THIRTEENTH ANNUAL MEETING. 173 
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protein of his food, provided it pleases his palate. But to the 
humble housewife whose husband earns but $500 a year, it isa 
matter of great importance, and she is very apt, after hesitating 
at the dry-goods store between two pieces of calico for her 
daughter's dress, and taking one at ten cents a yard for econ- 
cmy’s sake, though the one at eleven was prettier, to goto the 
grocer’s, the butchers, or the fish-dealer’s, and pay a dollar a 
pound for the nutrients of her children’s food, when she might 
have obtained the same ingredients, in forms equally whole- 
some and nutritious, for fifty or even twenty cents. She will 
continue this bad economy until she obtains a general idea of 
the actual cheapness and dearness of foods, as distinguished 
from their price. 
A pound of lean beef and a quart of milk both contain about 
the same quantity, say a quarter of a pound, of actually nutri- 
tive material. But the pound of beef costs more than the quart 
of milk and it is worth more as a part of a day’s supply of food. 
The nutritive materials or nutrients, as we call them, in the 
lean meat, though the same in quantity as in the milk, are dif- 
ferent in quality, and of greater nutritive value. Among the 
numerous branches of biological research, one, and by no means 
the least interesting and important, is the study of foods and 
nutrition. Within the past fifteen years especially, a very large 
amount of scientific labor has been devoted to the investigation 
of the composition of foods and the function of their ingredi- 
ents in the animal economy. Indeed, very few persons this side 
of the Atlantic have any just conception of the magnitude of 
this work and its results. And, though the most important 
problems are still unsolved, and must, because of their complex- 
ity, long remain so, yet enough has been done to give us a toler- 
ably clear insight into the processes by which the food we eat 
supplies our bodily wants. 
The bulk of our best definite knowledge of these matters 
comes from direct experiments, in which animals are supplied 
with food of various kinds, and the effects noted. The food, 
the excrement, solid and liquid, and in some cases the inhaled 
and exhaled air, are measured, weighed and analyzed. Many 
trials have been made with domestic animals-—horses, oxen 
