156 P. L. Krohn 



who have developed an ingenious marker gene technique for 

 distinguishing between the offspring from the grafted ovary 

 and from any ovarian tissue that regenerates, have shown 

 that htters can be obtained even from embryonic ovaries 

 that have been transplanted into young adult animals. 



Russell and Douglass (1945) have also used the method to 

 study what happens to the ovaries when they are submitted 

 to abnormal hormonal influences during a temporary stay in 

 the spleen of castrated hosts before being returned to a normal 

 endocrine environment. They find that the oocyte producing 

 apparatus is unable to withstand such treatment, although 

 the endocrine function is unaffected. 



My own experiments using transplantation methods have 

 been directed along the following lines. 



Problem of technique 



The only serious difficulties raised by the technique of 

 intra-capsular grafting are incomplete removal of the ovary 

 and bleeding from the cut ovarian vessels. Even the most 

 meticulous surgery cannot always obviate the first difficulty, 

 but the effects can be mitigated by using the gene marker 

 methods introduced by the Bar Harbor workers. Patience 

 seems to be the only way of overcoming the second. The 

 use of a diathermy-cautery was unsatisfactory because it 

 damaged the delicate tissues of the fallopian tubes. 



The mere fact of transplantation is sufficient, according to 

 Hummel, Fekete and Little (1953) to increase the proportion 

 of ovarian tumours that develop in later life. The results of 

 any work which uses the method may, therefore, have to be 

 interpreted with some caution. 



The survival of ovarian homografts 



In view of the widespread differences of opinion about the 

 chances of survival of ovarian homografts, discussed elsewhere 

 (Krohn, 1955), I have carried out a further series of experi- 

 ments in which ovaries from one strain of mouse have been 

 transplanted orthotopically into the ovarian capsule of mice 



