^ 



438 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [6] 



the same species are very wide, a fact especially noticeable in the 

 oysters 5 and as this is a matter of no little economic interest, I give the 

 results of individual analyses as well as the averages. 



It will be observed that with oysters, clams, &c., the composition of 

 both the flesh (so-called " solids") and the liquid portion of the shell con- 

 tents is given. Other tables have been prepared stating the proportions 

 of flesh and liquids in the edible portion, proportions of edible portion 

 and refuse (shells, &c.) in whole specimens, and numerous other details; 

 but on account of their bulkiness are not inserted here. In the last col- 

 umns of Table YI, however, under the heading " In whole sample," are 

 given the percentages of total edible portion and of total water-free sub- 

 stance in the specimens as received for analysis. Thus, in the last col- 

 umn but two, we have the weight of total edible portion (which includes 

 both flesh and liquids in the oysters, clams, and mussels) in 100 paxts 

 of each specimen. The percentage of refuse, shells, &c., may be found 

 by subtracting the total edible portion in each case from 100. The last 

 column but one gives the percentage of water-free substance (actual 

 nutrients) in each case. This subtracted from the total edible portion 

 will show the percentage of water in the latter. 



As the data of Tables IV and V express the facts only incompletely, 

 I have selected from other tabular statements that have«been prepared 

 for future publication. Tables I, II, III, and IV, which show the re- 

 sults of the analyses of fish more fully, as explained in the appendix, 

 in which several of the larger tables are placed for convenience. 



While, as said above, I do not deem this exposition of the more 

 practical results of the investigation the proper place for discussing 

 its theoretical aspects, I trust it may not be out of piace to speak in 

 somewhat greater length of the relations of the amoui^ts of nitrogen to 

 the amounts of the nitrogen compounds than was done in describing 

 the methods of analysis. 



It was there stated that the amounts of protein, as computed by mul- 

 tiplying the nitrogen by 6.25, differed in some cases very materially from 

 the amounts as computed by subtracting the sum of the ether extract 

 and ash from the whole water-free substance. Or, to put it in another 

 way, the sum of the percentages of osh, ether extract, and protein thus 

 computed, in water-free substance, varied considerably from 100, in sev- 

 eral cases. This is illustrated by the following figures from Table I, 

 which include all those in which the sum of these percentages in water- 

 free substances varies 2 per cent, or more from 100. The variations in 

 the flesh are, of course, less. 



