96 STORRS AGRICULTURAL EXPERIMENT STATION. 
2. The quantities of nutrients be such as to meet the actual 
needs of the body under the conditions in which the subject 
was placed during the experiment. | 
Meals were eaten three times daily at regular hours, thus 
conforming as far as possible to ordinary custom. Drinking 
water was allowed at all times, the weight used, however, 
being carefully noted. ‘The freedom allowed in the selection 
of diet materially added, we believe, to the success of the ex- 
periment, although the number of different materials, including 
delicacies, made the analyses quite laborious. 
The entire charge of weighing and cooking the food and 
taking of samples for analyses was placed in the hands of one 
individual. Indeed, throughout the whole of our experiment- 
ing the effort has been to have the observers carefully trained 
and unfettered by a multiplicity of duties, and the work shaped 
in systematic routine, in the hope that minor errors, which are 
almost impossible to avoid entirely, might thus be reduced to a 
minimum. 
COLLECTING, PRESERVING AND SAMPLING OF HXCRETORY 
PRODUCTS: 
One desideratum in experiments of this kind is to keep the 
air in the chamber as free from disagreeable odors as possible. 
To this end the feces and urine were collected in receptacles 
provided for the purpose, the receptacles being closed imme- 
diately, and passed out through the food aperture after they 
had come into temperature equilibrium with the air in the 
chamber. It was found that the unpleasant odor could be 
almost instantly destroyed by the use of an ordinary toilet 
‘‘atomizing’’ bottle by which minute quantities of a com- 
mercial preparation, presumably containing eucalyptol, was 
diffused into the air of the chamber. The feces were collected 
as described in the article on Digestion Experiments beyond. 
The collection and preservation of the urine for analysis 
requires especial attention. In these experiments the bladder 
was emptied every morning at six o’clock. All the urine 
voided between that hour and the next morning at the same 
hour was taken as the urine for that day. Each day’s urine 
was carefully weighed, thymol being added as a preserving 
agent. 

