Simultaneous autologous and homologous musculofascial transplants were made in New Zealand white rabbits. The basic pattern of degeneration and granulation tissue organization of both types of transplant was essentially identical. The superposition of two reactions in the framework of organizing granulation tissue served to distinguish homologous from autologous transplants. One reaction to homologous transplants was predominantly characterized by lymphocytic infiltration and the other by angeitis. The principal locus of these reactions was in the musculofascial zone of the transplant, and from this zone the reactions spread to a variable degree through the fascia into the overlying pannus of granulation tissue. When single homologous transplants were made, the lymphocytic and mild angeitic forms of reaction predominated, becoming conspicuous at the end of 2 weeks. When multiple successive homologous transplants were made from the same donor to the same recipient, acute angeitis with thrombosis supervened and the lymphocytic reaction failed to develop or persist. Multiple successive autologous transplants, on the other hand, did not influence the type or degree of reaction to autologous transplants in the same animal. There was no evidence that autologous transplants had any influence upon the sequence of reactions to homologous transplants or that the presence of homologous transplants influenced the nature of the reaction to autologous transplants in the same animal.
Until better methods are developed, methods of bio-assay of the type described, though lacking in quantitative precision, offer the best means for further analysis of factors which govern the incompatibility of tissues of one animal for those of another animal of the same species.