66 HAYATO ARAI 



It is interesting to note (table 4) that before puberty tne sur- 

 viving ovary is about 40 per cent heavier than that of the con- 

 trols, while after the appearance of corpora lutea it becomes 

 more than 100 per cent heavier. 



As has been stated, Bond ('06) found in semispayed adult 

 rabbits the compensatory hypertrophy of the surviving ovary. 

 The hypertrophied ovary had twice the weight of the ovary 

 previously removed. This growth he attributes to the increase 

 in the ovarian stroma. Thus Bond compared the weight of the 

 surviving ovary with the weight of the ovary of the same animal 

 at the time of its removal. Bond simply stated, from counting 

 the new large corpora lutea, that there are approximately the 

 same number of these in the surviving and in the removed ovaries. 

 However, since a new formation of corpora lutea usually occurs 

 in association with sexual activity, there must remain a greater 

 number of old corpora lutea in the surviving mature ovary, even 

 granting that some of these were either degenerated or otherwise 

 changed. 



If such were the case, the presence of more corpora lutea in 

 the surviving ovary would make it heavier and larger and so 

 produce the compensatory hypertrophy. 



Carmichael and Marshall ('08) semispayed three non-pregnant 

 rabbits and found a definite compensatory hypertrophy in the 

 surviving ovary after two, four, and five months; and in one 

 rabbit in which pregnancy occurred subsequent to the removal 

 of the ovary, the surviving ovary, when examined four and a 

 half months later, weighed twice as much as the ovary previously 

 removed. These authors concluded that sexual intercourse is 

 not necessary to induce a compensatory hypertrophy in the 

 ovary. 



My own observations lead to the same conclusion as that 

 reached by Carmichael and Marshall. In tables 3 and 4 are 

 shown the two litters in series II, which were separated absolutely 

 from the males, and in which after puberty the weight of the 

 surviving ovary is twice or more than twice that of the corre- 

 sponding ovary of the control at hke age. 



