132 REPORTS 01^ INVEISTIGATIONS AND PROJECTS. 



When the effect of the ingestion of a specific nutrient or article of diet 

 is to be studied, the plan of the experiment is altered in only one particular — 

 i. e., immediately after entering the respiration chamber the subject is re- 

 quested to eat as much as possible of the material to be studied. The food 

 is usually consumed in a few minutes without unusual muscular effort, and 

 as soon as the calorimeter is in temperature equilibrium the series of 2-hour 

 observations begins. Generally four 2-hour periods constitute an experiment, 

 though at times the observations may be continued for 12 to 15 hours, due 

 care being taken in all cases not to fatigue the subject with the long-enforced 

 muscular rest. The various measured factors can then be compared with 

 those obtained under the conditions of fasting. 



Obviously, according to this plan it is possible to determine with considera- 

 ble accuracy the effect of the ingestion of varying amounts of nutrients upon 

 body weight and temperature, pulse and respiration rate, the elimination of 

 carbon dioxide and water-vapor, the consumption of oxygen, and the heat 

 production, and thus throw important light on the question of the work of 

 digestion. 



The experiments are still in progress and the results of those already made 

 have not been wholly computed ; hence any detailed discussion would be pre- 

 mature, but it may be said that the ingestion of food of any kind results in 

 an increased metabolism as shown by the measurements of the factors men- 

 tioned above. Marked differences in the effect of the ingestion of protein 

 fat or carbohydrate are also noted. 



The nature of the increase in metabolic activity is not yet wholly clear. 

 Probably all the various factors, such as increased motility of the digestive 

 tract, glandular activity in secreting digestive juices, the chemical action of 

 ferments in inducing hydrolysis, etc., contribute to the total effect. Certainly 

 innumerable problems of vital interest to the physiologist as well as the 

 physician await study. 



During the past year two 24-hour experiments and forty-three 8-hour 

 experiments, all with healthy men, were made. These experiments supple- 

 ment the work of the previous year, and while the subject has not as yet 

 been adequately studied, the research must necessarily be interrupted for a few 

 months until the apparatus in the new laboratory is constructed and tested. 



The investigations the past year have been somewhat hampered by the 

 innumerable details incidental to closing out the experimental work in the 

 chemical laboratory of Wesleyan University at Middletown, where it has 

 been in progress for many years, formerly under the direction of Prof. W. O. 

 Atwater and in late years under my direction. The research has been fostered 

 by the U. S. Department of Agriculture, the Connecticut (Storrs) Experi- 

 ment Station, Wesleyan University, and in recent years liberal grants from 

 the Carnegie Institution of Washington have made possible a large amount 



