564 



SAMUEL H. HUKWITZ 



study of the influence of splenic extract upon blood formation. Danilew- 

 sky and Krumbhaar and Musser found a surprising increase in hemoglobin 

 and red blood-corpuscles in the peripheral circulation after a single sub- 

 cutaneous or intraperitoneal injection of extract of spleen. In view of the 

 tendency to anemia following splenectomy, this work would suggest that 

 the spleen may exert a stimulating effect upon the formation of red blood- 

 cells in the marrow, were it not for the fact that the evidence for such a 

 conclusion is contradictory and incomplete. Thus, Downs and Eddy 

 very recently found that the subcutaneous injection of protein-free splenic 

 extract is followed immediately by a decrease in the number of erythro- 

 cytes in the circulating blood, which they attribute to a direct hemolytic 

 action of the splenic agent. And Krumbhaar and Musser could not estab- 

 lish that the feeding of fresh spleen to splenectomized animals influenced 



Fig. 2. Composite curve of the hemoglobin estimation of seven dogs after splenec- 

 tomy. (After Pearce, Krumbhaar, and Frazier, "The Spleen and Anemia," J. B. Lippin- 

 cott Company, 1918.) 



in any way the anemia which usually follows splenectomy; nor do the 

 careful histological studies of the bone-marrow made by Pearce and 

 Pepper support this view. While the bone-marrow was not markedly 

 changed during the first two or three months after splenectomy, there was 

 ultimately an increase in the red marrow at a time when the anemia had 

 improved. This late transformation of a fatty into a red marrow they 

 regard not as compensatory to the early anemia caused by splenectomy 

 but rather as a taking over by the bone-marrow, in the absence of the 

 spleen, of the function of storing and elaborating the iron of the old 

 blood-pigment. 



Although there is some support for the theory that the spleen may play 

 a part in blood formation, the tendency in recent literature has been 

 rather to emphasize its function in the destruction of red blood-cells. The 

 experimental and clinical evidence for such a conception of splenic func- 

 tion is attractive but not conclusive. Its main experimental basis is the 

 observation that splenectomy in animals results in an increased resistance 

 of the erythrocytes to various lytic agents and to the mechanical effects of 

 shaking, and that such hemolytic agents as hemolytic serum, saponin, 



