Abstract
Experiments were undertaken to test the effects of heteroplastic grafts in animals as widely separated as mammals and amphibia. Testicular and thyroid tissues from albino rats were placed in the larvae of Rana catesbiana, and other experiments are in progress with both embryonic and adult tissues.
In the first series of grafts no effort was made to control temperature, the experimental animals being left at room temperature of approximately 20, subject to diurnal fluctuations. The tissues to be grafted were removed aseptically, and simply placed within the coelomic cavity of the tadpole, the coils of the intestine keeping the transplant in place against the peritoneum of the body wall. The operative animals were kept in tap water.
Histological preparations of the tissues show that after 2 days the testicular grafts become adherent to the body wall, and embryonic connective tissue cells from the tadpole begin to invade the transplant. Growth is more rapid near a broken surface, i. e., at the point where the graft lies near the incision in the body wall. At 4 days, encapsulation by the host is well under way, with an interlacing of connective tissue fibers between the tunica of the testis and the peritoneum of the host. The germinal epithelium shows some degeneration but mitotic cells are still evident. At this time capillaries from the tadpole enter the transplanted tissue, the vessels following the trabeculae of the invading connective tissue. The blood supply in most cases comes from the body wall, though it may come from the serous coat of the intestine.
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