[f)] NUTRITIVE VALIH': OF FISn Ar.J) T^'VERTEBEATES. 437 



nearly so tbiui the inijduct of nitrogen 05' 6.25 would be, and in fact 

 \:irie« but veiy little from tlie exact trutb. For that matter the pro- 

 tein, as ordinarily estimated, would be so near the truth as to make the 

 \ariations of but little practical importance as regards the nutritive 

 values. In the analyses of fresh fish there were no cases in which the 

 sum of water, protein (Nx 0.25), fat, and ash fell below 00, and but three 

 in which it rose above 101 per cent. In the dried fish the variations 

 were of (;ourse wider. 



Fdfs ; ether extract. — The figures for fats denote the amounts dis- 

 soh'ed out by ether and properly denominated ether extract. In the 

 extraction, which is conducted by use of the apparatus described by 

 riohnson,* we find it advisable to repeat the extraction with fresh flasks 

 until weighing of the latter shows no considerable amount of extract 

 rather than to depend upon evaporation of the j^ercolating ether upon 

 a watcli-glass or any other ocular test. The extra.ct is freed from ether 

 l>y heating at 05° C. in a current of hydrogen. I think that the extract, 

 as determined in this way, in the flesh of fish, represents very closely 

 the actual amount of fat. 



jllincyal matters; afiJi. — The ash is determined in the usual way by 

 carboni/ving, extracting with water, incinerating, adding water-extra<'t, 

 drying, and incinerating again. 



TABLES OF ANALYSIS OF FISH. 



The tables show the percentages of water, water-free substance, nitro- 

 gen, albuminoids estimated by difference, as above explained, and ash 

 or mineral matters in the flesh — i. e., edible portion of the fish. The 

 manber of specimens analyzed of each kind is shown in the first column. 

 Where more than one specimen was analyzed the average is given, an<l 

 in case the differences were marked the maximum and minimum per- 

 centage of each constituent is stated. 



Table V gives the comi)osition of the fish, as found in the markets, 

 including both the refuse, bone, skin, entrails, &c., and the edible por- 

 tion. Some of the specimens were entire, others dressed, as indicated 

 in the table by the terms '-whole," "entrails removed," &c. 



From the i)urely economic standpoint this table is the more interest- 

 ing one since it represents the composition of the fish as ordinarily 

 sold, and thus shows the amounts of nutritive materials which peo])le 

 ordinarily receive in return for the money invested. Further state- 

 ments regarding the economical bearings of the figures in the fables 

 will be given beyond. 



ANALYSES OF INVERTEBRATES. 



Table VI herewith recapitulates the principal results of the analyses 

 of 04 si)ecimens of invertebrates (two of vertebrates) belonging to' 11 

 species. As the variations in the coimDOsition of different specimens of 



*Am. Jour. Sci. [H], 1877, 190. 



