M'ABCH 26, 1897.] 



SCIENCE. 



495 



gredients of the food, therefore, we have to 

 take into account the amounts of protein 

 and the fuel values. The daily diet used 

 in this experiment was found to furnish, in 

 digestible form, 4.8 ounces of protein and 

 2,960 calories of energy. It may be added 

 that coffee, like tea, contains practically 

 no nutrients, except those of the milk 

 and sugar used with it. 



Taking into account the food and ex- 

 creta it is possible to calculate how much 

 protein or fat the body gained or lost 

 per day during the experiment. In the 

 experiment with the diet referred to, 

 the man's body gained about half an 

 ounce of protein and two and one-tenth 

 ounces of fat per day. This shows that 

 the diet was more abundant than was re- 

 quired for the maintenance of his body. 

 In other words, he was supplied with more 

 protein and fuel ingredients than he re- 

 quired. This was not surprising, since dur- 

 ing the period of the experiment he per- 

 formed practically no muscular work, while 

 his diet had been selected in accordance 

 with his ordinary eating habits when he 

 was engaged in his daily labor. 



In a second experiment with the same 

 man the diet was reduced, mainly by di- 

 minishing the amount of milk from about 

 one quart to one pint per day. The protein 

 was thus reduced to 3.9 ounces and the fuel 

 value of the digested nutrients to 2,650 

 calories. "With this diet the body almost 

 exactly held its own as regards protein, but 

 still gained a small quantity of fat, about 

 half an ounce per day, showing that the food 

 still exceeded the amount needed to supply 

 the wants of the man's body when he was 

 practically at rest. It was calculated that 

 if the amounts of milk, potatoes and butter 

 in his diet had been reduced by one-half 

 the nutrients would have just sufficed to 

 meet his needs under the conditions of the 

 experiment. 



In another experiment, which is the most 



interesting of all, the subject was a young 

 man 23 years of age, rather taller than the 

 laboratory janitor, quite muscular, and 

 weighing 168 pounds without clothing. He 

 had been accustomed for a number of years 

 to school and college life, and later, to the 

 work of an assistant in the college labora- 

 tory. This occupation involved but little 

 muscular activity. Previous experiments 

 had shown that he was inclined to eat 

 rather small quantities of food. His daily 

 diet during the experiment was of his own 

 choosing as in the former case. The food 

 materials were as follows : 



Ounces. 



Cooked beef 3.4 



Mashed potatoes 3.5 



White bread 5.4 



Brown bread 8.8 



Oatmeal 1.5 



Beans 4.3 



Butter 1.6 



Milk 22.9 



Sugar 0.6 



Apples 4.3 



Total 56.3 



The experiment showed that he digested 

 from this food on the average about 3.3 

 ounces of protein and with it enough fats 

 and carbohydrates to malie the fuel value 

 of the digested food 2,500 calories per day. 



The experiment was divided into five 

 periods. During the first period (1^ days) 

 and the fifth (If days) the subject was at 

 rest. He passed more or less of the time 

 in reading, but did nothing to require any 

 considerable exercise of either muscle or 

 brain. The second, third and fourth periods 

 were of 3 days each. During the second 

 period he engaged in severe mental work, 

 partly in calculating the results of experi- 

 ments and partly in studying a German 

 treatise on physics. The third period was 

 one of absolute rest. The subject sat in 

 his chair or reclined upon the cot bed, but 

 did no reading and moved about as little 

 as possible. In the fourth period he per- 



