AUTHOR S ABSTRACT OP THIS PAPER ISSUED 

 BT THE BIBLIOGRAPHIC SERVICE, JULY 26 



ON THE CAUSE OF THE HYPERTROPHY OF THE 

 SURVIVING OVARY AFTER SEMISPAYING (ALBINO 

 RAT) AND ON THE NUMBER OF OVA IN IT 



HAYATO ARAI 

 The Wistar Institute of Anatomy and Biology 



INTRODUCTION 



Bond ('06) has shown that in the rabbit a compensatory hyper- 

 trophy of one ovary may occur when the other has been removed. 

 He states that this process takes place only if the operated animal 

 is permitted to become pregnant or at least to have sexual inter- 

 course. Moreover, he believes this compensatory hypertrophy 

 of the surviving ovary to be caused by the overgrowth of stroma 

 tissue. Carmichael and Marshall ('08) also noted in adult rab- 

 bits the compensatory hypertrophy of the surviving ovary at 

 two to five months after semispaying, but contrary to Bond, 

 hold that this process is independent of pregnancy or sexual 

 intercourse. Furthermore, they found by removing portions 

 of the surviving ovary that the power of compensatory growth 

 is relatively greater the larger the amount of ovarian tissue 

 removed. Doncaster and Marshall ('10) also reported hyper- 

 trophy of the surviving ovary in rabbits. 



Hatai ('13) found that in albino rats after semispaying the 

 compensatory growth of the surviving ovary is almost perfect, 

 and the surviving ovary has therefore nearly twice its normal 

 weight. Hatai operated on rats between sixteen and twenty-two 

 days old and killed them at 326 days. In these same rats Stotsen- 

 burg ('13) followed the growth of the body up to 275 days and 

 concluded that semispaying does not modify either the body 

 weight or the body length, though total spaying produces a 

 definite increase in weight, in a measure due to an accumulation 

 of fat. 



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THE AMERICAN JOURNAL OF ANATOMY, VOL. 28, NO. 1 



