SYNGENESIOTRANSPLANTATION 79 



from the same donor into the same host, behave in the same manner and have 

 a corresponding fate. There are hosts in which all pieces are well preserved, 

 others in which all transplants are destroyed, and still others in which the 

 transplants show an intermediate degree of preservation. 



The behavior of lymphocytes towards different types of transplants. We 

 have discussed non-specific factors which influence the fate of transplants, 

 without any participation of lymphocytes or connective tissue cells being 

 necessary in this process ; we have also discussed non-specific reactions on the 

 part of connective tissue towards the transplants. Likewise, in the case of the 

 lymphocytes, factors other than the individuality differentials may be present 

 in or around the transplant, and may influence the activity of these cells 

 towards the graft. Thus foreign bodies around or in a transplant may cause 

 an accumulation of lymphocytes, as may also epidermal cysts, in some in- 

 stances even if the latter are autogenous in nature. Mildly inflammatory altera- 

 tions of a chemical nature, or more severe ones acting at a distance from the 

 exciting agent, may attract lymphocytes. But it seems that necrotic material 

 does not exert a direct attraction on these cells ; they do not usually invade 

 necrotic material unless it is invaded first and organized by growing connective 

 tissue; in the latter, some collections of lymphocytes are often found. But the 

 most characteristic feature of the lymphocytes is that they are attracted by 

 strange individuality differentials. The degree of this lymphocytic reaction 

 shows a curve which has its maximum at a point intermediate between the 

 autogenous and the severe homoiogenous zone of the relationship spectrum ; 

 the lymphocytic infiltration is frequently less marked in the latter zone, because 

 here the greater part of the transplant has become either necrotic or is replaced 

 by host tissue. The maximum of the curve may be in the syngenesious zone or 

 in the zone of mild homoiogenous reactions. In the different types of trans- 

 plantations lymphocytes move usually by way of the lymph vessels, but to a 

 lesser degree, also by way of the blood vessels, in the direction towards and 

 into the center of the transplant. To a certain extent they tend to accumulate in 

 different places in different kinds of transplanted tissues. It is of special inter- 

 est that they seem to prefer certain tissues to others. In the thyroid they may 

 first collect along the inner border of the ring of preserved acinar tissue. In 

 cartilage-fat transplants they accumulate in the fat tissue, where there is a 

 deposit of fibrous tissue containing vessels; but they also collect around the 

 perichondrium and cartilage and they may invade that portion of the cartilage 

 which consists almost entirely of cartilage cells. In the skin they often avoid 

 the sebaceous glands and the epithelium of the hair follicles when this is pre- 

 served. Of special interest is their behavior in the ovary ; here they infiltrate 

 first the fat and connective tissue surrounding the ovary ; they then accumu- 

 late in the interstitial gland, around the germinal epithelial cyst and in the 

 central connective tissue underneath this cyst, as well as around the medullary 

 ducts, and they may invade also corpora lutea. However, they avoid the pre- 

 served follicles and only quite late and rather rarely do they invade the latter. 

 In this case, the difference between their behavior towards different con- 

 stituents of the same organ is almost as great as the difference in their reaction 



