Chapter 10 



Heterogenous Transplantation of Normal 

 Tissues and of Blood Clots 



We shall now discuss the characteristic features of heterotrans- 

 plantation. The marked toxicity of the bodyfluids, causes early 

 injury and necrosis of the transplants, without the co-operation 

 necessarily of cellular elements of the host. This necrosis affects different 

 organs and different tissues with unequal rapidity in accordance with the 

 degree of resistance of these structures, and even within the same organ or 

 tissue there may be differences in the rapidity of necrosis, inasmuch as those 

 parts which are in general more resistant in their constitution, or which, 

 owing to their situation, are more protected against various kinds of injurious 

 factors, succumb less quickly to the action of the heterotoxins. Organs or 

 tissues which have a low degree of resistance, such as bone marrow, or a 

 medium degree of resistance, such as thyroid, kidney, fat tissue, striated 

 muscle tissue or epidermis, are destroyed by the heterotoxins within one or 

 two weeks. In the skin, the hair follicles are more resistant than the epidermis 

 proper, a fact which agrees with the observation that under certain conditions, 

 for instance, after painting the skin with the carcinogenic hydrocarbon 

 methylcholanthrene, the epithelium of the hair follicles shows a higher degree 

 of resistance than other parts of the epidermis. Cartilage may survive for 

 four weeks or somewhat longer, although in some instances it may undergo 

 necrosis sooner. Thus, in transplantation from rat to guinea pig, necrosis of 

 cartilage and perichondrium may be found after 20 days or even as early 

 as after 12 days. Likewise, in the exchange of tissues between rat and mouse 

 the greater part of the cartilage in one case was preserved as late as 25 days 

 after transplantation, while in some other animals cartilage and perichondrium 

 soon became entirely necrotic. Fat tissue as a rule was found necrotic very 

 early, as for instance, after 6 days, and it was usually invaded by connective 

 tissue cells and by small vacuolated cells, the latter evidently representing 

 phagocytes, which took up fat in the form of small droplets. Some lymphocytes 

 were observed admixed to the connective tissue and polymorphonuclear 

 leucocytes were found frequently, sometimes in large quantities, sometimes 

 only as scattered cells. There were certain heterotransplants in which no 

 leucocytes were to be seen at the time of examination. After homoiogenous 

 transplantation the necrosis of the fat tissue is, as a rule, less extensive than 

 after heterotransplantation, the necrotic tissue is less actively invaded by 

 connective tissue, and furthermore, under sterile conditions of operation 

 the polymorphonuclear leucocytes are usually entirely lacking, except in the 

 first few days after operation. 



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