PART II. 
NUTRITIVE VALUES OF FOOD-FISHES, MOLLUSKS, AND 
-CRUSTACEANS. 
1. INTRODUCTION ; EXPLANATIONS. 
For those who are not familiar with the newer teachings of chemistry 
and physiology and their application in judging of the nutritive values 
of the fishes and invertebrates of which analyses are given in detail in 
Part I and recapitulated in the pages beyond, a few words of explana- 
tion of some of the later results of experimental inquiry regarding 
foods and their uses in nutrition may not be entirely out of place here. 
The statements which follow are in part condensed from articles by the 
writer in the Report of the Oyster Investigation and Shellfish Commis- 
sion of New York, for 1887, by E. (1. Blackford, commissioner, and in 
the National Medical Dictionary, edited by Dr. J. S. Billings, U. S. A. 
If the reader will take the pains to notice the next piece of beef that 
he has to carve for dinner, he will, of course, notice first of all that, 
along with the meat which is good to eat, there is more or less bone, 
which, except in so far as it may be used for soup, is of no value for 
food. The beef, then, may be regarded as consisting of edible portion 
and refuse. The same is true of fish. In eggs there is a correspond- 
ing distinction between shells and the so-called “ meat,” and oysters 
and other shellfish in like manner include the shells, which are simply 
refuse, and the shell contents which make up the edible portion. The 
inside of the potato and the wheat flour are the edible portion, and the 
skin and bran are refuse of potatoes and wheat. 
If we take the beef and separate the meat from the bone, cut it into 
fine particles and keep it for a long time in a hot oven it wm be grad- 
ually dried, that is to say the water will be driven out of it and the so- 
called nutritive substance will remain. In the same way the flesh of 
fish, oysters, milk, eggs, potatoes, and flour are found to consist of 
water and nutritive material. In estimating the values of these differ- 
ent materials for food we leave the refuse and the water out of account 
and consider only the nutritive ingredients. 
We may take a piece of beef, and after cuttingout the bone and drying 
the meat put the latter in the fire and burn it. Nearly all will be con- 
sumed, but a portion will remain as ashes. An operation of this sort is 
H, Mis. 274 52 817 
