250 O. ISHII. 



months later, at the age of 4 to 5 months, it attained its full 

 weight, about 20 to 28 ounces, but one exceptional animal 

 weighed 34 ounces in a non-pregnant condition. However, if 

 we feed a special diet of nutrient material and the animal is 

 otherwise well taken care of, then the growth progresses rapidly 

 and the heat begins earlier than usual. The guinea pig which 

 weighed 34 ounces was fed on the usual farm or laboratory food. 

 Therefore we must remember that the growth of the young 

 depends considerably upon the character of the food. 



