76 HAYATO ARAI 



Why, then, does the complete removal of the ovaries modify 

 the growth rate of the rat while semispaj^ing has no such influence? 



My own study shows that in the surviving ovary of the semi- 

 spayed, as contrasted with that from the controls, a larger num- 

 ber of more or less matm'e follicles, as well as a larger number 

 of degenerated folhcles, are to be found both before and after 

 puberty, while these two ovaries appear similar in other respects. 

 If, therefore, the semispayed is able to maintain the normal 

 body growth, while the complete spajdng modifies it, we come 

 naturally to the conclusion that the preponderance of the mature 

 follicles and of large degenerated follicles must be in some way 

 responsible, and this agrees with Biedl's findings touching the 

 Graafian folhcles. 



It is interesting to note that the rate of growth in body weight 

 tends to be higher in the female than in the male before puberty, 

 after which it is reversed (Donaldson, '15), and thus the appear- 

 ance of the female characteristics coincide with the appearance 

 of the mature follicles in the ovary (Aral, '20). This seems to 

 be a further reason for considering the mature follicles as impor- 

 tant in the modification of body growth. 



The action of the ovarian extracts 



. Itagaki, quoted by Schiifer, stated that the extract of folli- 

 cular tissue or liquor folliculi increases both the normal tonus 

 and the rhythmic movements of the plain muscles and of the 

 uterine strip. 



I have attempted to see whether or not any difference exists 

 between the normal and the semispayed in the action of their 

 ovarian extracts on movements of the intestine. It is, however, 

 impossible to make separate extracts of follicles and stroma cells 

 from the ovaries of albino rats, owing to the minuteness of the 

 organ. Therefore, we prepared extracts from the entire ovaries 

 of the semispayed and of the controls. The technique used 

 was as follows: The fresh ovaries were ground with Tyrode's 

 solution; the amount of solution being always fifty times the 

 weight of the ovaries. After standing from one and a half to 



