CHEMICAL COMPOSITION OF FOOD-FISHES. 
It would seem from the figures in Table xix that the northern oy 
are, on the whole, richer in nutritive material than the southern 
more analyses are needed to show the true average ranges of variauun. 
One reason why the Virginia oysters appear to disadvantage here may 
be that they were younger. It appears that as the oyster grows older, 
at least up to a certain time, not only do the proportions of flesh and 
liquids increase more rapidly than the shells, but the proportion of 
natural nutrients in the edible portion increases also ; that is to say, 
100 pounds of young oysters in the shell would appear from these 
analyses to contain less of flesh and of liquids than 100 pounds of older 
ones, and when both have been shucked a pound of shell contents 
from the older animals would contain more nutriment than a pound 
from the younger. I wish, however, to be very careful in making these 
statements, because the number of examinations is too small to warrant 
very definite generalizations; indeed, the only figures which bear directly 
upon this especial point are those for the oysters transplanted from the 
James and Potomac Eivers to New Haven Harbor in the spring and 
taken out in the following fall or winter. These show a notable increase 
during this period, both in the quantities of shell contents in a given 
weight of shell and in the amount of actual nutriment in a given weight 
of shell contents. Perhaps this change is more a matter of feeding and 
fattening than of age. However it may be, it is not unnatural that 
changes of this kind, which take place in other animals, should occur 
in the oyster. Thus calves and pigs in growing and in fattening in- 
crease in both the proportion of meat to bone and in the proportion of 
nutritive material in the meat. As regards shellfish, this particular 
point especially demands more extended study. 
The figures of Table xix show a slight difference between the average 
, composition of the edible portion of the oysters taken from the shell in 
the laboratory and that of those purchased out of the shells, in the form 
commonly called “solids” in the markets. Whether this difference is 
accidental or due to the fact that as they are ordinarily shucked for 
sale less of the liquids is saved than was done in preparing our speci- 
mens for analysis, it is impossible to say. 
Table xix is somewhat complex, and calls for further explanation. The 
specimens of oysters are arranged according to locality, from Buzzard’s 
Bay, Massachusetts, to the James Biver, Virginia. The proportions of 
water, protein, fat, and mineral matters in the flesh and in the liquids 
are given separately. The proportions of carbohydrates are not stated, 
since they are not directly determined by the analysis, but are estimated 
by subtracting the sum of the protein, fat, and ash from the total water- 
free substance, which latter is determined along with the percentage 
of water, and is the difference between the latter and 100. Details of 
the methods of analysis may be found in Part I. 
The last two columns of the table, it will be observed, give the per- 
centages of total edible portions and of total nutrients in the edible 
