PHYSIOLOGICAL PROPERTIES OF GONADS 369 



MATERIAL AND TECHNIC 



The technic employed in gonad transplantation has been ade- 

 quately described in the preceding papers of this series. It is 

 sufficient here to state that the normal sex glands were removed 

 from the guinea-pigs (total castration) at an age of ten to twenty 

 days after birth and that portions of the gonad from the oppo- 

 site sex were grafted subcutaneously or intraperitoneally. In 

 some animals two, three, or even four transplantations were made 

 at intervals of five to ten days. 



The fact that transplantation of gonads in guinea-pigs was less 

 successful than in rats was mentioned in an earlier paper; in some 

 of the guinea-pigs as many as four successive grafts have been 

 made on the same animal without any of the grafts persisting. 

 Over fifty guinea-pigs have been used in this series of experiments, 

 but only a few examples will be given to illustrate the results. 



BEHAVIOR OF CASTRATED MALES AND SPAYED FEMALES 



The most obvious result of castration of the male in the major- 

 ity of animals is the total loss of all sex inclinations, if not at once, 

 at least within a short period of time. However, exceptions to 

 this general rule have been encountered many times in male 

 guinea-pigs. Castration was performed by opening the peritoneal 

 cavity, retracting the testicle into the abdominal cavity, tying off 

 the spermatic cord with surgical silk thread to prevent bleeding 

 from the internal spermatic artery, and cutting the cord consid- 

 erably above the testicle, removing this organ entire. It is abso- 

 lutely certain that in all cases the entire testicle was removed. 



The castrated male animal, however, in many cases after a 

 period of four to six months continues to exhibit the psychical 

 characteristics of the normal male in that it utters the male sex 

 call when a strange animal is placed in its cage, and many times 

 will follow the female and even attempt to fulfill the normal func- 

 tions of the male. This has been observed in many cases, but 

 with these different individuals, as indeed with normal males, some 

 are more vigorous in their reactions than are others; at times the 

 reactions are so vigorous that one not acquainted with the condi- 

 tion of the animal would unhesitatingly take it for a normal male 

 animal. 



