TRANSPLANTATIONS 49 



favorably also on the epithelium and a vicious circle is thus established in the 

 epithelium-stroma relations. Also, the uterine epithelium is not seriously af- 

 fected by the homoiotoxins, if at all ; but secondarily, the epithelium is injured 

 by the lymphocytes. While the lymphocytes appear at about as early a time in 

 or around the homoiogenous uterine tissues as around the corresponding 

 thyroid and kidney tissues, in the latter the lymphocytic reaction becomes much 

 stronger than in the former. The resistance of the epithelial structures in the 

 homoiogenous uterus is indicated also by the fact that mitotic proliferation 

 continues actively in the transplanted uterine epithelium much longer than in 

 thyroid and kidney. 



9. The effect of autogenous and homoiogenous bodyfluids on the devel- 

 opment of placentomata in the transplanted uterus. If the non-transplanted 

 uterus has been sensitized by the corpus luteum hormone about five to eight 

 days after estrus, incisions into the uterine horn or introduction of foreign 

 bodies into the uterus call forth the production of placentomata, which reach 

 their full development in about ten days, while at a still later period regression 

 of these newformations sets in. If instead of making incisions into the uterine 

 mucosa in situ, we autotransplant pieces of the sensitized uterus about six days 

 after estrus, the mechanical stimulation due to the process of transplantation 

 likewise leads to placentoma formation in the transplanted periglandular con- 

 nective tissue, which proliferates actively by means of mitoses. At the height 

 of the development, pearls and also giant nuclei may form in certain areas in 

 the placentoma; the other uterine tissues are well preserved and lymphocytes 

 are absent, but some spindle-cell connective tissue with mitoses may grow into 

 the placentoma and destroy parts of it. 



If pieces of the uterus are homoiotransplanted instead of autotransplanted, 

 the results differ in accordance with the availability of corpus luteum hor- 

 mones in the host ; however, even under the most favorable hormonal condi- 

 tions the homoiotoxins always tend to exert an injurious effect on the trans- 

 plants. If the homoiotransplantation is made into guinea pigs, in which estrus 

 has taken place about six days previous to transplantation, in the large ma- 

 jority of the animals only traces of or very slight placentomata developed, or 

 none. Occasionally, large placentomata developed, but in this case there 

 seemed to be more necrosis in these homoiogenous than in the autogenous 

 structures; also, moderate or even marked lymphocytic infiltration could be 

 found about 10 or 11 days after transplantation in some of the connective 

 tissue of the transplant. 



In five pregnant guinea pigs, pieces of uterus were homoiotransplanted. In 

 two animals no placentomata developed, while in three there were small 

 placentomatous areas. Lymphocytic infiltration in the surrounding tissue was 

 moderate, or, in places, more marked, and it was found also directly in the 

 placentomatous formations ; again, the ingrowth of spindle-cell connective 

 tissue could destroy and replace part of the placentomata. After transplanta- 

 tion of the uterus pieces into male or into sexually immature female guinea 

 pigs, no placentomata developed and the degree of lymphocytic infiltration 

 varied in different cases. 



