70 THE PHYSIOLOGY OF PROTEIN METABOLISM 



In one recommendation at least Chittenden is absolutely at fault 

 He recommends a dietary containing 50 grms. of protein and of about 

 2500 calories as sufficient for a soldier doing hard work. This is quite 

 an inadequate diet when judged by the standard laid down by Lieut. - 

 Colonel Melville (278) as the result of observations on soldiers doing 

 hard work similar to that done under service conditions. Melville 

 found that his soldiers did well on a diet containing 190 grms. of pro- 

 tein and of about 3400 calories. " I have no doubt in my own mind," 

 he writes, " that this allowance is ample, and if it errs does so on the 

 side of generosity." But on the other hand he thought that 145 grms. 

 of protein in a diet containing 3500 calories was as low as it was advis- 

 able to go, " and might well be increased especially when hard work is 

 demanded of men under conditions of exposure". But even apart 

 from these practical observations in the field it can be shown by direct 

 estimation and calculation of the amount of work done by Chittenden's 

 soldiers that the 2500 calories were quite inadequate for the work done. 

 The simple fact that some of the soldiers lost as much as 8 '5 kilo- 

 grams in weight during the period of the experiment, which lasted 

 about six months, showed that as the material for the supply of 

 energy was not obtainable from the food it must have been drawn 

 from the subjects' tissues. 



Further, the work of Major McCay (270) on a people the Ben- 

 galis who naturally conform to the so-called Chittenden standard 

 shows that as compared with races which have a higher intake of 

 nitrogen they are of inferior physique, of low endurance and activity, 

 and are not long-lived. 



Chittenden also showed that animals, dogs, fed for long periods 

 on a diet containing a low proportion of protein did not die off sud- 

 denly, but on the contrary thrived. Benedict (59) offered a tren- 

 chant criticism of Chittenden's work in which many facts against the 

 propriety of a low protein intake were pointed out, e.g. those of 

 Haecker, who showed that the resistance diminishes if an animal 

 were kept for a prolonged period on a low protein intake. Two herds 

 of cows, ten in each, were under observation for three years, one herd 

 being fed on a diet containing the normal proportion of protein, and 

 the other on a diet poor in protein. No marked difference was ob- 

 served between the two herds at the end of the second year, except 

 that those on the low protein diet were somewhat less in weight ; 

 during the third year, however, the animals fed on the low protein 

 diet began to fail, and as the animals became so ill the experiment 

 was discontinued. 



