CONCERNING LOW PROTEIN DIETARIES 141 



to be ascribed mainly to non-hygienic conditions, or to a lack 

 of care and physiological good sense in the prescription of a 

 narrow dietary not suited to the habits and needs of this class of 

 animal. 



Chittenden's experiments on dogs were carried out under the 

 most favourable circumstances to insure the successful issue of 

 the investigation. The animals were nursed and tended in the 

 most painstaking manner, and every source of danger was 

 guarded against. It must be acknowledged that he has accom- 

 plished what no previous experimenter had been able to do 

 viz., maintain dogs in fair health and keep them alive for varying 

 periods of time over six months on dietaries providing less than 

 2 grammes of protein and 80 calories of fuel value per kilo of 

 body weight. 



As an example of the thorough and whole-hearted methods 

 Chittenden has made use of throughout all his researches on 

 nutrition, nothing he has done shows more clearly his infinite 

 capacity for taking pains than the prolonged experiments 

 devised and carried out with such scrupulous care on these dogs. 

 However, even his methods and results in this experiment have 

 been unfavourably criticized. It has been pointed out * : 



1. He proves too much, for in several instances, as the nitrogen 

 and fuel value of the diet per kilo of body weight became re- 

 duced during the course of the experiment, his dogs actually 

 increased in weight. No. 5 dog increased from 15-5 to 20 kilos 

 on reduction of the nitrogen from 0-54 to 0-26 gramme, and the 

 fuel value from 87 to 65 calories per kilo of body weight. It 

 almost appears as if nitrogen in the diet were entirely super- 

 fluous. 



2. No notice is taken of the build and shape of the animal, 

 although the body surface, and consequently the amount of heat 

 lost by radiation, must have varied enormously. 



3. The kind of dog is not specified, which is a point of great 

 importance, as different kinds of dogs are habituated to different 

 kinds of diet. Some dogs get practically no meat ; others, like 

 the coursing greyhound, are trained on the best beef and mutton. 



4. They led a placid and cloistered existence. For ten days 

 in each month they lived in the metabolism cage, and for the 

 remainder of the time practically in kennels. 



5. Not until a pack of foxhounds have got satisfactorily 

 through a winter's work on Chittenden's reduced diet can his 



* Sir J. Crichton-Browne, " Parsimony in Nutrition." 



