54 The Philippine Journal of Science ^22 



per kilogram of body weight (2,090 per 52 kilograms of body 

 weight). Concepcion's data show an intake of 35 calories per 

 kilogram of body weight (1,799 per 52 kilograms of body 

 weight) . Aron and Hocson concluded that when the caloric re- 

 quirement of 1,800 per 50 kilograms of body weight was satisfied, 

 0.16 gram nitrogen per kilogram of body weight was sufficient to 

 establish nitrogen balance. The nitrogen intake of Collado's 

 subjects was 0.18 gram per kilogram of body weight, and that 

 of Concepcion's 0.15 gram. Hence, it is reasonable to assume 

 that the subjects of these two investigators were getting enough 

 nitrogen to prevent loss of this element from the body. 



EXPERIMENTAL 



The following nitrogen-metabolism experiments were con- 

 ducted to find out whether it is possible for Filipinos, who have 

 resided one year or more in the United States and have become 

 accustomed to American diet, to remain in nitrogen equilibrium 

 when given a Filipino food of rice, fish, meat, and vegetables. 

 The subjects, all males and healthy, were four Philippine Govern- 

 ment students taking post-graduate courses at Yale. 



To simplify the analyses and the preparation of the foods, 

 salmon and ham were used as the fish and meat foods, respec- 

 tively, while lettuce, sweet potato, and banana formed the 

 vegetables. The nitrogen was determined in the food as pre- 

 pared for eating, and control determinations were made now and 

 then to guarantee that the nitrogen content of each particular 

 food did not vary too widely. 



Except for the coffee and the little powdered milk and sugar 

 which go with it for the sake of savor, no restriction was made 

 as to the amount of food each subject should take. All were 

 allowed to eat as much as they wanted. To lessen the monotony 

 of the ration, meat and fish were given on alternate days, as was 

 also done with potatoes and lettuce. 



The period at which the actual analyses were made was pre- 

 ceded by a preliminary period of at least three days, during 

 which the actual experimental diet was ingested. Charcoal in 

 gelatin capsules was used for marking the f<eces; the latter was 

 mixed with a little alcohol and hydrochloric acid before drying 

 on the water bath. Thymol was used as a preservative for the 

 urine. The food was purchased and cooked by me. 



Methods used. — The acidity was determined by titration with 

 0.1 N sodium hydroxide, according to Folin's method; total 

 nitrogen, by Kjeldahl's; creatinine, by Folin's colorimetric ; uric 



