Dec. 8, 1887.J 



FOREST AND STREAM. 



389 



this country do not believe in taking fish just for the fun 

 Of the slaughter. If they cannot make use of them fresh, 

 preserve them for future use in this manner, and there is 

 nothing much more tasty for a breakfast relish than a 

 piece of smoked salmon cured in the way the fishermen 

 in this country preserve them. 



There is no better salmon fi?bing ground to be had in 

 the Dominion of Canada than the property known as 

 Camp Adams, with its record this past season of 187 

 Salmon— every one of which was killed with the fly— 

 during periods that would not on the whole aggregate 

 over three Aveoks, and never more than three rods fishing 

 at one time, and often not that many. 



On the morrow everything is bustle and confusion. The 

 Falls have to be visited, looks taken of spots, to be borne 

 away as cherished memories, until they can again be vis- 

 ited, perhaps the following year, or perhaps never — who 

 can say? Time will tell its own story. We will wait and 

 watch, hoping that when next the camp is visited none of 

 the merry party, now about leaving it, will have crossed 

 the brink of the great beyond. 



It is late before a start can be made, late when they 

 reach Way's and later still when they reach Newcastle, 

 where after a change of clothing we find our friends look- 

 ing like civilized beings, with the exception of a few fly 

 bites, and the rich brown tan of a ten days' August sun 

 not much the worse for wear. 



In speaking of Roddick on Saturday morning I asked 

 him how he enjoyed the trip. "Well, if I were going to 

 die and could get up to Camp Adams for a week I would 

 be good for two years more, and all the medicine they 

 might give me would not lull me. Two years ago I wasn't 

 worth a cent when I came down here! I went home a 

 well man. I have not been sick since till this spring, and 

 just as soon as I got well enough I left for Miramichi. Now 

 I will go home, and if I get s ck again look out for me, 

 doctors are nowhere alongside of fresh salmon, salt cod 

 fish, pork grease and potatoes and Camp Adams." 



Crawford and Roddick left on Saturday morning, reach- 

 ing St. John in time for Saturday night's boat, arriving 

 in Boston Sunday evening and New York Monday morn- 

 ing, where Reddick taking leave of his companion re- 

 turned to his home in Wilmington, to dream by day and 

 night of the murmuring waters, sporting scenes and 

 pleasant shades around Camp Adams. Salmo. 



Gen. Emory's Whitefish. — "A Washington Angler" 

 writes to the Post of that city: "The death of General 

 W. H. Emory has recalled to my mind a fishing incident 

 which will interest some of your piscatorial readers. It 

 occurred in the spring of 1851 when the General joined 

 his friend. Charles Lanman, on a fishing expedition to 

 the Little Falls of the Potomac, where he captured a 

 101b. rockfish, and, as Daniel Webster had only a fort- 

 night before taken a fish of the same size in the same 

 pool, the General sent his prize to the statesman with his 

 compliments by way of showing that the American army 

 was invulnerable. No fish of that size have been taken 

 in the Potomac with the hook during the last thirty 

 years. " 



Catfish on Troll.— Rochester, N. Y., Dec. 1.— I notice 

 in your issue of November 17 a note of E. A. Black's rare 

 catch wlrile trolling from a canoe. I had the same ex- 

 perience last June fishing on the Bay of Quinte, near 

 Massassaga Point. I was trolling for bass and was thun- 

 derstruck when I landed a 61b. catfish. The troll was 

 caught in the upper jaw near the corner of the mouth. 

 My brother, who was trolling at the same time, thought I 

 had a large bass, as I had to play him some time before I 

 could land him.— F. S. J. 



Address all communimtwns to the Forest and Sti-eam Pub. Co. 



THE CHEMICAL CHANGES IN OYSTERS BY 

 FLOATING. 



BT PHOF. W. O. ATWATEH. 



[Read before the American Fisheries Society.] 

 Concluded from Page 369. 



THE following experiments were made with oysters sup- 

 plied by Mr. F. T. Lane, of New Haven, Conn., a com- 

 munication from whom was just quoted, and for whose 

 courteous aid as well in furnishing the specimens as in 

 giving useful information, I take this occasion to express 

 thanks. 



The oysters had been brought from the James and Poto- 

 mac rivers and ''planted'' in the beds in New Haven Harbor 

 (Long Island Sound) in April, 1881, and were taken for an- 

 alysis in the following November. 



Two experiments were made. The plan of each experi- 

 ment consisted in analyzing two lots of oysters, of which 

 both had been taken from the same bed at the same time, 

 but one had been "floated" while the other had not.. The 

 first specimen was selected from a boat-load as they were 

 taken from the salt water and the second from the same lot 

 after they had been floated in the usual way in brackish 

 water for forty-eight hours. For each of the two experi- 

 ments, Mr. Lane selected, from a boat-load of oysters as 

 they were taken from the salt water, a number, about three 

 dozen, which fairly represented the whole boat-load. The 

 remainder were taken to the brackish water of a stream 

 emptying into the bay and kept upon the floats for forty- 

 eight hours, this being the usual practice in the floating of 

 oysters in this region. At the end of that time the oysters 

 were taken from the floats and a number fairly representing 

 the whole were selected as before. Two lots, one floated and 

 the other not floated, were thus taken from each of two 

 different beds. The f our'lots were brought to our laboratory 

 for analysis. 



The specimens as received at the laboratory were weighed, 

 Thereupon the shell-contents were taken out and the shells 

 and shell-contents both weighed. The solid and liquid por- 

 tions of the shell-contents, i. c, the flesh or "solid" and 

 "liquor" or liquids, were weighed separately, and analyzed. 

 We thus had for each lot the weights of flesh and liquids, 

 which together made the weight of the total sheil-con tents, 

 and the weight of the shells, which with that of the shell- 

 contents made the Aveight of the whols specimens. We also 

 had, from the analysis, the percentage of water, nutritive 

 ingredients, salts, etc., in the flesh and' in the liquids. From 

 these data the calculations were made of the changes which 

 took place in floating. For the details, which are somwhat 

 extended, I may refer to the publications mentioned above. 

 It will suffice here to give only the main results. 



The body of the animal may be regarded as made up of 



water and so-called water-free substance.™ The water-free 

 substance contains the nutritive ingredients or "nutrients." 

 These may be divided into four classes: (1) Protein com- 

 pounds, the so-called "flesh-formers," which contain nitro- 

 gen; (2) fatty substances, classed as fats; (3) carbohydrates; 

 (4) mineral salts.* These constituents of the flesh of oysters 

 have been but little studied. It is customary to assume 

 them to be similar to the corresponding compounds of other 

 food materials, but very probably the differences, if known, 

 might prove to be important. The mineral matters especi- 

 ally, which are very large in amount, appear to include con- 

 siderable of the salts of the sea water. Of the nature of the 

 ingredients of the liquids but little is known. They consist 

 mainly of water and salts, and the amounts of their ingre- 

 dients which are here reckoned as protein, fats and carbo- 

 hydrates, are very small, so that whatever error there may 

 be in classing them with the ordinary nutrients of food, it 

 will not very seriously affect the estimates of nutritive 

 values. 



GE N'EKAL RESULTS OF THE EXPERIMENTS. 



During the sojourn in brackish water both the flesh (body) 

 and the liquid portion of the shell-contents of the oysters 

 suffered more or less alteration in composition. In order to 

 show clearly what the principal changes as shown by the 

 chemical analysis were, some statistics may perhaps be per- 

 missible here. 



CHANGES IN THE COMPOSITION OF THE (BOOY) OF TFIE 

 OYSTERS IN FLOATING. 



1. The changes in the constituents of the body were mainly 

 such as would be caused by osmose, though there were indi- 

 cations of secretion of nitrogenous matters, and especially 

 of fats, which are not so easily explained by osmose. This I 

 will speak of later. 



2. The amounts of gain and loss of constituents which the 

 bodies of the oysters experienced may he estimated either by 

 comparing the percentages found by analysis before and 

 after dialysis, or by comparing the absolute weight of a given 

 quantity of flesh and the weights of each of its ingredients 

 before, with the weights of the same flesh and of it's ingredi- 

 ents after dialysis. For the estimate, by the first method we 

 have simply to compare the results of the analyses of the 

 floated and the non-floated specimens. Taking the averages 

 of the two experiments, it appears that; 



Before After. 



The percentages of Dialysis. Dialysis. 



Water rose from 77.9 to 82.4 



Water-free substance fell from 22.1 " 17.6 



Total flesh 100.0 100.0 



Protein fell from 10.5 " 8.9 



Fat fell from 2.5 " 1.9 



Carbohydrates, etc., fell from .... 6.9 " 5.2 



Mineral salts fell rrom 2.2 " 1.6 



Total water-free substance of flesh. 22.1 17.6 



There was, accordingly, a gain in the percentage of water 

 and a loss of that in each of the ingredients of the. water-free 

 substance. This accords exactly with the supposition that 

 during the floating the flesh gained water and lost salts and 

 other ingredients. 



It will be more to the point to note the absolute increase 

 and decrease in amounts of flesh and its constituents — in 

 other words, the actual gain or loss of each, in the floating. 

 Estimates by this method have been made and explained in 

 the detailed accounts referred to. They make it appear that 

 100 grams of the flesh as it came from the salt water was in- 

 creased by floating, in one specimen to 120.9 and in the other 

 to 113.4 grams. This is equivalent to saying that the two 

 specimens of flesh gained in the floating, respectively, 20.9 

 and 13.4 per cent., or on the average 17.3 per cent, of their 

 original weight. By the same estimates the water-free sub- 

 stance in the 100 grams of flesh before the floating weighed 

 on the average 22. L grams, while that of the same 'flesh after 

 floating weighed 20.6 grams, making a loss of 1.5 grams or 

 6.6 per cent, of the 22.1 granis, which the water-free sub- 

 stance weighed before dialysis. The main results of the two 

 experiments thus computed may be stated as follows: 



In the "floating" of 100 grams' of flesh (body) of the oysters: 



The Weight of Before Dialysis. After Dialysis. 



Water rose from 77.9 grams to 96.6 grams. 



Water-free substance fell from. 23.1 " "20.6 " 



Whole flesh rose from 100.0 " "117.2 " 



Protein was assumed to re- 

 main the same 10.5 " " 10.5 " 



Fat (ether extract) fell from.. 2.5 " " 2.3 " 



Carhohydrates, etc., fell from. 6.9 " " 6.0 " 



Mineral salts (ash) fell from.. 2.2 " " 1.8 " 



22.1 20.6 



Estimating the increase or decrease of weight of each con- 

 stituent in per cent, of its weight before floating: 



Per cent, of 

 original weight. 



The water gained 23.9 



The free- water substance loses 6.6 



The who flesh (body) gained 17.3 



The protein was assumed to neither gain nor lose. 



The fat loses 8.8 



The carbohydrates, etc. , loses 12.5 



The minerals salts loses 15.5 



In brief, according to these computations, the flesh lost be- 

 tween one-sixth and one-seventh of its mineral salts, one- 

 eighth of its carbohydrates, and one-twelfth of its fat, but 

 gained enough water to make up this loss and to increase its 

 whole weight, by an amount equal to from one-seventh to 

 one-fifth of the original weight. 



These estimates are based on the assumption that the 

 amount of protein in the flesh remained unchanged during 

 the floating. It seems probable, however, that the flesh 

 may have lost a small amount of nitrogenous material. If 

 this was the case the actual gain of flesh and of water must 

 have been less and the loss of fats, carbohydrates and min- 

 eral salts, greater, than the estimates make them. But 

 there appears to be every reason to believe, that the error 

 must be very small, and since it would affect all the ingredi- 

 ents in the same i-atio, the main result, namely, that there 

 was a large gain of water and a considerable loss not only of 

 mineral salts, but of fats and carbohydrates as well, can not 

 be questioned. 



CHANGES IN THE COMPOSITION OF THE LIQUID PORTION 

 (LIQUOR.) 



3. The liquids might be expected to receive material from 

 the flesh, and to yield material to the surrounding water. 

 The materials coming from the flesh would be such as the 

 latter parted with by either osmose or secretion. Those 



*The technical terms here used demand perhaps a word of ex- 

 planation. The "water-free substance" is the dry matter which 

 is left when the water has all been driven out. Over three- 

 quarters of the whole weight of the flesh ("solids") of oysters is 

 water, so that the water-free substance makes less than one- 

 fourth of the whole weight as the oysters are ordinarily sold, ?". e., 

 after being floated, the rlesh averages about one-fifth water-free 

 substance. Taking both the flesh ("meat") and liquids ("liquor") 

 together, the oysters as commonly retailed in our markets are 

 about seven-eighths water and one-eighth water-free substance. 

 That is to say, the actual nutritive material in oysters, as we 

 usually buy them, makes on the average just about one eighth of 

 the whole weight. It is worthnoting that this proportion of actual 

 nutriment is very near the same as in milk. 



yielded to the'water would either'eseape by 'diffusion or be 

 washed away when the shells were open' wide enough to 

 allow. What share each of these agencies had in effecting 

 the changes that actually occurred in the liquids, the ex- 

 periments do not and, in the nature of the case, cannot, tell. 

 Comparing the percentage composition of the liquids before 

 and after floating, as shown by the averages of the analyses 

 in the two experiments, it appears that: 



Before After 

 The percentages of Dialysis. Dialysis. 



Water rose from — 94.9 to 95.5 



Water-free substance fell from 5.1 " 4.5 



Total 100.0 " 100.0 



Protein rose from 1.9 " 2.1 



Carbohydrates, &c, rose from 0.7 " 1.1 



Mineral salts fell from 2.5 " 1.3 



The increase in the percentage of water, and the decrease 

 in that of mineral salts are very marked. The quantities of 

 fats (ether extract) are too small to be taken into account. 

 The increase of nitrogen and thai: of carbohydrates, though 

 absolutely small, are nevertheless outside the limits of error 

 of analysis, and must, like those of the salts, represent actual 

 changes in the composition of the liquids. 



The experiments give no reliable, data for the determina- 

 tions of the absolute increase and decrease of the liquids and 

 ( heir constituents, so that it is impossible to say with entire 

 certainty whether there was or was not an actual gain of 

 protein or fats or carbohydrates. It would seem extremely 

 probable, however, that' the liquids received and retained 

 small quantities of these materials from the flesh (bodies) of 

 the animals. 



CHANGES IN THE COMPOSITION OF THE WHOLE SHELL-CON- 

 TENTS, FLESH AND LIQUIDS. 

 4. Comparing the average percentage composition of the 

 total shell-contents before and after floating in the two ex- 

 periments, it appears* that: 



Before After 

 The percentages of Dialysis. Dialysis. 



Water rose from 85.2 to 87.1 



Water-free substance fell from 14.8 " 12.9 



Total 100.0 100.0 



Protein (N. X. 6.25) fell from 6.8 to 6.5 



Fats (ether extract) fell from 1.4 " 1.2 



Carbohydrates, etc.. fell from 4.3 " 3.7 



Mineral salts (ash) fell from 2.3 " 1.5 



Total water-free substance 14.8 12.9 



After so much detail, I ought perhaps to simply sum- 

 marize the results in a few words and close. But one ortwo 

 matters call for brief notice. 



If the changes in composition of the oysters in floating 

 were due to osmose or dialysis alone, we should expect 

 simply a gain of water and loss of salts (and perhaps of 

 carbohydrates). But the flesh seems to have lost a little 

 carbohydrates and fats and probably protein also, along 

 with the salts, while it was absorbing water. A way in 

 which this may have, come about is suggested by my 

 colleague, Prof. H. W. Conn, who calls attention to the fact 

 that some mollusks, when irritated, produce an extremely 

 abundant secretion of mucus or "slime," so much, indeed, 

 as to sometimes render a small quantity of water in which 

 the animals may he confined, quite sensibly gelatinous. He 

 suggests that the change to fresh water may, indeed, induce 

 such a secretion of mucous and perhaps of carbohydrates 

 and fats as well, which would account for the increase of 

 these substances in the liquids. The observation of oyster 

 dealers that water always thickens the natural juices that 

 adhere to the surface of the oyster and makes it slimy, 

 accords with Prof. Conn's statement. 



If such secretion did take place, the flesh must probably 

 have lost a little protein during the floating. The estimates 

 of absolute gain and loss of weight of flesh and ingredients 

 (see detailed accounts of the experiments) are based upon the. 

 assumption that the quantity of protein was unaltered in 

 floating. If protein w r as given off, therefore, the estimates 

 are wrong. But the quantity of protein secreted and the 

 consequent error must be, at most, very slight. If there is 

 an error its effect would be to make the quantities of nutri- 

 ents after floating appear larger than they really were. In 

 other words, if the error was corrected it would make the 

 loss of nutritive material in floating greater than it appears 

 to be in the figures above given. As explained in the de- 

 tailed report above referred to, I have assumed that the 

 changes due to the ordinary processes of metabolism would 

 be to small too materially affect the results. 



The experiments might have been so conducted as to de- 

 cide this question. It w r ould have been necessary to simply 

 take a larger number in each lot before and after floating 

 and be certain that the number, weight and bulk were the 

 same in the floated and not-floated lots of each experiment. 

 For instance, we might, in each experiment, carefully select 

 two lots of, say a bushel, each, as taken from the beds, have 

 the number of oysters the same in each bushel as an addi- 

 tional assurance* that the two lots were alike, float one bushel 

 and weigh and analyze both. A few experiments of this 

 sort made under different conditions of time, temperature, 

 kind and age of oysters, etc., would give reliable and 

 valuable data. Unfortunately the means at my disposal 

 did not permit so thorough experimen ts. I am persuaded, 

 however, that the results of such series of trials, if they 

 could be made— and I wish they might be — would be very 

 similar to those of the trials here reported. 



It is very interesting to note that these processes which we 

 have been considering in the body of oysters are apparently 

 very similar to processes which go on in our own bodies, 

 namely those by which our food, after it is digested, finds its 

 way through the walls of the stomach and other parts of the 

 alimentary canal into the blood, to be used for nourishment. 

 Physiologists tell us that the passage of the digested mater- 

 ials through the walls of the canal is in part merely a physi- 

 cal action, due to osmose, but that it is in part merely* de- 

 pendent upon a special function of the organs. In like 

 manner the changes in the composition of the oyster, if the 

 above explanation be correct, are caused partly by osmose, 

 and partly by special secretive action, the cell walls and 

 outer coating" of the body of the oyster corresponding to the 

 walls of the alimentary canal of the human body. 



CONCLUSIONS. 



The main points presented in this paper may be very briefly 

 summarized thus: 



In the floating of oysters for the market, a practice which 

 is very general and is also used for other shellfish, the ani- 

 mals are either taken direct from the beds in salt water and 

 kept for a time in fresher (brackish) water before opening, 

 or water added to the shell-contents after they are taken out 

 of the shell. 



When thus treated, the body of the animal takes up water 

 a.nd parts with some of its salts; and small quantities of the 

 nutritive ingredients escape at the same time. The oysters 

 thus become more plump and increase considerably in bulk 

 and weight. But the quantity of nutritive material, so far 

 from increasing, suffers a slight loss. 



In the experiments here reported, the increase in hulk and 

 weight amounted to from one-eighth to one-fifth of the 

 original amounts. This proportion of increase is about the 

 same as is said to occur in the ordinary practice of floating 

 or "fattening" for the market. According to this, five 

 quarts of oysters in their natural condition would take up 

 water enough in "floating" to increase their bulk to nearly 



