ULTIMATE RESULTS OF AORTIC TRANSPLANTATIONS.

In the first experiment, a segment of popliteal artery, extirpated from the leg of a young man and preserved for twenty-four days in cold storage, was transplanted upon the abdominal aorta of a small bitch. The animal lived in excellent health for four years and two months, became pregnant several times, and finally died during labor. The abdominal aorta was normal, but the human arterial segment was slightly dilated, and its wall was composed of connective tissue only. In the second experiment, a segment of dog's jugular vein, preserved for twenty-four hours in cold storage, was transplanted upon the thoracic aorta of a fox terrier. In spite of slight lesions of the cord due to interruption of the aortic circulation during the operation, the animal remained in excellent health. After two years and two months, the dog died of an epidemic disease. The descending aorta was normal. The transplanted segment had about the same caliber as that of the aorta, but its wall was composed of connective tissue, with no evidence of muscular or elastic tissues. In these two experiments, the walls of the transplanted segments contained neither muscle nor elastic tissue fibers and were not thicker than those of the artery. Nevertheless, they were able to withstand the pressure of the blood without undergoing any marked dilatation. If death due to accident had not brought these two experiments to an end, it is probable that the transplanted segment would have successfully resisted the pressure of the blood for a much longer time. As it is, the result shows that, in one experiment after four years and in the other after two years, the segments transplanted upon the abdominal and thoracic aortas were still efficient.