i9o8.] TRANSPLANTATION OF VESSELS AND ORGANS. 679 



sufficient caliber. After a few months, the transplanted segment 

 assumes exactly the same appearance as the normal vessel. The 

 carotid of a dog was examined three months after the graft of an 

 arterial segment. The transplanted segment was exactly similar to 

 the other parts of the artery. There was no modification of caliber. 

 The elasticity was normal. The only evidence of the operation was 

 two whitish transverse lines on the intima. The remote results are 

 excellent. A dog, into whose aorta a segment of aorta from 

 another dog had been transplanted, was living and in good health 

 nine months after the operation and the femoral pulse was normal. 

 The transplantation of arteries has already been attempted in human 

 surgery by Pierre Delbet in the treatment of aneurism. When a 

 large artery is wounded and partially destroyed, or when a tumor 

 adherent to the main vessels of a limb renders necessary the extir- 

 pation of these vessels, the substitution of a new piece of artery to 

 the removed part would prevent the occurrence of gangrene. 



The graft of an artery of an animal into an animal of different 

 species is often successful if the animals are closely related. I 

 transplanted several times segments of dog's carotid arteries on the 

 abdominal aorta of cats with excellent functional results. Never- 

 theless, these results cannot be compared with those obtained in 

 transplantation between animals of same species. Sometimes the 

 lumen becomes dilated, or even a fusiform aneurism can be found. 

 Even when the functions of the transplanted segment are perfect, 

 its wall undergoes marked histological changes. The elastic frame- 

 work disappears and progressively the muscular fibers are resorbed. 

 After a few months, they have practically disappeared. The ves- 

 sel is then composed mainly of connective tissue. 



Veins can easily be grafted on arteries. I performed several 

 times the transplantation of the vena cava on the aorta, on dogs and 

 on cats, with excellent results. A segment of vein transplanted 

 into an artery undergoes immediately very marked changes. The 

 wall, which is very thin, becomes thicker and stronger. The lumen 

 is often dilated, but no aneurism has ever been observed. On the 

 contrary, the vein reacts against the increased blood pressure by 

 thickening its wall. The thickening is due to an hyperplasy of the 

 muscular cells and an hypertrophy of the adventitia. There is also 



