GONADS AS CONTROLLERS OF CHARACTERISTICS 151 



ternal behavior. Steinach has described at great length the 

 docility of the normal female rat (does not fight, is easily handled, 

 not so apt to bite or to resist handling, etc.), but here again the 

 variations are too great to be of any practical value. Many 

 females of this colony used are decidely more pugnacious than 

 males. In several cases, these, after repeated handling would 

 bite, scratch, and resemble any other than a meek and mild- 

 tempered female, and at the same time the males show entirely 

 as mild and even-tempered disposition as any female of the 

 colony. 



As for the sex reactions, it is true that, in cattle especially and 

 in some other animals, the females often attempt to imitate the 

 role of a male; but among rats this tendency has, so far as known, 

 never been observed. As noted above, female rats have been 

 placed in cages with normal females, early spayed females, and 

 old females (each of these having been in isolated cages for 

 some days), but in no case have they attempted to imitate the 

 male. Aside from the general reactions exhibited by any two 

 strange rats when placed together, the reactions except in cases 

 of transplanted testis, have been negative. 



MICROSCOPICAL OBSERVATIONS 



The litter from which most of the data for this paper has been 

 taken afforded excellent material for these considerations on 

 account of the fact, mentioned previously, that one or more of 

 the transplanted gonads were retained for the 225 days between 

 the time of operation and the termination of the experiment. i'* 

 The animals were killed wdth ether and the transplanted glands 

 removed from the place of growth and development; the tissue 

 was killed in Bouin's fluid, sectioned, and stained with haema- 

 toxjdin and eosin. 



The young ovary successfully transplanted into a young male 

 animal persists and undergoes its differentiation in quite a nor- 



" The blood circulation in these transplanted pieces of tissue was estab- 

 lished in different cases, either principally through blood connection with vessels 

 of the muscles or from cutaneous vessels in the superficial fascia. 



