164 THE BREEDING OF ANIMALS 



Group three (Plate VII, lower) was limited markedly in 

 the amount of food which the animals were permitted to 

 consume. The scant ration given to group three did not 

 prevent the animals from growing, but it did prevent the 

 animals from making a normal growth, and prevented the 

 normal deposition of fat within the body tissues, which 

 seems to be a favorable factor in inducing healthy growth 

 and development. 



The illustrations represent typical animals in the three 

 groups. These illustrations give a general impression 

 of the changes in body form which are readily apparent 

 to the eye, resulting from the methods of treatment of 

 these various groups. 



154. Influence of the amount of food on body weight. 

 A record of the changes in the body weight of an animal 

 is not the most accurate measure of the influence of any 

 environmental factor, but it is sometimes very useful, 

 and often the best measure available. In this experi- 

 ment, animal 501, which was fed for forty-seven months 

 on a full ration, attained in that time a total weight of 

 1965 pounds. Animal 512, fed a medium ration for 

 forty-eight months, attained a weight during that period 

 of 1224 pounds. Animal 500, belonging to the low-fed 

 group, weighed, at the end of the forty-eight months' feed- 

 ing, 1042 pounds. The differences observed in these 

 animals must be due entirely to the differences in the 

 amount of food supplied, as they were subjected to iden- 

 tical conditions in all other respects. The experiment 

 would have been still more valuable if the animals in the 

 three groups had been fed on the different rations from 

 birth. As a matter of fact, the animals in all the groups 

 were generously fed during the first five months of their 

 lives. 



