METABOLISM 5 



If Chittenden be right, there can be no doubt of the 

 far-reaching effect of his views ; our dietary standards 

 would have to be revised, and vegetarianism would 

 become, not only uninjurious, but a system highly to be 

 commended on grounds alike of humanity, hygiene, and 

 economy. To consume a superfluous quantity of such 

 an expensive food constituent as protein is certainly not 

 only wasteful, but, from the great amount of work re- 

 quired for its digestion and the excretion of its end- 

 products, physiologically injurious as well. Chittenden, 

 indeed, is of opinion that many of the degenerative 

 diseases of later life, as well as many of the paroxysmal 

 neuroses, such as migraine, met with in younger 

 patients, are directly due to a luxus consumption of 

 protein. 



Notwithstanding the apparently convincing nature of 

 Chittenden's experiments, it will be well for the physician 

 to be cautious in applying their results in practice. It 

 is all very well for the physiologist to dismiss con- 

 temptuously the universal practice of mankind as having 

 been arrived at purely empirically, and as affording no 

 basis on which to establish rational rules of diet ; but the 

 practical physician, whose art has taught him the safety 

 of a wise empiricism, cannot so lightly discard a rule 

 which has been adopted semper et ubique et ab omnibus. 



even the Voit standard is too low. If, on the other hand, he is to 

 take only the same amount of protein in proportion to the total 

 energy value of his diet as the child, then Chittenden's standard is 

 correct. It is true that the child is constantly laying up protein in 

 the body in the form of new tissue, but against this has to be set 

 the fact that the destruction of tissue in the adult is greater, owing 

 to the performance of muscular work. 



