PHYSIOI^OGY— ATWATER, CHITTENDEN, MENDEI.. 259 



Of especial interest is the nitrogen metabolism experiment, in 

 which the total income and outgo of nitrogen was studied with great 

 accuracy with the subject B. A. S. from March, 1905, until April 25, 

 1905, The period began with a fast of 7 daj's, then followed a 

 period of 25 days with food, after which a 4-day fast was made, the 

 experiment finally concluding with a 14-day period with food. 

 This study is of unusual significance in that it showed the rate at 

 which the nitrogenous material lost during fasting is regained by 

 the body. During this period the food eaten by the subject was 

 accurately sampled and analyzed and the nitrogen output in both 

 feces and urine obtained. The series should prove one of the most 

 interesting points in connection with the report. 



Chittenden, Russell H., Yale University, New Haven, Connecticut. 



Grant No. 264. Study of the mi7ihnal protcid requirement of high 



proteid animals. (For previous report see Year Book No. 3, p. 



131.) $2,500. 



Report. — This grant is being used in studying the minimal proteid 

 requirement of healthy dogs — as types of high proteid animals — suf- 

 ficient to maintain the animals in a state of health, body weight, 

 nitrogen equilibrium, etc. In the experiments so far conducted, dogs 

 of different types have been employed, and the effects of a gradual 

 diminution in the amount of proteid food, together with diminution 

 in the amount of non-nitrogenous food, carefully noted. 



Accurate analyses of food and excreta afford data for determin- 

 ing nitrogen balance, so that eventually reliable statistics will be 

 obtained as to the actual amounts of nitrogen per kilo of body-weight 

 and of total calories necessary for the maintenance of bodily vigor. 

 In experiments of this kind the element of time is a very important 

 one, and the real value and significance of the results can not be deter- 

 mined until many months have elapsed. The results so far obtained 

 indicate that the experiments will possess considerable value as afford- 

 ing data of more than ordinary importance in the general subject of 

 nutrition. 



Mendel, Lafayette B,, Sheffield Scientific School, Yale University, 

 New Haven, Connecticut. Grant No. 265. Study of the phys- 

 iology of growth, especially in its chemical processes. ^2,000. 

 Report. — The grant is being used in a study of the chemical com- 

 position of the developing animal body and the equipment of this 

 organism for its nutrition, upon which growth essentially depends. 

 Data are being collected at first hand regarding the composition of 



