48 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



connective tissue in the autotransplant and, in general, there are many mitoses 

 here. In the homoiotransplant the epithelium is flatter, there are more lympho- 

 cytes and the connective tissue has a more fibrillar-cellular character. The 

 unstriated muscle tissue is either lacking or it is invaded by connective tissue 

 in the homoiotransplant. However, certain variations as to the differences be- 

 tween autogenous and homoiogenous transplants occur in individual cases ; 

 but on the whole, the recovery of the autogenous tissue is better and especially 

 the myxoid connective tissue and unstriated muscle are better preserved in 

 the autotransplant and there are here fewer lymphocytes. In the homoiotrans- 

 plant, the epithelial cyst remains incomplete and there is more necrotic tissue, 

 but even in this kind of graft the lymphocytes are not present in large masses 

 and they are not very injurious during the second week and first half of the 

 third week, but they may destroy the uterine glands and injure the surface 

 epithelium. 



In the homoiotransplant the connective tissue still invades the unstriated 

 muscle tissue and gradually during the latter part of the third and the begin- 

 ning of the fourth week the lymphocytes become more frequent around and in 

 the graft, and very little myxoid connective tissue or muscle tissue is, at this 

 time, to be observed. The surface epithelium, some glands, and the peritoneal 

 epithelium are more resistant to the action of the homoiotoxins than are the 

 myxoid connective tissue and the unstriated muscle tissue. On the other hand, 

 the amount of hyaline connective tissue increases, at least partly on account 

 of the progressive organization of the necrotic material. In the middle of the 

 4th week, the latest period at which living homoiotransplanted tissue was 

 seen, few mitoses were found in the epithelium, although this epithelium and 

 the peritoneal endothelium were relatively best preserved, while the myxoid 

 connective tissue and the muscle tissue were replaced by fibrillar and hyaline 

 connective tissue. 



It follows from these experiments that great parts of the homoiotransplanted 

 uterus are primarily damaged by the action of the homoiotoxins, that uterine 

 tissues attract the lymphocytes less strongly than do kidney and thyroid, and 

 that these cells are of less significance in uterus than in thyroid and kidney. In 

 uterus transplants the lymphocytes contribute only secondarily to the destruc- 

 tion of the graft and then chiefly through their action on the epithelial struc- 

 tures. Thyroid and kidney are largely epithelial structures, they are less 

 affected by the body fluids of the homoiogenous host, although a primary effect 

 of the strange bodyfluids may be exerted also on these organs; but, in the 

 main, their destruction is brought about by lymphocytes and connective tissue 

 cells. It is probable that without the injurious action of these cells of the host, 

 the homoiogenous thyroid and kidney would survive longer than the homoiog- 

 enous uterus transplants. The latter tissues cannot recover as well from the 

 primary injury caused by the process of transplantation, nor can their epi- 

 thelium induce or maintain the myxoid-cellular character of the stroma as well 

 as autogenous tissues. Furthermore, the tissues that have recovered cannot 

 maintain themselves permanently in the homoiotransplants because of the in- 

 adequacy of the bodyfluids. The changes produced in the stroma react un- 



