OCTOBEB 13, 1905.] 



SCIENCE. 



465 



These experiments, however, were not con- 

 fined to an individual or even to a single 

 group of individuals. Similar experiments 

 were made on other professional men, on stu- 

 dent athletes in training, and on soldiers 

 under military regimen. The nitrogen in the 

 urine was determined daily in twenty-six in- 

 dividuals for periods extending from five to 

 nine months. 



Summarizing the results obtained in all 

 these groups of individuals, it is established 

 that a diet containing about fifty grams of 

 proteid (8 grams of nitrogen) is able to main- 

 tain the adult body machine in perfect repair. 



The professional group alleged a greater 

 keenness for its work, the athletic group won 

 championships in games, and the soldiers 

 maintained perfect health and strength, many 

 professing repugnance to meat when allowed 

 it after five months of practical abstinence. 



Although it is possible that the alleged im- 

 proved mental condition may have been due to 

 mental suggestion, still the fact remains that 

 it has been absolutely proven by Chittenden's 

 work that the allowance of proteid necessary 

 for continued health and strength may be 

 reduced for many months to one half or less 

 what the habit of appetite suggests. 



The reviewer would, however, remark that 

 it still remains to be proven that the fifty 

 grams of proteid in the diet — which is not 

 greater than the body would metabolize in 

 starvation — is advisable as a program for the 

 whole of one's adult life. It may also be that 

 naore than this quantity is indicated, during 

 convalescence from wasting disease, or during 

 the muscular hypertrophy which accompanies 

 preliminary training f or^ muscular effort. 



The reviewer believes that Professor Chit- 

 tenden has fallen into error in the commenda- 

 tion of 2,500 to 2,600 calories as an ample 

 energy content for' the diet of a soldier at 

 ■drill. Accurate information on this point is 

 only obtainable through respiration experi- 

 ments. Chittenden, pursuing a sedentary life, 

 prescribes 2,000 calories for himself or 35 

 calories per kilogram of body weight, while 

 Mendel requires 2,448 calories or 35.3 calories 

 per kilogram. These are entirely normal val- 

 ues for people at light work. In the earliest 



calculations of Voit in 1866 it was shown that 

 a man of 70 kilogTams on a medium mixed 

 diet produced 2,400 calories, or 34.3 calories 

 per kilogram. Rubner allows 2,445 calories 

 to men of 70 kilograms weight engaged in oc- 

 cupations involving light muscular work, men 

 such as writers, draughtsmen, tailors, physi- 

 cians, etc. 



But the soldiers under Chittenden exercised 

 for two hours in the gymnasium, then appar- 

 ently drilled for one hour, and walked for 

 another hour. This physical work can only 

 be accomplished at the expense of increased 

 metabolism. Zuntz has shown that to walk 

 2.7 miles in one hour along a level road re- 

 quires an extra metabolism equivalent to the 

 liberation of 159.2 calories in a well-trained 

 man weighing 70 kilograms. If a soldier 

 during four hours of exercise actually accom- 

 plished the equivalent of work of a walk of 

 ten miles over and above what Professor Men- 

 del accomplished in his laboratory, then the 

 metabolism of the soldier would be larger than 

 Professor Mendel's by 637 calories (159.2 X 4) 

 or he would have had a total metabolism of 

 3,085 calories (2,448 + 637). This does not 

 seem an improbable amount. 



For ordinary laborers working eight to ten 

 hours a day, such as mechanics, porters, join- 

 ers, soldiers in garrison and farmers, 3,000 

 calories, as advocated by Voit, is apparently 

 not too great. Eubner's diet for the same 

 class calls for 2,868 calories. Chittenden's 

 allowance of 2,500-2,600 seems to the writer 

 too small, while Atwater's of 3,400 appears 

 excessive. 



Unstinted praise for painstaking endeavor 

 and unremitting toil belongs to the workers 

 who have achieved this volume. It is a monu- 

 ment of fidelity and an inspiration to thor- 

 oughness in scientific work. 



Graham Lusk. 



University and Bellevue Hospital 

 Medical College. 



The Insulation of Electric Machines. Turner 

 and HoBART. Pp. vi + 297. 146 illustra- 

 tions. New York, The Macmillan Com- 

 pany. 1905. Price, $4.50. 

 It is a difficult and tedious task to write a 



