pro- 
 ducing mechanism. It will be seen that this surplus loss amounts in 
 each instance to a very considerable quantity in one case to 22 grammes 
 of nitrogen per fish of standard length, in the other to 20 grammes. 
 
 Twenty-two grammes of nitrogen are equivalent of 1 37'5 grammes of 
 proteid, the energy value of which is 560 large calories or 240,000 
 kilogramme-metres, an amount of energy sufficient to raise a fish of 
 standard length weighing 10 kilogrammes to a height of 2 4, 000 metres 
 (or 78,000 feet). Similar calculation shows the other suiplus loss has 
 an energy value of 2 1 7,000 kilogramme-metres, and is sufficient to raise 
 a fish of standard length to a height of 21,700 metres (or 71,000 feet). 
 
 V. Conclusions. The inferences to be drawn from this examination 
 of the female fish of 1896 may be summed up as follows : 
 
 1. Estuary fish have more muscle proteid than upper- water fish. 
 
 2. The amount of muscle proteid in the upper-water fish diminishes 
 as the season advances. The October and November upper-water 
 fish are very poor in muscle proteid, having little more than half the 
 amount of muscle proteid that estuary fish have. 
 
 3. The ovaries of both estuary and upper- water fish gain proteid as 
 the season advances. 
 
 4. The estuary fish and the upper-water fish of the early months have 
 sufficient proteid in the musculature to supply the wants of the growing 
 ovaries, and from the deficit of muscle proteid found in the late upper- 
 water fish, it is probable that there is a transference of proteid from the 
 musculature to the ovaries. 
 
 5. The deficit of muscle proteid in upper water fish is so large that 
 after allowing for the requirements of the ovaries there remains a surplus 
 loss. This surplus loss is available for the liberation of a large amount 
 of energy. 
 
 MALE FISH, 1896. 
 
 The examination of the male fish received during 1896 corroborates 
 the results obtained from the examination of the female fish of that
 
 of the Salmon in Fresh Water. 
 
 129 
 
 year. Though the number received and examined was somewhat small, 
 it was sufficiently large to show that the male fish ore affected by their 
 stay in fresh water in exactly the same way as the female fish. 
 
 The results of the observations are shown in the following Tables : 
 
 
 
 1 
 
 r 
 
 
 
 y 
 
 s 
 
 4J 
 
 
 
 I 
 
 00 
 
 1 
 
 1 
 
 a 
 
 +J 
 
 
 
 i 
 
 p 
 
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 825 , 
 
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 s 
 
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 IN 
 
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 ^ 
 
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 s 
 
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 1 
 
 1 

 
 130 
 
 Investigations on the Life-History 
 
 Remarks. 
 
 
 1 
 
 55 
 
 ? 
 
 S-S 
 
 55* 
 
 CO 
 <N 
 
 1 
 
 s 
 
 4 
 
 I 
 
 55 
 
 oo 
 
 s 
 
 1 
 
 I 
 
 1 
 
 55' 
 
 I 
 
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 9 
 
 CO 
 
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 CO 
 
 ' 
 
 55' 
 
 1 
 
 55 
 
 T 
 
 CO 
 
 1 
 
 I 
 
 | 
 
 s 
 
 a 
 
 1 
 
 1 
 
 a
 
 q/ the Salmon in Fresh Water. 131 
 
 TABLE X. 
 
 SHOWING PER FISH OF STANDARD LENGTH THE AMOUNT OF NITROGEN 
 
 IN MUSCLE AND TESTES IN MALE ESTUARY FISH, 1896. 
 
 MAY AND JUNE. 
 
 No. 
 
 Muscle. 
 
 Testes. 
 
 Thick. 
 N. % 
 
 Thin. 
 
 ,N. % 
 
 N. per Fish 
 of Standard 
 Length. 
 
 N. % 
 
 N. per Fish 
 of Standard 
 Length. 
 
 19 
 
 Average, . 
 
 3-2 
 
 2-82 
 
 174 
 
 3-29 
 
 0-51 
 
 3-2 
 
 2-82 
 
 174 
 
 3-29 
 
 0-51 
 
 JULY AND AUGUST. 
 
 56 
 
 3-32 
 
 2-88 
 
 222 
 
 1-87 
 
 0-37 
 
 59 
 
 3-39 
 
 3-04 
 
 231 
 
 2-16 
 
 0-78 
 
 61 
 
 3-70 
 
 2-23 
 
 181 
 
 2-58 
 
 1-95 
 
 Average, . 
 
 3-47 
 
 2-72 
 
 211 
 
 2-20 
 
 1-03 
 
 OCTOBER AND NOVEMBER. 
 
 71 
 
 75 
 
 Average, . 
 
 3-22 
 3-33 
 
 2-86 
 3-03 
 
 209 
 172 
 
 4-16 
 4-02 
 
 8-84 
 12-27 
 
 3-28 
 
 2-95 
 
 190 
 
 4-09 
 
 10-55 
 
 TABLE XI. 
 
 SHOWING PER FISH OF STANDARD LENGTH THE AMOUNT OF NITROGEN 
 
 IN MUSCLE AND TESTES IN MALE UPPER-WATER FISH, 1896. 
 
 MAY AND JUNE. 
 
 No. 
 
 Muscle. 
 
 Testes. 
 
 Thick. 
 
 N- % 
 
 Thin. 
 
 N.% 
 
 N. per Fish 
 of Standard 
 Length. 
 
 N.% 
 
 N. per Fish 
 of Standard 
 Length. 
 
 34 
 
 Average, . 
 
 3-26 
 
 3-01 
 
 168 
 
 2-13 
 
 0-94 
 
 3-26 
 
 3-01 
 
 168 
 
 2-13 
 
 0-94 
 
 JULY AND AUGUST. 
 
 38 
 
 3-50 
 
 3-31 
 
 206 
 
 1-91 
 
 85 
 
 39 
 
 3-26 
 
 2-85 
 
 167 
 
 1-88 
 
 1-81 
 
 54 
 
 3-65 
 
 ,3-31 
 
 167 
 
 2-32 
 
 4-75 
 
 verage, . 
 
 3-47 
 
 3-16 
 
 180 
 
 2-04 
 
 247
 
 132 
 
 TABLE XI. -Continued. 
 OCTOBER AND NOVEMBER. 
 
 Average, 
 
 2-78 
 2-78 
 
 2-47 
 2-47 
 
 114 
 
 3-43 
 
 9-23 
 
 114 
 
 3-43 
 
 9-23 
 
 These Tables show the following facts about the male salmon : 
 
 1. In all the groups of fish the thick muscle contains more proteid 
 than the thin, 
 
 2. The upper-water tish have a smaller percentage of nitrogen in 
 their muscle than the estuary fish. 
 
 3. The total amount of proteid in the musculature is less in upper- 
 water fish than in estuary fish, the upper-water fish of October and 
 November being especially poor. 
 
 4. The testes become richer in nitrogen as the season advances. 
 
 5. The total proteid of the testes is greater as the season advances. 
 
 G. The loss of proteid from the muscle is greater than the gain by 
 the testes, there being a surplus loss available for the production of 
 energy and processes of repair. 
 
 This surplus loss is much greater than in female fish, and con- 
 sequently a much larger amount is available for energy. 
 
 The changes being exactly comparable to those observed in female 
 salmon, it may be concluded that male salmon, like female salmon, 
 have sufficient proteid stored in their muscles to meet all their require- 
 ments in fresh water, and that this proteid is called on to supply the 
 wants of the growing testes, and for the liberation of energy. 
 
 SALMON OF 1895. 
 
 The small number of fish available for analysis prevents averages 
 being struck arid accurate comparisons being made. The results 
 obtained, and to be seen in Tables 12, 13, 14, and 15 show that the 
 amounts of proteid in the muscle and genitalia of these fish vary withir 
 the same limits as were found in the 1896 fish. No notes are available 
 as to whether the fish included in these Tables are fresh run or havt 
 been in fresh water for some time, but by comparing the amount of muscle 
 nitrogen per fish of standard length with that of the 1896 fish they can 
 be readily classified. Thus 31, 19, and 40 are evidently fresh run, as 
 their muscle contains as much nitrogen as the muscle of the fresh run 
 1896 fish of the corresponding periods, and 29, 39, and 43 are evidenth 
 fish which have been in fresh water for some time, their musculature 
 being in the condition found in upper- water fish of 1896 of thf 
 corresponding periods. The condition of the genitalia corroborates tVm 
 contention. 
 
 [TABLE
 
 Water. 
 
 133 
 
 1 1 
 
 s s 
 
 "S 'S 
 
 ^t) 
 
 
 ow
 
 134 
 
 Investigations on the JAfe History 
 
 
 
 
 . . c 
 
 
 
 
 
 
 
 
 CCS 
 
 
 
 
 
 
 
 
 11^ 
 
 
 
 
 
 
 
 . 
 
 111 
 
 C CM 
 
 s = ^ 
 
 
 
 
 
 
 
 I 
 
 3 "0*0 
 
 
 
 
 
 
 
 S3 
 
 .. ;A +J 
 
 
 
 
 
 
 
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 SS.SP 
 
 s^g 
 
 
 
 
 
 
 
 
 Ilil 
 
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 of the Salmon in Fresh Water. 
 
 135 
 
 TABLE XIV. 
 
 SHOWING AMOUNT OF NITROGEN PER FISH OF STANDARD LENGTH IN 
 MUSCLE AND OVARIES OF FEMALE FISH, 1895. 
 
 Muscle. 
 
 Ovaries. 
 
 No. 
 
 Thick. 
 N. %. 
 
 Thin. 
 
 N. %. 
 
 Total per Fish 
 of Standard 
 Length. 
 
 N. %. 
 
 N. per Fish 
 of Standard 
 Length. 
 
 MAY AND JUNE. 
 
 2 
 
 3-52 
 
 2-67 
 
 - 
 
 2-52 
 
 - 
 
 JULY AND AUGUST. 
 
 8 
 10 
 23 
 
 4-05 
 3-55 
 3-64 
 
 3-12 
 2-74 
 3-26 
 
 197 
 
 1-27 
 3-73 
 1-41 
 
 18-5 
 
 OCTOBER, NOVEMBER, AND DECEMBER. 
 
 27 
 31 
 29 
 39 
 
 2-77 
 3-35 
 2-46 
 2-65 
 
 2-64 
 
 2-86 
 2-05 
 2-67 
 
 215 
 144 
 114 
 
 2-72 
 
 4-02 
 4-09 
 Lost. 
 
 48-3 
 29-5 
 
 TABLE XV. 
 
 SHOWING PER FISH OF STANDARD LENGTH THE AMOUNT OF NITROGEN 
 IN MALE FISH, 1895. 
 
 MAY AND JUNE. 
 
 
 Muscle. 
 
 Testes. 
 
 No. 
 
 Thick. 
 N.%. 
 
 Thin. 
 
 N.%. 
 
 N. per Fish 
 of Standard 
 Length. 
 
 N.%. 
 
 N. per Fish 
 of Standard 
 Length. 
 
 4 
 
 3-17 
 
 3-60 
 
 
 2-02 
 
 _ 
 
 5 
 
 3-00 
 
 3-25 
 
 _ 
 
 2-09 
 
 
 6 
 
 3-49 
 
 3-10 
 
 - 
 
 3-12 
 
 " 
 
 JULY AND AUGUST. 
 
 19 
 
 3-23 
 
 2-83 
 
 224 
 
 1-48 
 
 ro 
 
 OCTOBER AND NOVEMBER. 
 
 40 
 43 
 
 3-10 
 2-41 
 
 2-38 
 2-55 
 
 198 
 104 
 
 2.81 
 2-44 
 
 9-5 
 5-6 
 
 KELTS. 
 
 In the following Tables will be seen the results obtained from the 
 analyses of kelts. One was received in 1895, the others early in 
 1897.
 
 136 
 
 Investigations on the Lije-History 
 
 CS <N 00 
 ^1 CD CO 
 
 I-- !N W 
 
 k 3 8 S 
 
 00 M OJ ^. 
 
 ^ c5 ?3 01 
 
 IM t- 
 
 071 OJ (fj tN 
 
 S S S
 
 of the Salmon in Fresh 
 
 137 
 
 TABLE XVII. 
 
 SHOWING NITROGEN PEK CENT. AND PER FISH OF STANDARD LENGTH 
 IN KELTS, 1895 AND 1890. 
 
 
 Muscle. 
 
 
 
 No. 
 
 
 Total N. 
 
 
 Thick. 
 
 N. % 
 
 Thin. 
 
 N. % 
 
 i per Fish of M 0/ 
 Standard 
 
 
 
 
 Length. 
 
 14 
 
 3-18 
 
 2-93 
 
 
 1-87 
 
 80 
 
 2-95 2-84 
 
 135 
 
 1-62 
 
 81 
 
 2-91 2-72 
 
 142 
 
 1-70 
 
 82 2-90 277 
 
 138 1-67 
 
 83 2-76 2-54 
 
 96 1-39 
 
 Ovariet 
 
 Total N. 
 
 per Fish of 
 
 Standard 
 
 Length. 
 
 71 
 
 1-35 
 9 
 
 TABLE XVIII. 
 COMPARING KELTS WITH UNSPAWNED FISH. 
 
 ( 
 
 Thick, N. %, . 
 
 Unspawned Fish. 
 
 
 Estuary. 
 
 Upper Water. 
 
 July and 
 
 August. 
 
 October & 
 November. 
 
 3-40 
 
 3-32 
 
 2-81 
 
 uscle, -I 
 
 Thin, N. %, . . 
 
 3-13 
 
 3-03 
 
 2-60 
 
 
 1 
 
 N. per Fish of 
 Standard Length 
 
 J212 
 
 185 
 
 113 
 
 1 
 
 varies, -1 
 
 N. %, . . . 
 
 N. per Fish of 
 Standard Length 
 
 3-46 
 j 4-45 57-2 
 
 3-78 
 16-6 
 
 4-05 
 86-1 
 
 
 Kelt. 
 
 2-94 
 2-74 
 
 128 
 
 1-64 
 0-9 
 
 A comparison of these results with those of the female unspawned 
 fish of 1896 shows the following : 
 
 1. The muscle of the kelt contains a smaller percentage of proteid 
 than all the unspawned fish except those from the upper waters late in 
 year. 
 
 2. The total amount of muscle nitrogen per fish of standard length 
 is less than that of the unspawned fish, the same late upper- water 
 unspawned fish being excepted. 
 
 3. The percentage of proteid in the ovary is less than in all unspawnod 
 fish. 
 
 1. The total nitrogen per fish of standard length in the ovary is less 
 than in all unspawned fish. 
 
 It will be seen in the Tables that out of the four fully analysed kelts 
 three have more nitrogen in their muscle than the upper-water fish of tl 
 later months of the year. There are two explanations of this, the one 
 that they represent not the late upper-water fish, but the late estuary
 
 138 Investigations on the Life- History 
 
 fish ; the other, that there has been a retransference of proteid from 
 the ovary to the muscle. Both these are feasible, but the former is 
 probable, from the fact that the size of the fish corresponds, not with 
 the upper-water fish of October and November, but with the estuary 
 fish of these months. The fourth examined kelt has so little muscle 
 nitrogen, only 96 grms. per fish of standard length, that it might- 
 be considered to represent a late upper-water fish ; the other three, 
 averaging 138 grins., might represent the late estuary fish. On the 
 other hand, the loss from the ovaries in and after spawning is so much 
 greater than the gain by the muscle, that it is po.-sible that some of 
 this proteid may have been transferred ; but, as no measure of the loss 
 in ova is available, it cannot be stated how much ovarian proteid 
 remained to be retransferred to the muscles. 
 
 THE CARBOHYDRATES OF THE SALMON. 
 NOTE BY D. NOEL PATON, M.D. 
 
 In the present investigations the Carbohydrates have not been 
 studied. They are very briefly considered by Miescher (Histochemischen 
 and Physiologischen Arbeiten 1897, Bd. II., s. 325). He finds that 
 sugar is present in the blood and liver and glycogen in the muscles and 
 liver, though in small amounts, even when the salmon has been long in 
 the river.
 
 of the Salmon, in Fresh \Y<tter. 
 
 139 
 
 12. THE FATS AND PROTEIDS STORED IN THE 
 MUSCLE CONSIDERED AS A SOURCE OF 
 MUSCULAR ENERGY. 
 
 BY D. NOEL PATON, M.I). F.R.C.P.ED. 
 
 The foregoing study of the changes in the fats and proteids affords a 
 basis for the elucidation of the part played by each of these in the 
 liberation of energy available for the muscular work of the fish. 
 
 The fats and proteids lost from the muscles during the sojourn of the 
 fish in fresh water, over and above those accumulated in the ovaries and 
 testes, must be decomposed for the liberation of energy. 
 
 This matter is of interest, firstly, because it shows whether the energy 
 evolved from the fats and proteids decomposed is ad equate for the needs 
 of fish during its stay in fresh water ; and, secondly, because it elucidates 
 the question, not hitherto studied by physiologists, of the source of the 
 energy in cold-blooded animals. 
 
 The following Table shows the amount of energy in work units 
 Kilogrammebres set free from each of these substances throughout the 
 season. In these Tables the fats and the nitrogen are given in 
 grms. : 
 
 FEMALE SALMON 1896. 
 Fat Balance per Fish of Standard Length. 
 
 Estuary (May to August), 
 Upper Water (July and A 
 
 August) 
 
 Muscle. 
 
 770 
 478 
 
 Loss 292 
 
 Ovaries. 
 
 Gain 31 
 
 Available for liberation of energy, 261 grms. = 1,025,730 Kgms. 
 
 To this should be added about 20 grms. of fat from the pyloric 
 appendages ; and about 20 grms. of fat from the liver (see p. 100J, say 
 40 : which makes 300 grms., or 1,179,000 kgms. 
 
 tuary (May to August), 
 pper Water (Oct. and Nov.), 
 
 Muscle. 
 
 Ovaries. 
 
 770 
 159 
 
 15 
 
 204 
 
 Loss 611 
 
 Gain 189 
 
 Available for liberation of energy, 422 grms. ? 1,658,460 Kgms.
 
 140 Investigations on the Lifo- Ifi 
 
 Nitrogen Balinc*. per Fish of Standard 
 
 Estuary (May to August), 
 Upper Water (July and August) 
 
 Muscle. 
 
 Ovaries. 
 
 214 
 185 
 
 5-7 
 12-4 
 
 Loss 29 
 
 Gain 6-7 
 
 Available for liberation of energy, 22 grms. = 240,000 Kgrns. 
 
 Muscle. Ovaries. 
 
 Estuary (May to August), . 214 
 
 Upper Water (Oct. and Nov.). 1 
 
 214 
 113 
 
 5-7 
 86-0 
 
 Loss- 101 
 
 Gain 80-3 
 
 Available for liberation of energy, 20 grms. 217, Odd Kgms. 
 
 MALE SALMON 1896. 
 
 The number of male fish analysed is too small to allow of any good 
 average being struck as i-egnrds the amount of material available fov the 
 evolution of energy. Especially is this the case as regards the later part 
 of the season, since only one male fish from the upper waters was 
 obtained in October and November. 
 
 In the earlier part of the season the evolution of energy appears about 
 the same in the male as in the female. 
 
 TABLE 
 Fat Balance per Fish of Standa/rd Length. 
 
 Estuary (M ay to August), 
 Upper Water (July and August) 
 
 Muscle. 
 
 756 
 428 
 
 Loss- 328 
 
 Testes. 
 
 0-74 
 2-41 
 
 Gain 1-67 
 
 Available for liberation of energy, 326 grms. = 1,271,400 Kgrus. 
 
 Muscle. 
 
 Testes. 
 
 Estuary (May to August), 
 Upper Water (Oct. and Nov), | 
 
 756 
 103 
 
 0-74 
 6-34 
 
 Loss 653 
 
 I Gain 5 '60 
 
 Available for liberation of energy, G47 grms. 2.523,300 Kiriu?
 
 of the /Salmon in Fresh Water. 
 Nitrogen Balance per Fish of Standard Length. 
 
 141 
 
 Estuary (May to August), 
 Upper Water (July and August) 
 
 Muscle. 
 
 Testis. 
 
 192 
 
 180 
 
 077 
 2-47 
 
 Loss 12 
 
 Gain 1-70 
 
 Available for liberation of energy, 10 grms. = 109,000 Kgms. 
 
 Estuary (May to August) 
 Upper Water (Oct. and Nov.), 
 
 Muscle. 
 
 Testis. 
 
 192 
 114 
 
 0-77 
 9-23 
 
 Loss 78 
 
 Gain 8-46 
 
 Available for liberation of energy, 70 grms. = 763,000 Kgms. 
 
 FEMALE FISH. 
 
 To August Kgms. 
 
 Energy liberated from fats, . . . 1,025,730 
 Energy liberated from proteids, . . 240,000 
 Energy from proteids to energy from fats, as 1 : 4-2.* 
 
 To November Kgms. 
 
 Energy liberated from fats, . . '. 1,658,460 
 Energy liberated from proteids, . . 217,000 
 Energy from proteids to energy from fats, as 1 : 7'6. 
 
 MALE FJSH. 
 
 To August Kgms. 
 
 Energy liberated from -fats, . . . 1.271,400 
 Energy liberated from proteids, . . 109,000 
 Energy from proteids to energy from fats, as 1 : 11 -6 
 
 These Tables bring out several points of very great interest. 
 
 1 Of the fats lost from the muscle of female fish to August, only a 
 very small moiety 12per cent. goes to the ovaries, the remaining 88 per 
 cent, is available as a source of energy. Taking the metabolism 
 to November, 30 per cent, of the fats go to the ovary and 70 to energy. 
 
 2. Of the proteids lost from the muscle to July and August in the 
 female, 23 per cent, are transferred to the ovaries, 77 per cent, are avail- 
 able for energy ; but later in the season the pro^eid lost from the muscle 
 is almost entirely transferred to and built up in the growing ovaries, 
 little or none being available for muscular energy. 
 
 3. It thus follows that while in the earlier months the energy of 
 muscular work is derived from the fats to the extent of 8 1 per cent., 
 and from proteids to the extent of 19 per cent., during the later 
 months the fats are almost the sole source of energy. 
 
 *If the internal fats are also considered the proportion will be 1 to 4 '9.
 
 142 
 
 Investigations on the Life-History 
 
 4. In the male, of the fats lost from the muscle to August, 5 percent, 
 are accumulated in the testes, while 95 per cent, are available for energy. 
 Of the proteids 14 per cent, go to the testes, leaving 86 per cent, 
 as a source of energy. 
 
 5. In the period to August, when male and female fish can be compared, 
 the energy liberated per fish of standard length was, in the female, 
 equivalent to 1,205,000 Kgms.,* while in the male it was equivalent to 
 1,380,000 Kgms. In the female, where fat accumulation in the ovaries is 
 large, a greater proportion of energy appears to be derived from the pro- 
 teids of the muscle than in the male, where the testes is comparatively 
 poor in fats. Here the fats of the muscle yield a larger proportion of 
 energy than in the female. In the female to August, of the total 
 available energy, about 20 per cent, is derived from the proteids, while 
 in the male only 9 per cent, is obtained from this source. 
 
 In ascending the river the salmon has not only to raise its weight to 
 a given height, but it has to overcome the friction of the stream. 
 
 The former factor in the expenditure of energy is easily calculated if 
 the elevation of the upper waters of the river is known. 
 
 The following Table gives the elevation of the upper waters of the 
 three rivers, and the work done in raising a fish of standard length 
 and average weight 10 Kg.s. 
 
 Dee - 
 
 Spey 
 
 Average, 
 
 Height in Metres. 
 
 Work Done in 
 Kgms. 
 
 Energy Evolved 
 from Fats and 
 Proteids to August 
 in Female Fish. 
 
 1,266,000 
 
 225 
 216 
 
 2250 
 2160 
 
 220 
 
 2205 
 
 1,266,000 
 
 The energy employed in merely lifting the weight of the fish is to the 
 whole energy expended as 1 to 570. 
 
 An enormous surplus of energy is thus available for the work of 
 overcoming friction. To form anything like a correct idea of what this 
 may be is at present impossible, for information as regards the rate of 
 progress of salmon is wanting, and the work done by the fish will 
 necessarily vary with the rate at which the upward progress is made. 
 
 But these figures show that for this work an enormous surplus of 
 energy is available from the combustion of the fats and proteids which 
 disappear from the muscles throughout the sojourn of the fish in fresh 
 water. 
 
 Pfliiger has recently (Pflttg. Arch. Bd., XLVI.) most strenuously 
 maintained the view that the proteids are the great source of the energy 
 for muscular work. The present observations very clearly prove that, 
 in a cold-blooded animal, fats are a source of energy, and that they play a 
 much more important part than the proteids. 
 
 * The Kilogram met.re is the work done 
 equivalent to 7'24 foot-pounds. 
 
 in lifting a Kilogramme through one metre. It is
 
 of the Salmon in Fresh Water. 143 
 
 13. THE PHOSPHORUS COMPOUNDS OF THE MUSCLE 
 AND GENITALIA OF THE SALMON, AND 
 THEIR EXCHANGES. 
 
 BY D. NOEL PATON, M.D. F.R.C.P. ED. 
 
 Phosphorus forms an essential constituent of every living creature, 
 and in the higher animals it is very widely distributed in the different 
 tissues in various combinations. In the bones and other tissues it 
 occurs as inorganic phosphates, possibly in loose organic combination. 
 It also occurs as stored nutrient material in the yolk of the egg in at 
 least two forms (a) as pseiido-nucleins, substances yielding a proteid 
 and phosphoric acid when split, and (b) as lecithin in which a molecule 
 of the fatty acid radicle of a glycerine fat is replaced by phosphoric acid 
 linked to a peculiar nitrogenous base, cholin. Lastly, in protoplasm, 
 and more especially in the nucleus of the cells, it occurs in nnclein com- 
 pounds compounds in which a proteid is linked to nucleic acid a 
 substance which, on being broken down, yields phosphoric acid and 
 various nitrogenous bases such as xanthin. 
 
 The most complex of these phosphorus compounds are the true nucleo- 
 proteids. It is these compounds which, in the nuclei of cells, play so 
 important a part in the various phenomena of living matter. 
 
 That lecithin is a forerunner of these substances is shown by the 
 study of the disappearance of lecithin in the egg during incubation as 
 the embryo develops. 
 
 Whether the pseudo-nucleins are also forerunners of these true 
 nucleins has, so far as I am aware, never been considered. The fact 
 that they exist in large quantities in the yolk of the egg would indicate 
 that in them the phosphorus is also stored for use in the construction 
 of nucleins, while the possible combination of their phosphorus in 
 thymic acid a derivative of nucleic acid seems a further indication of 
 their relations to the true nucleins. 
 
 It would be difficult to find a more suitable object for the study of 
 some of the transformations of phosphorus than the salmon during its 
 prolonged fast, when its genitalia are being built up from its other 
 tissues. 
 
 Miescher Ruesch does not deal fully with the question. He states (p. 
 1 83) that the ovarian fluid, which readily exudes from the ripe ovary when 
 broken down, contains no less than 20 per cent, of lecithin, besides a 
 nuclein the amount and characters of which he does not discuss. He 
 points out that this has "general interest because both these substances, 
 especially the last named, are contained only in very small amounts in 
 muscle. The formation of the ovarian fluid can thus only take place by 
 the muscle substance being taken up from the flesh and laid on in the
 
 1 44 investigations on the Life-History 
 
 ovaries, but out of the albumen and fat and phosphorus-containing salts 
 of the muscle the characteristic combination of the egg must he formed 
 by the profoundest chemical changes.*' 
 
 He further states that " there is no doubt that the trunk muscles 
 contain more than* enough phosphoric acid to yield the phosphorus of 
 the ovary, with 1-1 per cent. P 2 O 5 in the fresh ovaiy, as against 2-3 
 per cent, to 2*6 per cent, in the dry sub-tance of the trunk muscles.'" 
 Ke gives no further figure in support of his statement. 
 
 It must be remembered that in the bones of the fish there is an 
 abundant supply of phosphorus, and that this, as well as the supply in 
 the muscles, may be available for the ovaries. 
 
 Before discussing the exchanges which take place between the phos- 
 phorus of the muscle and the genitalia, it will be well, in the first 
 instance, to consider in a general manner the nature of the phosphorus 
 compounds in each. 
 
 1 . NATURE OF PHOSPHORUS COMPOUNDS. 
 Methods. 
 
 The muscle after preservation in alcohol was pounded and repeatedly 
 extracted with hot alcohol and subsequently with ether. The extract 
 was evaporated and the phosphorus determined by igniting with caustic- 
 potash arid nitre (both phosphorus free) dissolving in water, acidifying, 
 filtering through paper extracted with acid, and precipitating the phos- 
 phates with ammonia-magnesia mixture, igniting, and weighing the 
 ash. From the magnesium phosphate the lecithin was calculated by 
 multiplying by 7'00. This factor was selected because it is midway 
 between the factors for stearin lecithin and olein lecithin. The phos- 
 phorus was determined by multiplying the magnesium phosphate bv 
 0-279. 
 
 The phosphorus not as lecithin was determined as follows : From 
 1 grm. to 2-5 grms. of the residue after extraction with ether were taken 
 for analysis. This was burned with caustic potash and nitre and dissolved 
 in water. Strong nitric acid was added, and the solution was heated on 
 a steam bath for several hours. Next (lay nitrate of ammonia and 
 molybdate of ammonia in excess were added, and the solution was kept 
 warm and allowed to stand for 12 or 24 hours. Jt was then filtered, 
 and the filtrate again treated with molybdate of ammonia, and if any 
 precipitate fell this was also thrown on the filter paper. The yellow 
 precipitate was washed through the paper with ammonia solution, and 
 the phosphates precipitated with ammonia - magnesia mixture and 
 ignited. From the magnesium phosphates the phosphorus was cal- 
 culated. 
 
 To ascertain the phosphorus as uucleins and as phosphates, the 
 residue after extraction of lecithin was then extracted with -2 per cent. 
 HC1., and the phosphorus determined in the extract. This extract 
 contained hardly any organic matter. , 
 
 The phosphorus of the residue was finally determined. 
 
 in this way the amount of phosphorus as lecithin, as inorganic 
 phosphates, ard as nucleins or pseudo- nucleins was ascertained. 
 
 A. PHOSPHORUS COMPOUNDS OF THE MUSCLES. 
 
 The amount of phosphorus in various form* in the muscles of different 
 animals has already been investigated by Katz. (Pflug. Arch., Bd. 63, 
 p. 1-18.) 
 
 in the eel and pike the two fish examined by him he obtained the 
 following results :
 
 of the Salmon in Fresh Water. 
 Phosphorus in 100 Parts Dried Muscle. 
 
 145 
 
 
 Total. 
 
 In Watery 
 
 Extract. 
 Phosphates. 
 
 In Alcohol 
 Extract 
 (Lecithin). 
 
 In Residue 
 (Nucleins). 
 
 Eel, 
 
 0-48 
 
 0-40 
 
 0-055 
 
 0-03 
 
 Pike, - 
 
 1-03 
 
 0-83 
 
 0-075 
 
 0-12 
 
 These analyses indicate tbat by far the greatest amount of phosphorus 
 is held in the muscles as phosphates. The amount in lecithin and 
 nucleins is comparatively small and unimportant. 
 
 The distribution of phosphorus was investigated in two salmon, one 
 from the estuary early in the year, and one, also from the estuary, later 
 in the year Nos. 14 and 76. 
 
 TABLE I. 
 
 distribution of Phosphorus in Muscles. 
 
 
 Ether 
 
 Extract. 
 
 Water 
 Extract. 
 
 Residue. 
 
 Total. 
 
 , r Thick, . 
 
 0-042 
 
 0-131 
 
 0-056 
 
 0-228 
 
 L 1 Thin, . 
 
 0-046 
 
 0-094 
 
 0-041 0-181 
 
 7fl { Thick, . 
 6 \ Thin, . 
 
 0-060 
 0-060 
 
 0-095 
 0-119 
 
 0-055 
 0-063 
 
 0-210 
 0-242 
 
 This Table shows that in the salmon, as in other fish, the greater- 
 part of the phosphorus of the muscle is in the form of inorganic 
 phosphates. The amount contained in lecithin appears larger in the 
 salmon than in the pike and eel, and the proportion as nucleins is also 
 larger. 
 
 A. very different distribution of this element is found in the 
 ovaries and testes. 
 
 B. PHOSPHORUS COMPOUNDS OF THE OVARIES. 
 
 1. General Distribution of Phosphorus. The distribution of phos- 
 phorus in the ovary was determined in the same way as in the muscle 
 in Nos. 14 and 76. 
 
 TABLE 11. 
 
 
 Ether 
 Extract. 
 
 Water 
 Extract, 
 
 Residue. 
 
 Total. 
 
 14 ... 
 
 : _ 
 0-114 
 
 0-057 
 
 0-114 
 
 0-285 
 
 76 
 
 0-150 
 
 0-075 
 
 0-189 
 
 0-414
 
 146 Investigations on the Life-History 
 
 In the ovaries the amount of phosphorus as inorganic phosphates is 
 very small. The amount as lecithin nearly equals the amount as 
 nucleins, or pseudo-nucleins, and in these two together the proportion 
 is about four times that in the inorganic phosphates. 
 
 2. Nature of Organic Phosphorus Compounds. The ripe ovary of a 
 November salmon was passed through the mincer to break up the ova, 
 and strained through muslin. The viscous brown-yellow fluid was then 
 diluted to three times its volume with solution of chloride of sodium, 
 and repeatedly extracted with ether. 
 
 A. ETHER EXTRACT. 
 
 On evaporation, this separated into (I.) a rich orange-red solution ; 
 (II.) a copious white gelatinous precipitate. 
 
 I. The orange-red solution, on standing, threw down fine needle-like 
 crystals readily redissolved on heating. The ether was distilled off and 
 the residue dried at 100 C. 
 
 a. Of this 3-042 grm. were saponified by Kossel and Obermiiller's 
 method and the fatty acids extracted. These weighed 2-929 grm., i.e., 
 92 - 8 per cent, of the ether extract. 
 
 b. In 2-066 grm. the presence or absence of phosphorus was 
 determined in the usual way. There was no precipitate with the 
 ammonia-magnesia mixture, so lecithin is absent. 
 
 c. 4-903 grm. were saponified and the cholesterin determined in the 
 ether filtrate. 
 
 Cholesterin = 0-012 grm. 
 
 = 0'24 per cent, of the ether extract. 
 
 The clear ether extract consists almost entirely of ordinary fats with a 
 little cholesterin and some lipochromes. 
 
 II. The White Precipitate from the Ether Extract. This separated out 
 as the ether evaporated, and was only redissolved with difficulty in a 
 large excess of ether. A small quantity was dried at 110C. It 
 weighed 1-225 grm. In this phosphorus was determined in the usual 
 way. 
 
 Magnesium Phosphate = 0'103 grm. 
 
 = 0-0287 grm. Phosphorus. 
 = 2-3 per cent, of Phosphorus. 
 
 Lecithin contains about 4 per cent. The white precipitate seems to be 
 largely composed of lecithin. 
 
 Thus, by simple extraction with ether, a large quantity of fats, 
 lecithin, some cholesterin, and pigment are removed from the ovarian 
 fluid. 
 
 B. PROTEID OF OVARY. 
 
 The fluid left, after extraction with ether, had a dirty brown colour, 
 and was somewhat viscous. 
 
 On pouring it into water a stringy white precipitate with the proteid 
 reactions at once fell. This was washed with water and redissolved 
 in salt solution. 
 
 1. Lecithin is combined with the Proteid. 
 
 A quantity of the proteid precipitated with alcohol was repeatedly 
 extracted with boiling absolute alcohol, and the extract filtered hot and 
 evaporated to dryness. A brownish sticky residue resulted. This was 
 dried at 100 C., and weighed 0-248 grm. In this the phosphorus 
 was determined in the usual way.
 
 of the Salmon in Fresh Water. 147 
 
 Magnesium Phosphate = -037 grin. 
 
 = -259 grin. Lecithin. 
 
 After extraction of the fats with ether, lecithin is left in closer 
 combination with the proteids. 
 
 2. Presence of Phosphorus in Proteid. 
 
 After extraction with hot alcohol and ether, and drying at 100" 
 C., 1-134 grm. of the proteid were used for determination of 
 phosphorus. 
 
 Magnesium Phosphate - -031 grm. 
 
 = '0086 grm. Phosphorus. 
 = '74 per cent, of Phosphorus. 
 After removal of the lecithin the proteid contains a further amount cf 
 
 3. Reactions of Proteid of Ovary. The proteid was found to be 
 insoluble in water ; soluble in dilute KHO, Na 2 C0 3 , and in neutral 
 salts. On the addition of an acid ic is precipitated, and is soluble only 
 in a considerable excess of acetic acid, but in a small excess of mineral 
 acids, e.g., -2 per cent. HC1. In a weak solution of neutral salts it is 
 not precipitated on boiling; but in a saturated solution of NaCl, in 
 which it is soluble, a copious precipitate is thrown down on heating. It 
 is precipitated by a half-saturated solution of (NH 4 ) 2 SO 4 . The 
 filtrate gives a cloud on boiling and the proteid reactions so a trace of 
 an albumin is present. A stream of CO., gives no precipitate. After 
 being precipitated for some time the proteid loses its solubility in 
 neutral salts. 
 
 4- Does the Proteid contain a Nuclein or Psuedo- Nuclein ? 2'26 grm. 
 were digested for 20 hours in artificial gastric juice. The residue on 
 drying weighed 0'109 grm. 
 
 A large quantity of the proteid was dissolved in -2 per cent. HG1 and 
 liquor pepticus added. On digesting a copious precipitate was thrown 
 down. This precipitate was washed with hot alcohol and ether, and the 
 phosphorus determined in '626 grm. ; it contained 0'0237 grins. P., or 
 3-7 per cent. 
 
 A considerable quantity of the moist proteid was boiled in 5 per cent. 
 H 2 SO 4 for several hours. A brownish solution resulted, with a slight brown 
 precipitate. This was filtered off. The filtrate was treated with baryta 
 water to neutralisation; the baryta was separated by a stream of CO., ; 
 the fluid was then filtered and ammonia added. No precipitate formed. 
 Ag N0 3 was then added, and no precipitate resulted. Hence nuclein 
 bases are absent. The brownish solution, when rendered alkaline and 
 boiled with Fehling's solution caused no reduction. 
 
 5. The, Proteid contains Iron. (Note by E. D. W. Greiy, M.B., C.M.) 
 In the earlier analyses of the ovarian proteid the iron was not 
 determined. 
 
 In an elaborate investigation Walter (Zeitschrift f iir physiol. Chemie, 
 Bd. XV., 1891, p. 477) showed that in the ovary of the carp both the 
 proteid and the nuclein derived from it contained iron. 
 
 I have also determined the quantity of iron present in the pure 
 ovarian proteid, and also in the nuclein obtained from it by artificial 
 digestion. 
 
 The proteid was obtained in the following manner : The fresh ovary 
 was passed through a mincer, and then strained through muslin. It was 
 then repeatedly extracted with ether, and about four times its volume 
 of salt solution (strong) added. This was then poured into a large 
 quantity of distilled water and repeatedly washed by decantation. It
 
 148 Investigations on the Life-History 
 
 was finally repeatedly extracted with hot alcohol and ether. The 
 powder thus obtained was dried and weighed. 
 
 The iron analysis was carried out in exactly the same manner as that 
 which is fully described in my investigation on "The Exchange of Iron 
 between the Muscle and Ovary of Salmon" (p. 156). In 2 grms. of 
 the ovarian proteid, -45 mgms. Fe, = 0*022 per cent. Fe. Avas found. 
 
 The Nuclein Avas obtained by digesting the pure proteid in 2 per cent. 
 HC1 and liquor pepticus at 40 C C. The residxie was extracted with 
 hot alcohol and ether, and washed with water till acid-free. A. very 
 fine light poAvder was left, which was dried at 110C. and weighed. 
 
 The iron analysis Avas conducted as before. Result : 2-5 gr. ovarian 
 nuclein contained 1*6 mgms. Fe, = 0.064 per cent. Fe. 
 
 The percentages are lower than those obtained by Walter. 
 
 Ovarian Proteid, - = O'llT per cent. (Walter). 
 
 Nuclein, - = 0-252 per cent. ., 
 
 This lower result is probably due to the greater accuracy of the 
 method here employed, though it may be due to difference in the com- 
 position of the ichthulin from the different fish. 
 
 6. Nature of the Ovarian Proteid. The proteid of the ovary is in 
 very close combination Avith a certain amount of lecithin, and when this 
 is removed a pseudo-nuclein is left. This proteid resembles closely the 
 ichthulin somewhat imperfectly described in 1854 by Valenciennes and 
 Fremy (Comptes rendus, T. 38, 1854, p. 471), and more fully investi- 
 gated by Walter (Ztsch. f. phys. Chem., Bd. XV., p. 477, 1891) in the 
 ovary of the carp, though having a somewhat higher proportion of 
 phosphorus and a smaller proportion of iron. Neumeister is probably 
 right in concluding (Physiol. Chem.) that it is not a chemical in- 
 dividual but a mixture of a proteid with lecithin on the one hand and a 
 pseudo-nuclein on the other.* 
 
 C. PHOSPHORUS COMPOUNDS OF THE TESTES. 
 
 The characteristic phosphorus compounds of the testes have already 
 been so ably and exhaustively investigated by Miescher-Rueseh (Arch. 
 f. exp. Path. u. Pharmac., Bd., 37, p. 100, 1896) that it is unnecessary 
 here to deal with them at length. The nuclein present contains true 
 nucleic acid linked to a base Avhich Miescher has called protamin. In 
 this paper, which has been most admirably put together by Professor 
 Schmeideberg after the death of the author, the characters of the protamin 
 and of the nucleic acid are carefully described. The quantitatiA 7 e 
 composition of the seminal fluid is discussed, the fluid part, the heads, 
 and the tails of the spermatozoa having been isolated and separately 
 studied. It is shown that while the tails contain an albuminous sub- 
 stance with fats and lecithin, and are very poor in other phosphorus- 
 containing substances (p. 142), the heads are rich in nucleic acid and 
 protamin, and very poor in fats and lecithin. The following (p. 139) 
 gives the composition of the heads by one method : 
 
 Nucleic acid, - - 60*50 per cent. 
 
 Protamin extracted by HC1, 19-78 
 
 Other substances 2-94 
 
 Still unknown residue, - - - 16'78 
 
 100,00 
 
 *Smce this was written a paper by Miescher bearing upon these questions has been 
 published " Histoehemischen und Physiologischen Arbeiten von Freidrich Miescher 
 BIT.
 
 of the /Salmon in Fresh Water. 
 
 149 
 
 After further investigation (p. 148), he concludes that, after extrac- 
 ion with alcohol and ether, the heads of the spermatozoa contain 
 60-50 per cent, of Nucleic acid. 
 35*56 ,, Protamin. 
 
 or 96-06 Neutral nucleate of protamin. 
 
 Some observations on the composition of the unripe testes are also 
 given. Miescher devised an ingenious method of dissolving away the 
 cell protoplasm, and he was thus able to study the chemistry of the 
 nuclei from which the heads of the spermatozoa are developed. He 
 shows thnt these nuclei contain nucleic acid and a proteid, " nuclear 
 albuminose," but almost certainly no protamin It is considered 
 possible that the albuminose is the precursor of the protamin. From 
 his observations on the metabolism of the salmon, he concludes that the 
 necessary phosphorus is carried to the testes as lecithin and there stored 
 in the protoplasm, which becomes the tail of the spermatozoon. He 
 further points out that since both nucleic acid and protamin are richer 
 in nitrogen than proteids, a very great loss of these from the muscles 
 must be necessary to yield the nitrogen, while a considerable nitrogen- 
 free part must be liberated which will be available as a source of energy. 
 The essential nature of the phosphorus compounds in the testes are thus 
 very different from the compounds of the ovaries. 
 
 To determine the distribution of phosphorus in these structures the 
 testes of 53 and 68 were analysed in the same manner as the ovaries. 
 
 TABLE III. 
 
 No. 
 
 Ether 
 Extract. 
 
 Water 
 Extract. 
 
 Kesidue. 
 
 Total. 
 
 53 
 
 063 
 
 068 
 
 161 
 
 292 
 
 68 
 
 063 
 
 040 
 
 178 
 
 278 
 
 The percentage amount of jrftosphoi'tis in the testes is thus no larger than 
 that in the ovaries. The amount in the form of lecithin is markedly less, 
 that in inorganic plwsphates about the same, while the phosp/torus in the 
 nucleins is in someivhat larger amount. 
 
 2. EXCHANGE OF PHOSPHORUS BETWEEN MUSCLE AND OVARIES. 
 The first question which it appeared desirable to investigate is : 
 
 (a) Is the lecithin stored in the trunk muscles sufficient to yield the lecithin 
 trhich accumulates in the ovaries? 
 
 Table IV. gives the per cent, of lecithin in ovaries and muscles in 
 four typical fish from the estuary from May to August ; and in three 
 typical fish from the upper waters in October and November. 
 
 [TABLE.
 
 150 
 
 Investigation* on flip Life-History 
 
 TABLE IV. 
 
 Percentage of Lecithin in Ovaries and Miisde. 
 ESTUARY FISH. 
 
 No. 
 
 Ovaries. 
 
 Thick. 
 
 Thin. 
 
 16 
 27 
 40 
 45 
 
 Average, 
 
 *2-10 
 2-35 
 1-99 
 2 23 
 
 0-76 
 0-70 
 0-56 
 0-70 
 
 0-93 
 0.68 
 0-48 
 0-53 
 
 2-17 
 
 0-68 
 
 0-65 
 
 UPPER-WATER FISH. 
 
 
 ; 
 
 
 62 
 
 2-36 
 
 0-59 
 
 0-74 
 
 64 
 
 4-09 
 
 0-49 
 
 094 
 
 67 
 
 3-18 
 
 0-42 
 
 0-56 
 
 Average, 
 
 3-21 
 
 0-46 
 
 0-74 
 
 Table V. gives the lecithin per Standard Fish. 
 
 TABLE V. 
 
 Lecithin per Standard Fish in Ovaries and Muscle. 
 ESTUARY FISH. 
 
 No. 
 
 Ovaries. 
 
 Muscle. 
 
 16 
 
 1-99 
 
 48-0 
 
 27 
 
 3-45 
 
 43-6 
 
 40 
 
 2-17 
 
 37-8 
 
 45 
 
 3-62 
 
 41-2 
 
 Average, . 
 
 2-81 
 
 4i"6 
 
 UPPER WATER FISH. 
 
 60 
 
 47-8 
 
 25-6 
 
 64 
 
 86-8 
 
 27-1 
 
 67 
 
 64-2 
 
 17-5 
 
 Average, . 
 
 66-1 
 
 23-4 
 
 Gain of ovaries, 63'3 gnns. Loss of muscle, 19'2 grms. 
 
 From this Table it is seen that the gain of lecithin in the ovary is 
 enormously in excess of the loss of lecithin from the muscle. The 
 muscle per unit of length lost only 19'2 grms., while the ovary gained 
 no less than 63 - 3 grms. 
 
 The source of the fatty acids of the ovarian lecithin presents no diffi- 
 
 * It has already been shown (p. 146) that the extraction of lecithin by ether from the ovaries is 
 probably not complete. In the "ovary there is thus even a larger quantity than is indicated by 
 these figures.
 
 of the Salmon in Fresh Water. 
 
 151 
 
 culty. It has already been shown that the muscle contains an ample 
 supply of fats to meet all such requirements. 
 
 It is the source of the phosphorus which requires investigation. The 
 insufficiency of the lecithin phosphorus of the muscle is shown in the 
 Table VI. 
 
 TABLE VI. 
 
 Phosphorus in Lecithin per Standard Fish. 
 ESTUARY FISH. 
 
 No. 
 
 Ovaries. 
 
 Muscle. 
 
 13 
 
 0-079 
 
 1-92 
 
 27 
 
 0-138 
 
 1-74 
 
 40 
 
 0-087 
 
 1-51 
 
 45 
 
 0-145 
 
 1-65 
 
 Average, . 
 
 0-109 
 
 1-70 
 
 UPPER- WATER FISH. 
 
 60 
 64 
 67 
 
 Average, 
 
 
 1-91 
 
 1-02 
 
 
 3-47 
 
 1-08 
 
 
 2-57 
 
 0-70 
 
 
 2-97 
 
 0-93 
 
 Gain of ovaries, 2-861. Loss of muscle, 0-877. 
 
 About 2 grms. of phosphorus in the lecithin of the ovary in the fish 
 of standard length is thus not derived from the phosphorus of the 
 lecithin of the muscle. 
 
 (b) Is the phosphorus in other combinations in the muscles sufficient to yield 
 the phosphorus of the lecithin and other phosphorus-containing bodies 
 in the ovaries ? 
 
 To determine this point, three typical fish from the estuaries from May 
 to August, and three typical fish from the upper waters in October and 
 November, were selected. 
 
 TABLE VII. 
 
 Percentage of Phosphorus not in Lecithin in Musde and Ovaries 
 ESTUARY FISH. 
 
 No. 
 
 Ovaries. 
 
 Thick. 
 
 Thin. 
 
 27 
 
 0-275 
 
 0-270 
 
 0-208 
 
 40 
 
 0-238 
 
 0-292 
 
 0-249 
 
 45 
 
 0-233 
 
 0-280 
 
 0-243 
 
 UPPER- WATER FISH. 
 
 64 
 67 
 70 
 
 0-333 
 0-435 
 0-363 
 
 0-250 
 0-209 
 0-199 
 
 0-208 
 0-218 
 0176
 
 152 
 
 Investigations on the Life-History 
 
 TABLE VIII. 
 
 Phosphorus not in Lecithin per Standard Fish in Jfuscle and Ovaries. 
 ESTUARY FISH. 
 
 No. 
 
 Ovaries. 
 
 Muscle. 
 
 27 
 40 
 45 
 
 Average, . 
 
 0-403 
 0-259 
 0-363 
 
 16-0 
 20-6 
 17-0 
 
 0-342 
 
 17-8 
 
 UPPER-WATER FISH. 
 
 64 
 
 7-03 
 
 10-9 
 
 67 
 
 8-79 
 
 8-1 
 
 70 
 
 7-34 
 
 6-9 
 
 Average, . 
 
 7-72 
 
 8-6 
 
 Ovaries gained 7'478 grms. Muscle lost 9*200 grms. 
 Taking together the phosphorus as lecithin and the phosphorus not as 
 lecithin 
 
 Muscle loses 9'97 grms. Ovaries gain 10*339 grms. 
 The phosphorus lost from the muscle is just about sufficient to yield the 
 phosphoric laid on by the ovaries, provided no phosphorus is excreted or 
 used in other ivays. 
 
 (c) Pliosphorus of Liver. 
 
 A possible source of the phosphorus is the liver. I have shown 
 that in many animals a considerable storage of lecithin may occur in 
 this organ. (J. of Phys., Yol. XIX., 1896, p. 167.) 
 
 Although the amount of fat in the liver of the salmon is comparatively 
 small, it seemed desirable to ascertain if, during the period of fasting, loss 
 of phosphorus from the liver goes on to any marked extent. 
 
 For this purpose six typical fish were selected, and the phosphorus of 
 the liver as lecithin and as other compounds was determined in the 
 usual manner. 
 
 Table IX. gives the results of these analyses. 
 
 TABLE IX. 
 
 Phosphorus of Liver. 
 ESTUARY FISH. 
 
 No. 
 
 Per Cent, of 
 Phos. in 
 Lecithin. 
 
 Per Cent, of 
 Phos. not in 
 Lecithin. 
 
 Total 
 per Cent, of 
 Phos. 
 
 Total Phos. 
 per Fish of 
 Standard 
 Length. 
 
 27 
 40 
 45 
 
 0-051 
 0-072 
 0-065 
 
 0-053 
 0-016 
 0-026 
 
 0-104 
 0-088 
 0-091 
 
 0-173 
 0-167 
 0-195
 
 of the Salmon, in Fresh Water. 
 
 TABLE IX. Continued. 
 UPPER- WATEII FISH. 
 
 153 
 
 
 Per Cent, of 
 
 Per Cent, of 
 
 Total 
 
 Total Phos. 
 
 No. 
 
 Phos. in 
 Lecithin. 
 
 Phos not in 
 Lecithin. 
 
 per Cent, of 
 Phos. 
 
 per Fish of 
 Standard 
 Length. 
 
 64 
 
 0-039 
 
 0-065 
 
 0-104 0-145 
 
 67 
 
 0-085 
 
 0-106 
 
 0-191 0-357 
 
 70 
 
 Analysis lost. 
 
 0-084 
 
 
 
 These observations indicate that there is no great storage of phos- 
 phorus in the liver, and no marked diminution in the amount as the season 
 advances. The liver cannot be regarded as the source of the phosphorus 
 for the ovaries, and it is rather to the bones that we must look for any 
 supply of this element over and above that yielded by the muscles 
 which may be necessary for the growth of the ovaries. 
 
 Considering the conditions of the observations the balance between 
 the phosphorus lost from the muscle and that gained by the ovaries is 
 fairly close, and would seem to indicate that the phosphorus stored in 
 the muscle is sufficient to yield the phosphorus gained by the ovaries. 
 
 It is not to be expected that the loss of phosphorus from the 
 muscle should exceed that required by the ovaries, as is the case with 
 the fats and proteids, for here no question of supply of energy is involved. 
 
 In its diet of marine fishes the salmon has an abundant supply of 
 phosphorus, e.g., in the phosphates of the bones, and it is of interest to 
 notice that in the intestinal mucus numerous opaque yellow nodules 
 are to be seen, which are composed of crystals of carbonate of lime 
 stained with bile pigments. Whether these are lime salts from which 
 the phosphorus has been removed we have no information. 
 
 EXCHANGE OF PHOSPHORUS BETWEEN MUSCLE AND TESTES. 
 
 Of the phosphorus exchange in the male, Miescher-Ruesch writes as 
 follows (loc. cit. p. 2 1 6): "The ripening of the testes in the male does not 
 require so large an amount of albumin and fat as in the ovary of the 
 female ; but instead of this, according to my investigations, just as 
 much more phosphates for the construction of the various constituents 
 of the spermatozoa rich in phosphorus. If we take the weight of the 
 ripe testis at 5 per cent, of the weight of the body, with 25 per cent, 
 dry solids with 11-3 per cent, phosphoric acid, we get 0-141 per cent, of 
 the body weight in phosphoric acid which the growing testis must take 
 from the blood, more than a half the amount contained in the ripe ovary 
 of a female ol the same size." 
 
 He does not in this paper further consider the source of this 
 phosphorus, though, as pointed out on p. 148, he deals with this question 
 in his later work. 
 
 To study the exchanges of phosphorus between muscle and testes, the 
 phosphorus as lecithin, i.e. the phosphorus in the ether extract, and the 
 phosphorus not as lecithin was determined in six typical male fish, 
 three from the estuaries and three from the upper waters throughout 
 the season.
 
 154 
 
 Investigations on the Life-History 
 
 TABLE X. 
 
 Per Cent. Phosphorus in Lecithin. 
 ESTUARY FISH. 
 
 No. 
 
 Thick. 
 
 Thin. 
 
 Testes. 
 
 13 
 
 0-028 
 
 0-026 
 
 0-022 
 
 56 
 71 
 
 Analysis lost. 
 0-032 
 
 0-042 
 
 0-053 
 
 UPPER-WATER FISH. 
 
 34 
 
 0-035 
 
 0-036 
 
 0.045 
 
 39 
 
 Analysis lost. 
 
 
 
 68 
 
 0-022 
 
 0-037 
 
 0-037 
 
 TABLE XI. 
 
 Per Cent. Phosphorus not as Lecithin. 
 ESTUARY FISH. 
 
 No. 
 
 Thick. 
 
 Thin. 
 
 Testes. 
 
 13 
 56 
 71 
 
 0-243 
 0-234 
 0-250 
 
 0-261 
 0-197 
 0-270 
 
 0-265 
 0-243 
 0-296 
 
 UPPER-WATER FISH. 
 
 34 
 39 
 
 68 
 
 0-252 
 0-188 
 0-193 
 
 0-228 
 0-204 
 0-200 
 
 0-318 
 0-243 
 0-240 
 
 It is thus seen that there is no great increase in the per cent, of 
 phosphorus as the testes increase. 
 
 To show the extent of the exchange of phosphorus the amount of that 
 substance per fish of standard length as lecithin and not as lecithin may 
 be compared in 13, a fish leaving the sea in May, and in 68, a fish 
 in the upper water in October. 
 
 Table XII. gives the Phosphorus as Lecithin (A); the Phosphorus not 
 us Lecithin (B) ; and the Total Phosphorus (C) per fish of standard 
 length. 
 
 TABLE XII. 
 
 No. 
 
 MUSCLE. 
 
 TESTES. 
 
 C. 
 
 ' 
 
 
 C. 
 
 A. 
 
 B. 
 
 13 
 68 
 
 1-43 
 1-32 
 
 13-90 1 
 10-27 
 
 j 
 
 15-33 
 11-59 
 
 0'002 
 0-103 
 
 0-029 
 0-645 
 
 0-031 
 0-748
 
 of the, Salmon in Fresh Water. 155 
 
 Loss of Phosphorus by Muscle 3-740 
 Gain Testes 0-717 
 
 Surplus 3-023 gnus. 
 
 It would thus appear that the store of phosphorus in the muscle is 
 far more than sufficient to yield the phosphorus required in the con- 
 structive changes in the testes. 
 
 It is interesting in this connection to note that in the male during the 
 summer months there is a great growth of bone in the snout, and it is 
 highly probable that some of the phosphates stored in the muscles is 
 utilised in this process. 
 
 GENERAL CONCLUSIONS. 
 
 These observations on the distribution and exchanges of phosphorus 
 in the salmon throughout its sojourn in fresh water show that a supply 
 of phosphorus, partly as inorganic phosphates, partly as lecithin, is 
 stored in the muscles as these grow and become loaded with fat during 
 the stay of the fish in the sea. 
 
 While the fish is in the river this stored phosphorus is transmitted 
 from the muscle to the growing ovaries and testes, and in being trans- 
 mitted undergoes changes in its chemical combinations. In the ovary 
 the simple phosphates of the muscle are, (a) combined with fatty 
 acids and cholin to form the abundant supply of lecithin ; (6) combined 
 with proteids to form the pseudo or para nuclein ichthulin which is 
 so abundant a constituent of the ovary, (c) In the testes, on the 
 other hand, the phosphorus of the muscle phosphates is elaborated with 
 the more complex nucleic acid and combined with the characteristic 
 base protamin. 
 
 The source of these two nitrogenous bases the cholin of the 
 lecithin and the protamin of the nuclein of the testes we do not at 
 present know. They must ultimately be derived from proteids since 
 these are the only nitrogen-containing constituents of the body, and 
 Miescher has suggested that the "albuminose" of the early testis is 
 the forerunner of the protamin of the ripe organ. 
 
 There is no evidence that the transference of phosphorus from the 
 muscles to the genital organs is not direct. There is no evidence that 
 the liver plays any intermediate part. In fact, all the evidence tells 
 against such an idea. It is apparently in and by the active protoplasm 
 of the growing ovaries and testes that these profound chemical changes 
 are carried out. 
 
 These observations indicate that from the simple phosphates of the 
 muscle, by synthesis, lecithin, the ichthnlin of the ovaries, and the nucleic 
 acid of the testes are all built up. That lecithin is a stage in the pro- 
 duction of the ichthulin of the ovary and nuclein of the testis seems to 
 be indicated first by its accumulation in the muscles, and second by its 
 appearance in both ovaries and testes. That it is a forerunner of the 
 nucleins and phosphorus compounds of the embryo is undoubted. 
 As to the source of the phosphorus stored in the muscle, there can be 
 little doubt that it is in great measure derived from the phosphates in 
 the bones of herring and other fish upon which the salmon feeds. Th<> 
 evidence is against the idea that the lecithin of the muscles is also direct !\ 
 taken from the lecithin in the food, for Hasebrock (Ztsch. f. phys. Chan., 
 Bd. XII., 150) has shown that in the intestine lecithin is split up into 
 glycero-phosphoric acid, cholin, and fatty acids. There must thus be 
 synthesis of this material in the body.
 
 156 Investigations on the Life- History 
 
 14. THE EXCHANGE OF IRON BETWEEN MUSCLE 
 AND OVARIES OF SALMON. 
 
 BY E. D. W. GREIG, M.B. EDIN. 
 
 It has already been shown in another part of this Report (p. 147) 
 that iron is present in the paranuclein of the ovaries of salmon. 
 
 This investigation was undertaken to determine (1) whether the 
 quantity of iron present in the ovaries increases during their growth, and 
 if so (2) from what source it is derived. In considering the possible 
 sources of supply, it was at once obvious that the food ingested could l>e 
 excluded, as evidence has been adduced (p. 13 etseq.) to show that salmon do 
 not take nourishment during their sojourn in the river. Did the ovary, 
 then, as in the case of its fats and proteids, obtain the whole of the 
 iron required from the muscle ? or did part only come from muscle, and 
 the remainder from some other source, e.g., liver or blood ? 
 
 To elucidate this the amount of iron in the muscles, ovaries, and in 
 the livers of two typical fish leaving the sea in May, and in two typical 
 fish from the upper reaches of the river in October, was determined. 
 The very tedious nature of the analyses prevented a krger series of 
 observations being accomplished. The close correspondence in the 
 results obtained, however, indicates that the conclusions may be safely 
 accepted. 
 
 Method. The method employed in the analyses was that devised by 
 Stockman (Journal of Phys., xviii., p. 485, 1895). The steps may. for 
 convenience, be briefly recapitulated here. 
 
 Portions of the dried residue of the tissue, after extraction with 
 ether, were dried in the hot-air chamber and weighed. In the case of 
 the livers, a portion of the organ was pounded down and extracted with 
 alcohol for several days, and then dried and weighed. They were then 
 completely ashed in porcelain. The ash was extracted overnight with 
 strong HC1, and next morning dilute H 2 SO 4 was added, and the 
 whole heated. It was then filtered through ash-free filter paper, and 
 the filtrate placed on the steam bath to drive off the HC1. The iron 
 was then left dissolved in the H^SO^ A few drops of potassium per- 
 manganate were added, and it was set aside for several days. If the 
 colour remained (showing that all organic matter was destroyed), it wa* 
 then reduced with zinc, and titrated with a standardised solution of 
 potassium permanganate. 
 
 All the reagents, &c., were tested, and found iron-free. 
 
 The following Tables give the results of these analyses in grins. :
 
 of the Salmon in Fresh Water. 
 
 TABLE I. 
 Per Cent, of Iron in Ovaries, Muscle, and Liver. 
 
 157 
 
 Estuary Fish. 
 
 Ovaries. 
 
 Muscle. 
 
 Liver. 
 
 Thick. 
 
 Thin. 
 
 20 
 25 
 
 Average, 
 
 0-003 
 0-004 
 
 0-0015 
 0-0014 
 
 0-0018 
 0-0018 
 
 0160 
 
 0-0035 
 
 0-00145 
 
 0-0018 
 
 
 
 Upper- Water Fish. 
 
 Ovaries. 
 
 Muscle. 
 
 Liver. 
 
 Thick. 
 
 Thin. 
 
 63 
 
 69 
 
 Average, 
 
 0-003 
 0-002 
 
 0-002 
 0-002 
 
 0-001 
 0-001 
 
 0180 
 
 0-0025 
 
 0-002 
 
 0-001 
 
 
 
 TABLE II. 
 Iron in Ovaries, Muscle, and Liver, in Fish of Standard Length. 
 
 
 
 Muscle. 
 
 
 Estuary Fish. 
 
 Ovaries. 
 
 
 
 
 Liver. 
 
 
 
 Thick. 
 
 Thin. 
 
 Total. 
 
 
 20 
 
 0-005 
 
 0-076 
 
 0-031 
 
 0-107 
 
 0248 
 
 25 
 
 0-0059 
 
 0-0704 
 
 0-0308 
 
 0-109 
 
 
 
 Total, . 
 
 0-0109 
 
 _ 
 
 _ 
 
 0-216 
 
 
 
 Average, 
 
 0-0054 
 
 
 
 
 
 0-108 
 
 _ 
 
 
 
 Muscle. 
 
 
 Upper- Water Fish. 
 
 Ovaries. 
 
 
 
 
 Liver. 
 
 
 
 Thick. 
 
 Thin. 
 
 Total. 
 
 
 65 
 
 0-0631 
 
 0-067 
 
 0-014 
 
 0-081 
 
 02489 
 
 69 
 
 0-0506 
 
 0-0603 
 
 0-0123 
 
 0-0726 
 
 
 
 Total, . 
 
 0-1137 
 
 
 
 
 
 0-1536 
 
 
 
 Average, 
 
 0-0568 
 
 
 
 
 
 0-0763 

 
 158 Investigations on the Life-History 
 
 From the above Table it will be observed that the ovaries gain in iron 
 at the expense of the muscle, thus : 
 
 1. Loss of Iron, 
 
 Muscle of Fish in Lower Water = 0-1080 
 Muscle of Fish in Upper Water = 0-0763 
 
 Loss of Iron by Muscle = 0-0317 
 
 2. Gain of Iron. 
 
 Ovaries of Fish in Upper Water = 0-0568 
 Ovaries of Fish in Lower Water = 0-0054 
 
 Gain of Iron by Ovaries = 0-0514 
 
 Total Loss = 0-0317 
 Total Gain = 0-0514 
 
 Difference = 0-0197 
 
 i.e., 39 per cent, of iron gained by the ovaries is not derived from the 
 iron stored in the muscles. 
 
 CONCLUSIONS. 
 
 It may be claimed that the results of the analyses have demon- 
 strated ( 1 ) that the quantity of iron in the ovaries becomes distinctly 
 increased during the development of that organ, (2) that a considerable 
 amount of its iron is derived from the muscles, which become corre- 
 spondingly poorer in iron, (3) that none of it is derived from the liver. 
 
 Although the muscles supply the ovaries with the greater part of their 
 iron, yet there is a small quantity unaccounted for. The tissue which, 
 in all probability, supplies this, is the blood. If such observation had 
 been possible, it would have been of interest to investigate the changes 
 in the hsemoglobin of the blood. Since the iron has been shown to be 
 largely derived from the muscles, the amount from this source must be 
 comparatively small. There is no indication that the store of iron in 
 the liver is called upon. The iron which is stored up in the muscles 
 is probably obtained from the food, and kept in the muscles until the 
 development of the ovaries commences.
 
 of the Salmon in Fresh Water. 159 
 
 15. THE PIGMENTS OP THE MUSCLE AND OVARY OF 
 OP THE SALMON AND THEIR EXCHANGES. 
 
 BY M. I. NEWBIGLN, B.Sc. 
 
 Among the many curious and interesting changes which the salmon 
 undergoes throughout the year, not the least interesting is the variation 
 in colour seen in the skin, the muscle, and the ovaries. 
 
 When the fish comes from the sea the skin is of a clear, bright 
 silvery hue, while the flesh has the familiar strong pink colour. The 
 small ovaries are of a yellow-brown colour. As the reproductive organs 
 develop during the passage up the river, certain definite colour changes 
 occur. The skin loses its bright silvery colour, and, more especially in 
 the male, acquires a ruddy-brown hue. At the same time the flesh 
 becomes paler and paler, and in the female the rapidly growing ovaries 
 acquire a fine orange-red colour. The testes in the male remain a 
 creamy white. 
 
 After spawning the skin tends in both sexes to lose its ruddy colour, 
 and to regain the bright silvery tint ; the flesh, however, remains pale 
 until the kelt has revisited the sea. In other words, the salmon comes 
 from the sea with a store of pigment in the muscles. During its 
 sojourn in the river this pigment disappears from the muscles, is appar- 
 ently in the female for the most part transferred to the ovaries, and so 
 to the ova, and in both sexes is to a smaller extent deposited in the 
 skin, there to undergo f urther changes. The accumulation of pigment 
 in the muscle is associated with the presence of a large amount of fat, 
 and fat and pigment disappear pari passu. 
 
 While in the Salmonidse this colour change is most marked in the 
 salmon, it is also observable in the sea trout. Even in certain varieties 
 of brown trout, e.g. the Loch Leven trout, the pigmentation of the flesh 
 is well marked when the fish are in prime condition, and becomes less 
 marked as the genitalia develop. In all cases there seems to be the 
 same close association between fat and pigment, and the simultaneous 
 disappearance of the two. 
 
 Even outside the limits of the family of the Salmonidse, pigmentation 
 of the flesh is known to occur. Thus the Dawson salmon of the 
 Australians ( Osteoi/lossum leichardti), a member of a small tropical 
 family, is described as having pink-coloured flesh,\vhich tastes like that 
 of the English salmon. The flesh of the Australian mud-fish (Ceratodus 
 forsteri), again, is described as being oily and of a dark red or pink 
 colour. Although there is no direct evidence, the descriptions would 
 lead one to believe that in these cases also the pigment is associated 
 with the presence of fat in the muscle. 
 
 As the pigments in these and other cases have been directly ascribed
 
 160 Investigations on the Life-History 
 
 to the food, it was thought that their investigation in the case of the 
 salmon would be of some interest. In this animal the pigments do not 
 seem to have been previously studied. 
 
 METHODS OF SEPARATION. 
 
 If the red flesh be pounded up in a mortar with sand, and then 
 extracted with ether, it yields to the ether practically all its pigment. 
 The ether becomes a deep golden-yellow colour, and leaves merely a 
 greyish mass behind. On the evaporation of this extract a mass of 
 pinkish pigment mixed with other substances is obtained. The pink 
 pigment when treated with concentrated sulphuric or nitric acid gives 
 a pure blue colour, which fades very rapidly, especially if water be 
 added. 
 
 This reaction shows that the muscle contains one of the class of pig- 
 ments called lipochromes, which are characterised by their solubility in 
 ether, chloroform, benzol, petroleum ether, alcohol, etc. ; by their colour, 
 which varies from yellow to red ; and by the fact that they give a blue 
 colour when treated with concentrated acid in the dry state. In order 
 to obtain the pigment pure, for further study, the method of sa.poni- 
 tication was resorted to. 
 
 Two methods of saponification are available : (1) by means of 
 metallic sodium in ethereal solution ; (2) by means of caustic soda in 
 alcoholic solution ; both methods were employed. 
 
 1. Small pieces of metallic sodium were added to a golden -yellow 
 extract of the flesh in ether ; on standing, the soap separated out at 
 the base of the flask and was of a reddish colour, while the ether 
 remained clear yellow. The ether was poured off and the soap washed 
 with fresh ether, which did not extract the pigment. The soap was 
 then dissolved in water, which became a pure pink colour. The addition 
 of a little acetic acid to this solution gave a pink precipitate, which was 
 filtered off. This pink precipitate dissolved readily in ether, to form, 
 when dilute, a yellow solution, and in alcohol to form a pink solution. 
 It also dissolved in petroleum ether, benzol, chloroform, etc., and gave 
 a beautiful blue colour with concentrated sulphuric or nitric acid. 
 
 The yellow ether obtained by this method of saponification, after 
 iiltering off the soap, left on evaporation a pure yellow pigment which 
 did not give a blue colour with concentrated sulphuric or nitric acids. 
 
 The ether of saponification is never anhydrous, and therefore when 
 evaporated it usually leaves some drops of caustic soda solution behind ; 
 the yellow pigment readily dissolves in this. 
 
 2. In this method an alcoholic extract of the muscle was boiled with 
 caustic soda. A slight precipitate of red pigment was obtained from the 
 solution, but the mass of the pigment remained in solution with the 
 soap. 
 
 To obtain the red lipochrome from this solution, two methods may be 
 employed. The soap and the pigment may be precipitated by the addi- 
 tion of common salt, or the caustic solution may be shaken with ether in 
 a separation funnel. 
 
 If excess of common salt be added to the caustic solution, a. bright red 
 soap comes down, leaving the solution a clear yellow colour. The soap 
 may be washed with alcohol and then treated with dilute acid, after 
 which the pigment is readily removed by alcohol, in which it forms a 
 pink solution. 
 
 A simpler method is to shake the caustic solution after removal of the 
 alcohol with ether, when the ether becomes deep yellow, leaving the 
 caustic solution also yellow. The evaporation of the ethereal solution 
 leaves a red pigment, which gives as before the lipochrome reactions.
 
 of the Salmon in Fresh Water. 161 
 
 The yellow pigment remains in the caustic solution, from which it 
 cannot be extracted by ether or petroleum ether. It is not precipitated 
 by the addition of acid, but the solution is then decolorized. 
 
 CHABACTERS OF PIGMENTS. 
 
 The above observations show that the red flesh of the salmon contains 
 two pigments, of which one is pink, and gives the blue lipochrome 
 reaction, while the other is yellow, and does not give this reaction. 
 
 An investigation of the mature ovaries conducted in precisely similar 
 
 fashion showed that in them also two pigments a red and a yellow 
 
 combine to produce the normal coloration of the organs. 
 
 The Red Pigment. The characters of this red pigment are as follows: 
 It is a lipochrome pigment, giving a blue colour in the dry state with 
 nitric or sulphuric acid, and is soluble in alcohol, ether, benzol, petroleum 
 ether, and acetic acid. Except in ether and petroleum ether, the solu- 
 tions are of a pink or reddish colour, while these two solvents form pure 
 yellow solutions. If the solutions are evaporated, the pigment recovers 
 its red colour as the last drop of the solvent disappears. 
 
 The pigment forms compounds with caustic soda and potash, which 
 are soluble in dilute alkaline solutions, at least in the presence of soaps. 
 From these solutions the pigment may be precipitated by the addition 
 of dilute acetic acid, or may be directly extracted by means of ether. 
 Similar compounds are formed with lime and baryta. 
 
 The pure dry pigment fades very rapidly either in light or in dark- 
 ness. Solutions also fade, but much more slowly. The loss of the power 
 of giving a blue colour with concentrated acid is one of the first signs 
 of change, and it may occur before the loss of colour in the solution is 
 obvious. Pigment dissolved in benzol seems especially liable to undergo 
 this change. 
 
 As to its other characters, solutions of the pigment when examined 
 with a microspectroscope exhibit an indefinite shading in the neighbour - 
 hoodof the F line, but this is hardly visible when the solutions are 
 examined with a spectroscope of larger dispersion. In this case there is 
 merely continuous absorption of the violet end. 
 
 As a whole, the pigment corresponds closely to the lipochrome pig- 
 ment described in various animals, and notably in Crustacea, as tetro- 
 nerythrin or zoonerythrin (by Moseley as crustaceorubrin). From the red 
 pigment of the lobster the pigment differs slightly in tint and in the 
 solubility of the sodium compound, but it is uncertain how much stress 
 should be laid upon these differences. 
 
 The Yellow Pigment. The yellow pigment does not give the lipochrome 
 reaction. It belongs to a group of pigments which are apparently exceed- 
 ingly widely distributed in the animal kingdom, but which have been little 
 investigated. They have been commonly confounded with the lipo- 
 chrome pigments. In the salmon the pigment occurs in the muscle, the 
 ovary, and in large amount in the liver. It is always in close associa- 
 tion with fat, and its solubility seems to depend upon that of the 
 associated fat. In the salmon the pigment is associated with the fat 
 olein, which is soluble in methylated spirit, and the pigment is also 
 soluble in this solvent. In the case of bright yellow fat obtained from 
 a cow, a pigment of otherwise identical characters was very little 
 soluble in cold methylated spirit, but dissolved readily in ether. 
 The fat with which the pigment was associated was here stearin and 
 not olein. 
 
 The yellow pigment does not apparently form compounds with the 
 alkalies or alkaline earths. It remains in the ether when an ethereal
 
 162 Investigations mi the Life-History 
 
 solution is saponified by metallic sodium, and in the caustic solution 
 when an alcoholic solution is saponified by caustic soda. 
 
 DISTRIBUTION OF THE PIGMENTS. 
 
 It is interesting to note that the relative amounts of the two 
 pigments vary considerably. As the flesh grows paler, it is the red 
 pigment which seems to disappear first. While the ovary is small it 
 contains chiefly the yellow pigment, while as it increases in size the 
 amount of red pigment also increases. It would thus seem that there 
 is a direct transference of the red pigment from the muscles to the ova, 
 along with the transference of fat. Both pigments occur dissolved in fat. 
 
 SIGNIFICANCE OF THE PIGMENTS. 
 
 In this connection the first point of inte rest is that two pigments of similar 
 or perhaps identical nature occur in the lobster and in all probability in 
 other Crustacea. In the smaller Crustacea, as yet, the red pigment only 
 has been described. In the Crustacea the pigments, especially the red 
 one, are exceedingly important in producing the external coloration. 
 In the lobster the digestive gland contains a considerable amount of fat 
 which has a yellow pigment associated with it. The blood contains a 
 red lipochrome, but no yellow pigment, while the hypodermis contains a 
 large amount of red lipochrome, and apparently a small amount of 
 yellow pigment. The red lipochrome forms a combination with some 
 base, and then gives rise to the blue colour of the shell. 
 (See Jour, of Physiol., 1897, p. 249). There is some reason to believe 
 that in the lobster the yellow pigment and the red are closely related to 
 one another. The yellow pigment contained in the digestive gland is in 
 part got rid of by means of the alimentary canal, where it acts like a 
 true bile-pigment in colouring the faeces, and is probably in part modi- 
 fied to form the red pigment of the hypodermis and shell. 
 
 Now, as to the relation of these facts to the pigmentation of the 
 muscle of the salmon. The most obvious explanation is that the pig- 
 ments of the salmon are derived directly from its food, and this is one 
 which has been made by Gunther, and accepted by other authors, e.g., 
 by Beddard in his " Animal Coloration." At first sight the suggestion 
 has much to recommend it. The pigments are very similar to those of 
 the Crustacea, and perhaps identical with them. They disappear during 
 the period of fasting, and are regained when the animal begins again to 
 take food. In certain brown trout they appear sporadically, as if 
 dependent upon particular diet, and finally the pigments are widely 
 distributed in the Crustacea, occurring in one form or another in fresh- 
 water, littoral and abyssal forms. 
 
 There are, however, some difficulties in the way of the acceptance of 
 this suggestion. In the first place, the salmon seems to feed chiefly on 
 haddock, herring, and similar fish, so that the transfer of pigment can 
 hardly be direct. The herring, however, feeds habitually on small 
 Crustacea, so that it might be said that the pigments of the salmon are 
 obtained indirectly from the herring which forms its food. In consider- 
 ing such a suggestion we have first to remember that the muscle contains 
 two pigments, a red and a yellow, which simultaneously exist in the 
 Crustacea. Of these pigments there is no reason to believe that the 
 red exists in the herring. In three specimens examined I was unable 
 to find any trace of it, either in the muscle or in the viscera. The stomachs 
 in these cases were almost empty, but it hardly seems probable that the 
 amount of pigment in the undigested food of the herring could be 
 sufficient to supply all the colouring-matter of the salmon's muscle. 
 
 As to the yellow pigment, the viscera of the herring yielded to cold
 
 of the Salmon in Fresh Water. 163 
 
 methylated spirit a small amount of a pigment which resembled the 
 pigment obtained from the liver of the salmon, the same pigment bein- 
 present in traces in a muscle extract. This suggests the possibility 
 that the salmon obtains the yellow pigment of its muscle from food in 
 association with fat, and that part of this pigment is modified to form 
 the red. In the lobster there is some reason to believe that the yellow* 
 pigment is capable of being transformed into the red, and the conditions 
 under which the two exist in the salmon suggest the possibility of a 
 similar transformation there. As to the possibility of transference of 
 yellow pigment from one organism to another, there is some evidence 
 apart from the case of the salmon. Thus Poulton (Proc. Roy. Soc., Lon- 
 don, liv., pp. 417-430; see also Nat. Sci., vol. viii., pp. 98-100) has shown 
 by experiment that certain caterpillars derive their pigments from their 
 food. Again, it is not uncommon to find the fat of sheep and cows dyed 
 .a deep yellow colour. According to some authorities, this occurs quite 
 sporadically without known cause, while according to others special 
 foods, notably maize, are the important agents. I have examined the 
 yellow pigment of maize and compared it with pigment from yellow 
 fat. The maize pigment gives the lipochrome reaction, faintly with 
 sulphuric acid, distinctly with nitric, while the fat pigment gives no 
 lipochrome reaction. In other respects, in tint, in solubility, and so on, the 
 pigments closely resemble each other-. This fact, taken in combination 
 with Mr Poulton's experiments, seems to me at least to prove the 
 possibility of the transference of these pigments from one organism to 
 another, and therefore to suggest such an origin for the yellow pig- 
 ment of the salmon. 
 
 This suggestion, however, gives rise at once to the difficulty that 
 unless these three organisms can be shown to possess some common 
 physiological peculiarity, then we are forced to the conclusion that 
 all yellow pigments in animals are derived from their food a conclusion 
 for which there seems little evidence. Further, if the presence of pig- 
 ment in the food is the only condition necessary to produce pigmented fat, 
 it is difficult to understand why such coloured fat should not be 
 universal in herbivorous animals, for all green parts of plants contain 
 also a certain amount of yellow pigment. 
 
 It seems to me, however, that it is possible to point to a peculiarity 
 possessed in common by the salmon, domesticated cattle, and cater- 
 pillars, namely, the habit in each case of ingesting food in excess of the nor- 
 mal requirements of the organism at the time of feeding. That this is so in 
 the case of sheep and cattle undergoing the artificial process of fattening is 
 obvious. Again, in both caterpillars and salmon the life-history is sharply 
 divided into nutritive and reproductive periods, the periods occurring, 
 respectively, once in the life of the caterpillar, and annually in the case 
 of the salmon. During the nutritive period in both cases there is a 
 large ingestion and deposition of fat, which later furnishes the energy 
 used up during the reproductive period. It seems to me not unreason- 
 able to suppose that while an organism which ingests a moderate amount 
 of coloured fat is able to utilise or eliminate the pigment, and so deposit 
 colourless fat in the tissues, one in which the ingestion of this coloured 
 fat is excessive may be unable to do this, and so store coloured fat. In 
 Poulton's caterpillars part of the pigment was eliminated with the faeces, 
 which suggests that elimination is the natural fate of the pigment. If 
 this explanation be correct, then it would follow that the reason for the 
 coloration of the fat in sheep fed on maize must be that the ordinary 
 diet contains as much pigment as it is possible for the organism to deal 
 with, and the further addition of the pigmented fat of maize causes 
 merely deposition of slightly altered pigment in the tissues.
 
 164 Investigations on the Life- History 
 
 If we apply this explanation to the salmon, we have of course to face 
 the possibility that both the red and yellow pigment are ingested in 
 this way with the food. On the whole, this seems to me improbable, 
 and I am inclined to believe that it is only the yellow pigment which is 
 so obtained, but that owing to the conditions to which it is exposed in 
 the muscle, it becomes in part converted into the red, which then gives 
 rise to the colour of muscle and ova. 
 
 It is interesting to observe that smolt which was kept at Howietoun 
 for three years developed ripe ova. These had the characteristic red 
 colour. (Day's British and Irish Salmonidse, p. 102). 
 
 I am thus of opinion that the presence of pigment-containing fat in 
 cattle, in caterpillars, and in the salmon, is due in each case to the habit 
 of ingesting coloured fatty food in an amount which is in excess of the 
 immediate requirements, the consequence being that fat coloured with 
 the pigment in a more or less modified condition is deposited in certain 
 of the tissues. While the pigment so deposited is of no importance in 
 cattle, in caterpillars it is important in producing the external coloration, 
 and in the salmon in colouring the ova. In the male salmon the pig- 
 ment is probably eliminated as the fat is used up. The question is of 
 some interest, because if the suggestion here made be correct, it shows 
 that a characteristic pigmentation may be acquired as it were inciden- 
 tally in the course of the life history of the individual, under circum- 
 stances which render the question as to the inheritance of acquired 
 characters absolutely unimportant.
 
 of the, Salmon in Fresh Watei'. 165 
 
 16. ON THE CHANGES IN THE VALUE OF SALMON 
 AS A FOOD STUFF. 
 
 BY JAMES C. DUNLOP, M.D., F.K.C.P.E. 
 
 The measurements and analyses of salmon at the different seasons of 
 the year, described in the previous sections, enable us to consider the 
 value of the fish as a food stuff. Every salmon killed, whether early or 
 late in the year, causes the loss of one breeding unit. If the stock is 
 inexhaustible it matters not how many breeding units are destroyed. 
 But if, as is the case, the stock is a diminishing one, economy demands 
 that there must be a selection of fish, only those which give the best 
 return being killed, and those which, on account of their poor value 
 as a food stuff, do not compensate for that loss to the breeding stock, 
 being preserved. The subject of killing salmon for sport is outside the 
 scope of this section. 
 
 Two methods of considering the value of salmon flesh as a food stuff 
 suggest themselves (1) The value per unit of weight of flesh, per 
 100 grms. may be taken ; or (2) the total value per fish killed may be 
 calculated. Both these will be considered. 
 
 The value of a food stuff is measured by the amount of energy which 
 the combustion of its constituents produces, and is expressed as the 
 number of calories heat units produced by that combustion. Calories 
 are adopted as a convenient measurement of energy ; but when the 
 energy value of a food stuff is expressed as so many calories, it is not 
 implied that that food stuff is only capable of producing heat. One 
 form of energy is capable of conversion into other forms, and so the 
 measurement of the production of heat may be taken as a measurement 
 of the energy available for all purposes. The calories referred to in this 
 article are " great calories," each representing the amount of heat 
 required to raise the temperature of 1000 cc. of water 1 Centi- 
 grade. For practical purposes the food value of the flesh of fish may bo 
 considered to depend on two constituents, proteids and fats, carbo- 
 hydrates occurring in such a small amount that they may be dis- 
 regarded. In the calculations which follow, the measurements and 
 analyses of the fish are taken from the figures in the previous sections of 
 this work, while the calorie value of proteid and fat is taken from 
 Neumeister's Physiologische Chem., I., p. 282. 
 
 Food Value per Hundred Grms. of Salmon Flesh at Different Seasons. 
 
 In the following tables will be found a statement of the amount of 
 proteid and fat and calorie equivalent of the flesh of the salmon at the 
 different seasons, both from estuaries and upper waters. The calcula- 
 tions are based on the averages of the actual amounts found in each 
 group of female fish received in 1896 (vide pp. 95 and 122).
 
 166 
 
 Table I. gives 
 in calories. 
 
 Investigations on the Life-History 
 the percentage of proteids and fats, and the food value 
 
 TABLE I. 
 
 ESTUARY FISH. 
 May and June. 
 
 Proteid, 
 Fat, . 
 
 Calories, 
 
 Thick Muscle. 
 
 Thin Muscle. 
 
 Total Muscle. 
 
 21-2 
 10-2 
 
 18- 
 17-9 
 
 20-6 
 12-1 
 
 181-7 
 
 244-1 
 
 197- 
 
 July and August. 
 
 Proteid, 
 Fat, . 
 
 Calories, 
 
 Thick Muscle. 
 
 Thin Muscle. 
 
 Total Muscle. 
 
 21-8 
 9-8 
 
 18-7 
 16-8 
 
 21-0 
 11-5 
 
 180-5 
 
 233-0 193- 
 
 October and November. 
 
 Proteid, 
 Fat, . 
 
 Calories, 
 
 Thick Muscle. 
 
 Thin Muscle. 
 
 Total Muscle. 
 
 20-0 
 5-4 
 
 20-0 
 10-2 
 
 20-0 
 6-6 
 
 132-2 
 
 176-8 
 
 143-4 
 
 UPPER-WATER FISH. 
 May and June. 
 
 Proteid, 
 Fat, . . . 
 
 Calories, 
 
 Thick Muscle. 
 
 Thin Muscle. 
 
 Total Muscle. 
 
 21-2 
 
 6-8 
 
 20-6 
 10-3 
 
 21-0 
 
 7*7 
 
 150-1 
 
 180-3 
 
 157-7 
 
 July and Aiigust. 
 
 Proteid, 
 Fat, . 
 
 Calories, 
 
 Thick Muscle. Thin Muscle. 
 
 20-6 
 7-1 
 
 150-5 
 
 18-7 
 12-2 
 
 190-1 
 
 Total Muscle. 
 
 20-1 
 
 8-4 
 
 160-5
 
 of the Salmon in Fresh Water. 
 TABLE I. Continued. 
 October and November. 
 
 167 
 
 Proteid, 
 Fat, . 
 
 Calories, . . . 
 
 Thick Muscle. 
 
 Thin Muscle. 
 
 Total Muscle. 
 
 17-5 
 3-1 
 
 16-2 
 6-3 
 
 17-2 
 3-9 
 
 100-6 
 
 125-0 
 
 106-7 
 
 TABLE II. 
 Showing Calories per 100 grins, of flesh of the various groups of fish. 
 
 May and June, 
 July and August, . . 
 October and November, . 
 
 Estuary. 
 
 Upper Water. 
 
 197-0 
 193-0 
 143-4 
 
 157-7 
 160-5 
 106-7 
 
 It will be seen in this : 
 
 1. That the food value of salmon flesh is throughout the season greater 
 when the fish is a fresh run fish, than when it has been some time in 
 fresh water. 
 
 2. That the food value of salmon flesh diminishes as the season, 
 advances, both in estuary fish and upper-water fish. 
 
 3. That the flesh of salmon caught in the higher reaches of rivers, in 
 October and November, is of much less value than other salmon flesh 
 being little more than half the value of the flesh of early estuary fish, 
 and little more than two-thirds of that of earlier upper- water fish. 
 
 Food Value of Entire Fish at different Seasons. 
 
 The total food value of a salmon depends on the amount of flesh in the 
 fish, and on the quality of that flesh. The amount of flesh possessed by 
 a fish depends on the length of the fish and on its muscular develop- 
 ment. These three factors and the resulting food values are shown in 
 the following Table : 
 
 TABLE III. 
 
 Showing Total Food Value of average fish of the various groups offish, 
 expressed as calories. 
 
 
 Estuary. 
 
 Upper Water. 
 
 
 Length. 
 
 Total 
 Weight of 
 Muscle. 
 
 Calories 
 perCent. 
 
 Total 
 Calories. 
 
 Length. 
 
 Total 
 Weightof 
 Muscle. 
 
 Calories 
 percent 
 
 Total 
 Calories. 
 
 May and June, 
 
 75 
 
 2,667 
 
 197 
 
 5,254 
 
 75 
 
 2,477 
 
 158 
 
 3,866 
 
 July and August, 
 
 77 
 
 3,078 
 
 193 
 
 5,940 
 
 72 
 
 2,208 
 
 160 
 
 3,532 
 
 Oct. and Nov.. . 
 
 88 
 
 4,120 
 
 143 
 
 5,892 
 
 73 
 
 1,653 
 
 107 
 
 1,768
 
 168 Investigations on the Life-History 
 
 From this Table it will be seen : 
 
 1 . That the total food value of estuary fish remains nearly constant 
 throughout the year, the poorer quality of the flesh in the later months 
 being compensated for by the larger size of the average fish caught. 
 
 2. That from May to August the total food value of the fish caught 
 in upper waters is about one-third less than that of estuary fish. 
 
 3. That the upper-water fish of October and November are of much less 
 value as a food stuff than any other group of unspawned fish, their value 
 being only one-half of that of the upper-water fish of the earlier months, 
 and one-third of that of the estuary fish.
 
 of the Salmon in Fresh Water. 
 
 169 
 
 III SUMMAEY OF EESULTS. 
 
 17. GENERAL SUMMARY. 
 
 BY D. NOEL PATON, M.D., F.R.C.P. ED. 
 
 A. FACTORS DETERMINING MIGRATION. 
 
 It has been generally assumed that the passage of the salmon from 
 the sea to the river is due to the nlsus generativus. In considering the 
 question it must be remembered that the Salmonidae are originally fresh- 
 water fish, and that the majority of the family spend their whole life in 
 fresh water. Salmo Salar and other allied species have apparently 
 acquired the habit of quitting their fresh- water home for the sea in 
 search of food, just as the frog leaves the water for the same purpose. 
 When, on the rich marine feeding grounds, as great a store of nourish- 
 ment as the body can carry has been accumulated, the fish returns to its 
 native element, and there pefonns its reproductive act. 
 
 That the immigration of the fish is not governed by the growth of 
 genital ia and by the nisus generativus is shown by the fact that salmon 
 are ascending the rivers throughout the whole year with their genitalia 
 in all stages of development (p. 64). 
 
 In fish leaving the sea the ovaries vary from 121 to 1439 grms. per 
 fish of standard length, but the accumulation of solids in their 
 muscles and ovaries together is about the same. 
 
 Solids in Musde and Ovaries of Estuary Fish. 
 
 
 November. 
 (Winter Salmon.) 
 
 May and 
 June. 
 
 July and Aug. 
 
 Oct. and Nov. 
 
 Muscle, - 
 
 2481 
 
 2210 
 
 2270 
 
 1750 
 
 Ovaries,- 
 
 23 
 
 47 
 
 72 
 
 545 
 
 Total, - 
 
 2504 
 
 *2257 
 
 2342 
 
 2295 
 
 * Or including all fish dealt with on p. 83: 
 Muscle, - - 1990
 
 170 Investigations on the Life-History 
 
 The number of male fish examined was too small to allow of general 
 conclusions being drawn. 
 
 In the kelts examined the amounts of solids were per standard fish 
 
 Muscle, - 946-00 
 
 Ovaries, - - 9-28 
 
 955-28 
 
 It would thus seem to be the state of nutrition which is the factor 
 determining migration towards the river ; that when the salmon has 
 accumulated the necessary supply of material It tends to return to its 
 original habitat. 
 
 From May to August probably from November to August the fish 
 leaving the sea have the amount of material stored in their muscles 
 about the same. During these months the ovaries are yet small, and do 
 not act as a reservoir for stored material. In October and November 
 the estuary fish have a smaller amount of stored material in their 
 muscles. Why have these fish not left the sea sooner ? Is it that, 
 either because they have left the rivers later, or because the supply of 
 food has been less readily obtained, the period of rapid growth of the 
 genitalia has supervened before the full accumulation of material in the 
 muscle has been accomplished ? This rapid growth of the genitalia 
 would withdraw material from the muscle and prevent its accumulating 
 there, and thus, when the necessary amount of stored material was 
 accumulated, it would be distributed between the muscles and genitalia. 
 
 The late-coming fish, although the supply of solids in the muscles is 
 smaller, have the ovaries so large that the total store of nutrient 
 material in the fish is just about the same as in those entering the 
 estuaries in the earlier months. 
 
 A return to fresh water is essential for the completion of reproduc- 
 tion, for it has been shown that salt water prevents the development of 
 the ova. In its natural condition the fish is impelled to migrate sea- 
 ward in search of more abundant food, but descent to the sea is not 
 necessary for the development of the genitalia. This is proved by the 
 experiments carried on at Howietoun, which show that fish, when 
 properly fed, may develop their genitalia without leaving fresh water. 
 Again, the salmon of the great American lakes spawn in the streams, 
 and yearly descend to the main lakes, as the salmon of this country 
 descend to the sea, there to feed and lay in the necessary store of 
 material. 
 
 The course of migration and the question of to-and-fro migration 
 have been discussed on pp. 75 to 78, and it has been shown that the early- 
 coming fish press up to the upper waters of the rivers, and that on to 
 August fish continue to stream into the upper reaches ; but that the 
 fish leaving the sea in October and November do not at once ascend to 
 the upper parts of the river. It has been further shown that there 
 is strong evidence against there being a to-and-fro migration from river 
 to sea and sea to river throughout the season. 
 
 B. Do SALMON FEED IN FRESH WATER? 
 
 The question of whether salmon feed while in fresh water has been 
 frequently discussed. Much depends on what is meant by the word 
 "feeding." By feeding, we here mean not the mere swallowing of material; 
 but the digestion, absorption, and utilisation of that material by the body. 
 That salmon take the fly, minnow, or other shining object in the 
 rnouth is no argument as to their feeding in this sense. That they may,
 
 of the, Sidmon in Fresh Water. 171 
 
 and occasionally do, take and swallow worms and other wriggling objects 
 is well known. But the swallowing of a few worms can do but little to 
 make good the enormous changes going on in the fish, even if, when 
 swallowed, they are digested and used. 
 
 The evidence we have adduced may be summarised as follows : 
 
 1st. There is no reason why salmon should feed during their stay in 
 fresh water. When they leave the sea they have in their bodies a 
 supply of nourishment not only sufficient to yield the material for the 
 growth of ovaries and testes, but to afford an enormous supply of energy 
 for the muscular work of ascending the stream (pp. 33, 93, and 120). 
 
 2nd. During the stay of the fish in fresh water the material accumu- 
 lated in the muscles steadily diminishes, and there is absolutely no 
 indication that its loss is made good by fresh material taken as food 
 (pp. 83, 93, and 120). 
 
 3rd. The marked and peculiar degenerative changes which the lining 
 membrane of the stomach and intestine undergoes during the stay of the 
 fish in fresh water shows that during this period the organs of diges- 
 tion are functionless (p. 13). 
 
 The absorption of food stuffs is not a mere mechanical process, but is 
 chiefly dependent on the activity of the cells lining the alimentary 
 canal, and in the river these essential cells degenerate and are shed. 
 
 It is a point of no little interest that before the fish again reaches the 
 sea, after spawning, the lining membrane of the alimentary canal 
 undergoes complete regeneration (p. 17 and 20), while the distended con- 
 dition of the gall bladder seems to indicate that the bile-forming func- 
 tion of the liver is again becoming active. 
 
 4th. The very low digestive power of extracts of the mucous mem- 
 brane of the stomach and intestine, not only in fish from the upper- 
 reaches in which the degenerative changes abovereferred to have occurred, 
 but in fish coming to the mouth of the river and with the lining mem- 
 brane still intact, seems to indicate that the salmon has practically 
 ceased to feed before it makes for the river mouth (p. 23). It is to be 
 regretted that, although every effort has been made, no specimen of a 
 salmon stomach containing food has been procured. It is highly 
 desirable that the digestive activity of such stomachs should be compared 
 with the activity of those examined in this series of observations. 
 
 5th. The changes in the bacteria of the alimentary canal also throw 
 light upon the question (p. 36). Generally speaking both in the 
 estuary and in the upper reaches, the number of organisms varies 
 directly with the temperature of the water. This is just what might 
 be expected, since the number of organisms in the water largely depends 
 upon its temperature. 
 
 But setting this aside, it is found that while in the gullet there is no 
 great difference between the number of organisms in fish in the 
 estuaries and in fish in the upper reaches, there is a markedly greater 
 number of organisms in the stomach and intestine of fish in the upper 
 reaches. This is especially the case with the putrefactive organisms 
 which are the most readily destroyed by free acids. The greater abundance 
 of these in the upper water fish is strongly indicative of the absence of 
 the free acid which is formed in the stomach of fish while digesting food, 
 and which if present would destroy them. 
 
 Miescher concluded that organisms are less numerous in the 
 fish in the upper waters, but his conclusion is not supported by any 
 evidence. 
 
 6th. Our observations confirm these of Miescher as regards the 
 absence of food from the stomach. In not one of the 104 fish sent to the 
 Laboratory during 1896 and the spring of 1897, was any trace of food
 
 172 Investigations on the Life- History 
 
 found either in the stomach or in the contents of the intestine. That 
 this is not due to rapid digestion has been proved. That it is not due 
 to the fish disgorging the contents of the stomach when caught is shown 
 by the absence of any trace of the indisgestible portions of worms, 
 insects, or fish in the intestine. 
 
 To the unscientific mind it is perhaps difficult to realise the possibility 
 of a fast of several months in so active an animal as the salmon. But 
 it must be remembered that it is simply a question of supply of energy. 
 
 The food yields energy for work, but if it is taken in excess, it is 
 stored so as to be available at a future period. It has been shown that 
 in the salmon such storage goes on to an enormous extent, and that, 
 even at the end of the fast, there is still plenty of material available to 
 meet any unexpected call for energy. Nor is the salmon exceptional in 
 this respect. Many other cold-blooded animals have the same power 
 of living for very prolonged periods without taking food, while several 
 warm-blooded animals during the rutting season undergo prolonged 
 fasts. It is stated that the male fur seal, after coming to land, may 
 live for over a hundred days without food. During this period he is 
 constantly engaged in struggles with other males, and he finally leaves 
 the shore in a state of extreme emaciation. 
 
 We have thus no hesitation in confirming the conclusions of Miescher- 
 Ruesch that the salmon, at least before spawning, does not feed during 
 its sojourn in fresh water. 
 
 C. CHEMICAL CHANGES IN THE SALMON IN FRESH WATER. 
 
 It is because of this prolonged fast and because of the important 
 changes going on in the fish during the fast that it affords so interest- 
 ing a physiological study in metabolism. An opportunity is 
 afforded of investigating the manner in which materials are stored in the 
 animal body, the extent to which they may be transferred from one 
 organ to another, the nature of some of the chemical changes they 
 undergo, and the extent to which the various stored materials are 
 utilised as a source of energy in the body. 
 
 /. Solids and Water of Miisde, Genitalia, etc. 
 
 It has been shown that during the sojourn of the fish in fresh water 
 there is a steady loss of solids from the muscles and a steady gain of 
 solids by the genitalia, and it has further been shown that the gain of 
 solids by the genitalia is small compared with the loss of solids from the 
 muscle, that in fact the greater part of the solids lost from the muscles 
 are used for some other purpose than the building up of the genitalia 
 (p. 83). 
 
 As the season advances, the fish coming to the estuaries have 
 a larger percentage of water in the muscle about 6 or 7 per cent, 
 more than the fish leaving the sea earlier in the season. In 
 the upper reaches the flesh throughout the season contains a greater 
 percentage of water than the flesh of estuary fish. In May and June 
 the upper-water fish have about 5 per cent, more water than the 
 estuary fish, and in October and November about 1 3 per cent, more 
 water than the estuary fish of May and June. 
 
 It is this increase in the percentage of water of the flesh which main- 
 tains the weight of the fish per fish of standard length, although the 
 solids as a whole have diminished. 
 
 //. Fats of Muscle, Genitalia, etc. 
 
 Nothing is more extraordinary than the enormous accumulation of 
 fats which takes place in the muscle of the salmon during its visit to the
 
 of the Salmon in Fresh Water. 173 
 
 sea (p. 95). Not only is the tissue between the individual 
 fibres loaded with fat, but, as shown by Mr. Mahalanobis (p. 106), an 
 intrafibrous or interfibrillar accumulation of fat occurs. In the river, 
 as the season advances, this accumulated fat is steadily got rid of by 
 the muscle. There is no reason to suppose that anything of the nature 
 of a degeneration occurs. The 'fat is simply excreted from the muscle 
 to supply the fat of the growing genitalia, or used in the muscle as a 
 source of energy. 
 
 In the muscles the fatty acids are chiefly in the form of ordinary fats. 
 In the ovaries and testes, on the other hand, the fatty acids are largely 
 combined with phosphorus as lecithin. An important decomposition 
 and reconstruction of the fats thus occurs in the growing ovaries. In 
 the ovaries the amount of lecithin is very large, but the amount in the 
 testes is by no means trifling, and the constant occurrence of this sub- 
 stance seems to point to it as the first stage in the formation of nucleins. 
 
 ///. Proteids of Muscle, Genitalia, etc. 
 
 Dr. Boyd's observations (p. 112) indicate that the albuminous 
 materials of the muscle may be divided into two classes : (1) Those 
 soluble in salt solution ; (2) those not soluble in salt solution. He 
 shows that globulin substances constitute nearly the whole of the soluble 
 proteids, and that proteoses and peptones are not present in any circum- 
 stances. He further shows that there is a small quantity of some 
 phosphorus-containing proteid either a nuclein or a pseudo-nuclein 
 among the soluble proteids. It is these soluble proteids which diminish 
 in fish in fresh water. When they are abundant, as in fish at the mouth 
 of the river, on boiling they may coagulate between the flakes of the 
 muscle and form with the fats the characteristic curd. 
 
 Of the insoluble proteids part is composed of white fibrous tissue, 
 part of a phosphorus-containing proteid which may be called myostromin. 
 
 Dr. Dunlop's results (p. 120) show more fully the extent to which 
 proteids accumulate in the muscles, and the rate at which they diminish 
 as the fish passes up the river. The first point of interest is that the 
 proteids do not disappear to anything like the same extent or at the 
 same rate as the fats. As already indicated, it is from the fats that the 
 energy for muscular work is chiefly procured. The second point of 
 interest is that the proteid surplus available for energy that is, the 
 proteid not used in building the ovaries is no greater in the upper water 
 water fish in October and November than in July and August. This 
 seems to indicate that quite early in the season while the ovaries are grow- 
 ing slowly, the proteids disappearing from the muscle are more than 
 sufficient to meet the requirements of these structures, while later in/ 
 the year, when the growth of the ovaries is going on more rapidly, all 
 the proteid disappearing from the muscle is transported to and used in 
 them. 
 
 A further point of interest brought out is that in the male the 
 amount of muscle proteid disappearing from the muscles is so much more 
 than sufficient for the requirements of the growing testes that a very- 
 much larger surplus is available for muscular work in the male than in 
 the female. 
 
 IV. Source of the Energy for Muscidcw Work, etc. (p. 139J. 
 The extent to which the fats and proteids lost from the muscles are- 
 used for the construction of the genitalia on the one hand, and 
 for the liberation of energy on the other, varies somewhat in males and 
 females. Taking the earlier months, to August, it has been shown that 
 in the female 12 per cent, of the fats and 23 per cent, of the proteids go-
 
 174 Investigations on the Life-History 
 
 to the ovaries, the rest being available for energy ; while in the male 
 about 5 per cent, of the fats and 14 per cent, of the proteids go to the 
 testes. 
 
 The total energy liberated from fats and proteids is possibly somewhat 
 greater in the male than in the female, being to August 1,271,000 
 Kgms. per fish of standard length in the female, and 1,380,000 Kgms. in 
 the male. Of the energy thus liberated about 2,200 Kgms. are required 
 to raise the fish to the height of the upper water of the river, the 
 remainder being available for the much greater work of overcoming 
 the resistance of the stream, for internal work and for other calls 
 upon the energy supply. 
 
 Of this total available energy in the female, about 20 per cent, is 
 derived from the proteids, while in the male only 9 per cent, is derived 
 from this source. The rest is derived from the fats. 
 
 f us of Muscle, Genitalia, etc. (p. 
 
 It has been shown that in the female fish only just enough phosphorus 
 is accumulated in the muscle to supply the wants of the growing ovaries, 
 while in the male the accumulation is superabundant. In this connec- 
 tion it has been further pointed out that in the male the enormous 
 growth of the bony jaw may use up a further amount of phosphorus. 
 Whether in the female any phosphorus required for the ovaries in 
 excess of that stored in the muscle is procured from the bones, these 
 observations do not indicate. 
 
 The phosphorus is stored in the muscle chiefly as phosphates, and to a 
 somewhat smaller extent as lecithin. The amount of lecithin in the 
 muscle is not nearly sufficient to yield the lecithin of the ovaries. In 
 the ovaries the phosphorus is in the form of ichthulin, a pseudo-nuclein and 
 lecithin, so the phosphorus from the phosphates of the muscles must 
 undergo profound changes in the growing ovaries, and being synthesised 
 with organic bodies be built into these compounds. That these com- 
 pounds are the forerunners of the still more complex nucleins of the 
 embryo is indicated. In the male the transference of the phos- 
 phates of the muscle into these higher nuclein compounds is even 
 more direct, and the occurrence of lecithin in considerable amount in the 
 growing testes seems to point to this substance as the first step in the 
 synthesis of inorganic phosphates to nucleic acid. 
 
 VI. Iron of Muscle and Ovaries. 
 
 Dr Greig (p. 156) has shown that the ichthulin of the ovary contains iron, 
 and the amount of iron in the ovaries thus increases as the organs grow. 
 Whence is this iron procured ? 
 
 It has been shown that the iron lost from the muscle is insufficient to 
 yield the iron gained by the ovaries, and it is thus probable that the 
 haemoglobin of the blood must be drawn on for this element. The liver 
 does not seem to yield iron to the ovaries. 
 
 VII. Pigments of Muscle and Ovaries. 
 
 Miss Newbigin's study of the pigments of the muscle and ovary (p. 159) 
 shows that two lipochromes are present. First, the very widely dis- 
 tributed yellow pigment the so-called lutein which colours the yolk of 
 the hen's egg ; and second, a bright red lipochrome which, mixed 
 with the former, gives the characteristic colour to the salmon muscle 
 and ovaries. 
 
 Though it has not been possible to investigate the source of the 
 pigments, the evidence adduced tends to show that the characteristic red 
 pigment is probably not derived from the food, but that it is constructed
 
 of the Salmon in Fresh Water. 175 
 
 possibly out of the very widely distributed yellow pigment. Its storage 
 in the muscles and its transference to the ovaries has been demonstrated. 
 Its fate in the male fish is still obscure, though the deeper pigmentation 
 of the skin in the male suggests its elimination by that channel. What 
 the purpose of the pigment is, is not clearly indicated, though it seems 
 probable that by colouring the ova it may assist in their concealment 
 during development. 
 
 VIII. Nature of the Transference of Material. 
 
 On the nature of the transference of material these observations also 
 throw important light. They clearly show that nothing of the nature 
 of a degeneration in the muscle take place. The muscles simply excrete 
 or give out the material accumulated in them. 
 
 Miescher discusses this point at great length. He first considers if 
 what he calls the liquidation and degeneration (Fettentartung) 
 is caused by changes in the nerves. But since he finds no visible 
 changes in the nerve bundles to the muscles he dismisses this possibility. 
 According to his view, the liquidation is caused by deficient respiration 
 in the muscle, due to the deficient supply of blood as a result of the 
 starvation and of the rapidly growing ovaries taking off a Larger and 
 larger amount of blood from the muscles. He supports this view first 
 011 general physiological principles, and secondly, from a consideration of 
 the blood supply to the muscles and ovaries at various periods. 
 
 The theory, however, assumes that the change in the muscle is a 
 degeneration, which it is not, and it affords at best but a partial 
 explanation of the condition. It is too mechanical, and leaves unsolved 
 the problem of what starts the growth of the ovaries, what causes the 
 dilatation of blood-vessels there, and thus leads to the diminished blood 
 supply to the muscles. The growth of the ovaries may be considered a 
 cyclic function, but in all these cyclic functions the nervous system is 
 intimately involved. It is well known that not only is the blood supply to 
 every part of the body under the control of the nervous system, but that 
 the very rate of chemical change in the cells of the body is also under 
 the influence of the nerves. Not only does the brain bring about and 
 control the extensive chemical changes in the muscles which lead to 
 movements, but it also governs the slower chemical changes, such as 
 those by which heat is produced in the warm-blooded animals. The 
 building up and breaking down processes are alike controlled by nerves, 
 and it is only fair to assume that the growth of the ovaries and testes 
 and the discharge of material from the muscle for their growth are primarily 
 determined by the nervous system, and that the vascular changes are 
 secondary and not causal. In this connection it must be remem- 
 bered that throughout the whole period the muscles remain active, and 
 not only excrete material to the ovaries and testes, but also set free the 
 energy of the proteids and fats stored within them, a state of matters 
 irreconcilable with the idea of the existence of a degenerative process. 
 
 The investigation of kelts, though limited in extent, seems to show 
 that, from the period of spawning to the return to the sea, the expen- 
 diture of energy is at a minimun. That many ova remain unshed in 
 the abdomen is clearly shown, and that these ova are absorbed and 
 shrivel up has also been proved. It is thus highly probable that, as 
 indicated by Miescher-Ruesch, the kelt utilises its unshed spawn. 
 We have discovered no evidence that kelts feed. In none of the 
 22 fish examined was there any trace of food in the stomach, or 
 any remains of food in the intestine. On the other hand, a point of 
 very great interest is the regeneration of the lining membrane of the 
 stomach and intestine, and the reappearance of bile in the gall bladder,
 
 176 Investigations on the Life-History of the Salmon in Fresh Water. 
 
 showing that the fish is again becoming capable of taking and using 
 food. 
 
 IX. Food Value of Salmon. 
 
 The food value per unit of weight of muscle deteriorates as the season 
 advances. In each fish caught in the estuaries the food value remains 
 almost constant, the larger size of the late-coming fish making up for 
 the deterioration of the flesh. The food value of each fish caught in the 
 upper waters is less than of those caught in the estuaries, and in 
 October and November is only about one-third that of fish caught in 
 the river- mouth. 
 
 This series of observations is only a contribution to a very large and 
 very interesting subject. Many points yet remain to be investigated, 
 while others touched upon here require extension and confirmation. As 
 regards the course of migration, our investigations cover only a few 
 months of the year, and interesting results are to be expected by 
 extending the investigations into the other seasons. 
 
 We have given evidence to show that the early-coming fish occupy 
 the upper reaches of the river, but a more extended series of investiga- 
 tions is required to show whether the late-coming fish, which during 
 October and November are found in the lower waters, really spawn 
 there, or whether they ultimately pass up to the upper waters. 
 
 Whether the rate of migration can be satisfactorily investigated in 
 our short Scottish rivers is very doubtful. In the great Canadian 
 rivers, such as the Fraser, very valuable results might be expected from 
 the study of this question. Indeed it would be a matter of the greatest 
 importance to have the observations recorded in these papers checked 
 and extended on a large scale in such a river, with its unbounded supply 
 of fish and hundreds of miles of water way. 
 
 The downward migration of kelts requires further study. Of the 22 
 kelts received in April, 1897, all were females. Is this a mere conci- 
 dence, or do the male kelts descend at a different time from the female ? 
 Some of the more important changes in the female kelts have been 
 dealt with, but the interesting question of the loss of the great maxillary 
 development in the male is yet to be elucidated. 
 
 The study of these and many other problems must be left for future 
 investigations. 
 
 GLASGOW : 
 
 PRINTED BY JAMES HEDDERWICK & SONS, 
 FOR HER MAJESTY'S STATIONERY OFFICE.
 
 UNIVERSITY OF CALIFORNIA LIBRARY 
 
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