

DEMANDS OF THE BODY FOR NOURISHMENT. 143. 
welfare. Part of this larger information may be had from 
metabolism experiments. For the rest we must go outside of 
the respiration apparatus and outside of the laboratory and 
make the observations on a larger scale with people under the 
usual conditions of life. 
2. Special feeding experiments with individuals and with 
groups of people under ordinary conditions. These should be 
planned for the study of specific questions and continued 
through long periods, months or years. ‘hose with groups 
can be made where large numbers of people eat together, as in 
boarding houses, charitable and penal institutions, and the 
army and navy. Such experiments have been carried on with 
success, and more are greatly needed. 
3. Dietary studies. Another way of getting the larger 
knowledge is by studies of the amounts and composition of 
- food eaten by people in ordinary conditions of life. The obser- 
vations should include not only the character and cost of diet 
but housing, clothing, occupation, producing and earning ca- 
pacity, health, intelligence, general scale of living and material 
and moral welfare. In this way much has been learned and 
far more can be learned of the influence of diet as a factor of 
the welfare of the individual, the family, and the community 
at large. 
Such observations need to be made not only with people of 
different classes and conditions of life in this country but in ~ 
other countries also. Rightly carried out they would amount, 
indeed, to the study of the comparative nutrition of mankind. 
I venture to suggest that the time is ripening, if not already 
ripe, for cooperative inquiry of this kind in different parts of 
the world. 
Asa means of promoting such inquiry as well as an aid to 
the utilizing of the results already obtained, an important need 
is a compilation of the results of investigations of the character 
and composition of food materials, dietary studies, digestion 
experiments and metabolism experiments already made in dif- 
ferent countries. ‘his is a task of considerable magnitude, 
but a beginning has been made in connection with the nutri- 
tion investigations of which the metabolism experiments here 
reported form a part, and it is hoped that the enterprise may 
be gradually pushed to reasonably successful completion. 
