CIV REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
of European fishes made by different observers, and the comparison of 
the same with those of American fishes; and changes in the composi- 
tion of oysters by removal from salt to brackish or fresh waters. Part 
II treats of the constituents of foods, their principal nutrients, and the 
way in which those nutrients are utilized by the human body in the 
formation of tissues and for sustaining the vital functions; the digest- 
ibility of fishery products; the relative value of the different species of 
fishes, mollusks, and crustaceans, according to the percentages of their 
component nutrients, the same being illustrated by tabular statements 
and colored diagrams; the objects and results of the floating of oysters, 
and oysters considered as an article of food. 
Without extending these remarks beyond their proper limits it would 
be impossible to give an adequate idea of even the more important 
features of Prof. Atwater’s investigations, but his final conclusions may 
very appropriately be quoted, as they are at least suggestive to all pro- 
moters of fishery matters. They are as follows : 
The chief uses of fish as food are (1) as an economical source of nutriment and (2) 
to supply the demand for variety in diet, which increases with the advance of civil- 
ization and culture. As a nutriment, the place of fish is that of a supplement to 
vegetable foods, the most of which, as wheat, rye, maize, rice, potatoes, etc., are de- 
ficient in protein, the chief nutriment of fish. The so-called nitrogenous extractives 
(meat extract) contained in small quantities in fish, as in other animal foods, are 
doubtless useful in nutrition. 
Late inquiry in agricultural and biological chemistry has brought out some facts 
which emphasize the importance of fish-culture and the greater use of fish as food 
from the standpoints of hygiene and domestic, agricultural, and even national econ- 
omy. Our national dietary is one-sided. Our food contains relatively too much of 
fat, sugar, and starch, and too little of protein. This is a natural result of our agri- 
cultural conditions, which have led to the production of large quantities of maize 
(which is relatively deficient in protein) and of excessively fat beef and pork. Our 
agricultural production is in this sense one-sided. Our soils are becoming depleted 
by culture. The evil results of this are already evident in the older and are becoming 
so even in some of the newer States of the Union. Of the ingredients of plant food 
which are needed for the restoration of fertility, the costliest and scarcest is nitrogen, 
which is the characteristic element of the protein compounds of our food. 
Avery large amount of the waste products which are left from the consumption 
of food, instead of being returned to the soil for restoring its fertility and increasing 
its production, is carried off in drainage waters and through the sewers of the large 
cities into the rivers and sea. The nitrogenous products are thus especially exposed 
to loss. The nitrogen, however, is not lost necessarily in this way. It goes for the 
support of marine vegetation which forms the food of fish. It may thus again be 
utilized as food for man. Fish has relatively less of fats and more of protein than 
meats and vegetable foods. By fish-culture, then, we are enabled to supply the very 
materials which are lacking in our dietaries and from the waste products may be saved 
the valuable fertilizing elements, including phosphorus and especially nitrogen. 
As population becomes denser, the capacity of the soil to supply food for man 
gradually nears its limit. Fish gather materials that would otherwise be inaccessi- 
ble and lost, and store them in the very forms that are most deficient in the produce 
of the soil. Thus, by proper culture and use of fish, the rivers and sea are made to 
fulfill their office with the land in supplying nutriment for man. 
