August 4, 1905.] 



SCIENCE. 



131 



study has finally been carried out by Chit- 

 tenden through experiments, first on him- 

 self, and then on groups of men engaged 

 in various occupations. In the first of 

 these remarkable experiments, which have 

 recently been described in book form under 

 the title 'Physiological Economy in Nutri- 

 tion' the distinguished Yale scientist de- 

 termined in his own case how far he could 

 safely reduce the protein of his diet and 

 still retain the body in nitrogen equilib- 

 rium. To do this close watch was held 

 on the food and excreta through a year, 

 November, 1902, to October, 1903, and 

 under varying external conditions of work 

 and temperature. As a result of these 

 systematic tests Chittenden found that he 

 could live very comfortably, and in perfect 

 health, on a diet containing 35 to 40 grams 

 of protein daily, with fats and carbohy- 

 drates sufficient to yield 1,500 to 1,600 

 calories. These valuable personal experi- 

 ments were regarded as preliminary only. 

 Later, systematic observations were made 

 with three groups of men, the work being 

 carried through periods of five to nine 

 months for each group. 



The first group comprised colleagues of 

 the author of the experiments, Yale pro- 

 fessors and instructors. The average pro- 

 tein metabolism here was about 46 grams. 

 The second group was composed of soldiers 

 from the hospital corps of the United 

 States army who were detailed for the 

 purpose of the study. Of the twenty who 

 began, thirteen followed the tests through 

 the whole period of over six months. 

 Those who deserted, or were dropped, had 

 much to say through the newspapers about 

 starvation diet, but this was a curious mis- 

 nomer, since, as the records show, the men 

 who remained were kept in perfect nitro- 

 gen ecjuilibrium and found themselves in 

 far better physical condition at the end of 

 the experiments than at the beginning. 

 Through all this time they had plenty of 



work to perform, with constant and rather 

 severe requirements on the muscular sys- 

 tem. The average protein consumption 

 daily was not far from 55 grams. 



Finally, eight Yale athletes showed 

 themselves willing to work through the 

 training and competing season on the re- 

 stricted protein diet. The results here 

 were equally remarkable, in fact probably 

 the most remarkable, as the work done by 

 these men was of a character to call for 

 very high protein diet according to all of 

 our old standards. The experiments were 

 carried out through a period of five months, 

 February to June, 1904, and through the 

 last two months a very close record was 

 kept of diet, excretion, weight and vari- 

 ous other factors concerning the men. 

 Through this sixty-day period, when the 

 muscular exertion was, perhaps, the most 

 taxing, protein equilibrium was maintained 

 on an average of 8.81 grams of nitrogen 

 metabolized for each man daily, corre- 

 sponding to about 55 grams of protein. 

 All these men took high rank in athletic 

 work, several of them being prize winners. 

 The reproductions of photographs, pub- 

 lished in the book, show them to be men 

 of excellent physique, and even of remark- 

 able muscular development in some cases. 

 While the protein diet of these men was 

 low the fat and carbohydrates were gen- 

 erous but not excessive, the calorific value 

 of the whole being seldom over 3,000 

 calories. 



For all these men under examination in 

 these three sets of tests, professional men, 

 soldiers, athletes, complete statistics for 

 each day are published, from which the 

 reader may derive the fullest possible in- 

 formation. Painstaking accuracy is evi- 

 dent in every page, and from the stand- 

 point of logical requirement in experi- 

 mental proof the tables meet any reasonable 

 objection. 



This Chittenden investigation then must 



