Autografts of the Spleen in Rabbits. 123 

 73 (1251) 



Influence of age on the permanence of subcutaneous autografts 

 of the spleen in rabbits. 



By David Marine and O. T. Manley. 



[From the H. K. Cushing Laboratory of Experimental Medicine, 

 Western Reserve University, Cleveland, Ohio.] 



We have removed the spleen and auto transplanted in 49 

 rabbits, varying in age from 26 days to over two years. 



The method consists of introducing a small fragment of 

 spleen, roughly 2-3 mm. in diameter, beneath the subcutaneous 

 fascia of the abdomen, through a skin incision which is then 

 closed by suture. These transplants have been subjected to 

 direct examination at approximately monthly intervals to check 

 their taking, growth or absorption. All have taken, except for 

 three instances and these failures were due to infection. The 

 most striking observation was the rapid growth of the grafts in 

 the young rabbits from one to three months old and the lack of 

 growth in the one- and two-year-old rabbits, some of which have 

 undergone complete absorption in three months, as shown by 

 histological examination. On the other hand, none of the trans- 

 plants in rabbits less than five months old have shown any tend- 

 ency to undergo absorption and histological examination shows 

 regeneration of the major splenic elements into normal looking, 

 encapsulated, highly vascular little spleens. 



We have not been able to complete the series, with rabbits of 

 known ages, between the period of sexual maturity (fifth month) 

 and one year. The marked growth and activity of the trans- 

 plants in young rabbits as compared with the lack of growth 

 and tendency to absorption in old rabbits may be a part of the 

 normal growth of the animal. In favor of this view is the fact 

 that further growth of the transplants has not been observed after 

 adolescence. There are no reports of differences in the systemic 

 effects of splenectomy relative to age, although there is some 

 evidence from histological studies that a blood-forming function 

 is present in early life and absent in adults. It is suggested that 

 the age differences noted in the growth and activity of spleen auto- 



