NUTRITION AND GROWTH: I. 21 



Dog B, with a more than ample diet, became somewhat larger and much 

 fatter, and increased in weight from about 5,500 to 7,000 grams. 



The experiment was continued in this way to the three hundred and 

 fiftieth day, when another photograph (Plate II) was taken. At the 

 same time the animals were measured. (See Table 12.) On comparing 

 the photographs of the dogs taken on the two hundredth and the three 

 hundred and fiftieth day, it is apparent that during these last five 

 months dog A had not only kept its body weight constant, but also 

 had not grown. 



Both animals were more than one and one-fourth years old at this 

 time, and had reached the age at which dogs usually cease to grow. 

 This is proved by the fact that dog B in spite of its ample diet showed 

 no further increase in size and only ver)^ little in weight. 



If the animals (A and B) had been killed at this time the increase 

 or decrease in weight of the different organs and parts of the body since 

 the forty-fifth day, as compared with the body of the control dog D, 

 could have been determined exactly. We would then have had further 

 evidence bearing upon the question as to which organs or parts of the 

 body increase at the expense of others. However, I considered that I 

 had already accumulated sufficient data on this point. These animals 

 had now become invaluable for the solution of another and biological 

 problem, namely, whether dog A, if it were now to be given an abundance 

 of food, would increase in weight and size and make good the growth 

 it lost in its youth. It also was necessary to determine whether dog A 

 would finally attain the same weight and size as dog D. 



Therefore, startiiig on the three hundred and fifty-fifth day, the food 

 of number A was augmented to 230, 280, 340, 450, and finally 680 

 calories each day. An increase in body weight was noticed almost at 

 once and the animal continued to gain steadily. At the same time it 

 became rounder, the bones did not show through the skin as they did 

 before, and the sharp angles disappeared. The diet from the four 

 hundred and thirty-first day was the same as that of the control dog 

 B, and following this a further increase in weight was observed. The 

 animal continued to fatten, but apparently it did not increase in length 

 nor in height. In order to determine if this dog still had the capacity 

 for growing, to offset the lack of growth brought about by his restricted 

 diet in youth, the same measurements were taken on the five hundredth 

 as were recorded on the three hundred and fiftieth day, before the food 

 was increased. These values are given in the following table and in- 

 dicate clearly that during this period dog A, while receiving a more 

 than ample diet and gaining in weight from 2,450 to 5,440 grams, 

 practically did not increase in length or height, but only very greatly 

 in circumference. 



