CAUSE OF HYPERTROPHY OF SURVIVING OVARY 



63 



TABLE 1 



Killed at 3rd week 



5th week 



6th week 



7th week after operation 



days 



41 

 55 

 62 

 69 



SERIES I. WITH MALES 



Semi- 

 spayed 



Control 



SERIES II. WITHOUT 

 MALES 



Semi- 

 spayed 



Control 



OBSERVATIONS 



As is shown in table 2, there are individual variations in body 

 weight as well as in body length within each Utter, though all 

 the members were kept in one cage and thus raised under identical 

 conditions. Moreover, the growth rate of the litters is not the 

 same, although each litter had nearly the same body weight at 

 the age of twenty days. The real influence of semispaying on 

 the growth of the body in weight and in length, as well as on 

 the weight of ovaries, is best seen in table 3, in which all the 

 characters are given their average values. 



Examination of table 3 shows a better growth in both the body 

 weight and the body length in the operated rats in five out of 

 eight litters. However, the difference is slight, as can be seen in 

 table 4, and I do not think it significant. In table 4 we find 

 the average ratio in body weight is 1.06 in series I and 0.98, in 

 series II. 



I therefore conclude that so far as the body weight is concerned, 

 semispaying has no influence on the growth. 



Similarly, we find the average ratio for body length 1.00 in 

 series I and 0.98 in series II — a result which leads to a like 

 conclusion. 



Thus, my own observations agree with those of Stotsenburg 

 ('13), who also studied the effect of semispaying on the body 

 growth of the albino rat, and who concluded that the absence 

 of one ovary does not modify the general body growth of the 

 operated animal. 



