668 FKANK C. MANN 



increased wouk thrown on the remaining similar structures by the removal 

 of the largest mass of lymphoid tissue in the body, with a resulting hyper- 

 plasia arid increased activity. 



The Spleen and the Blood. The function of the spleen in relation 

 to the physiology and pathology of the blood is more closely and more 

 clearly defined than that of any of its other alleged functions. For 

 instance, it is definitely known that in fetal and early life, erythrocytes 

 are produced in the spleen. The evidence is also quite strong that the 

 spleen destroys erythrocytes, presumably the old and wornout cells, 

 although experiments dealing with variation in blood counts in the splenic 

 artery and vein are not- in accord. A rather extensive review of the 

 literature on this question has been made by Morris (a) (&), Pearce, 

 Krumbhaar and Frazier. 



Splenectomy produces more marked and constant changes in the blood 

 than in any other tissue. These changes have been studied in a large 

 number of researches and in a wide range of species. A few of these 

 studies are by Luciani, Musser and Krumbhaar, Pearce, Austin and 

 Musser, Freytag, Kreuter, Wolferth, Orr and Henri. They involve a 

 study of the blood following splenectomy in normal men (Meyers) and of 

 those from which the spleen had been removed for a pathologic condition 

 (Giffin, Eppinger). 



The most constant changes in the blood produced by removal of the 

 spleen are a varying degree of anemia, increased resistance of the erythro- 

 cytes, lessened tendency to jaundice following the administration of 

 hemolytic agents, and an increase in the leukocytes. The anemia follow- 

 ing splenectomy usually is not marked nor of long duration, reaches 

 its point of greatest severity between the first and second months and 

 returns to normal within three or four months. The hemoglobin curve 

 follows quite closely that of the red cell count. During the process of 

 regeneration, an abnormal type of red blood cell appears in the circulating 

 blood, and nuclear particles have been described (Morris, Koth, Gilbert). 

 It is interesting to note that diet affects the changes in the blood (Pearce, 

 Austin and Pepper). 



One of the most constant findings following splenectomy is increased 

 resistance of the erythrocytes to hypotonic salt solution and to hemolytic 

 poison. Almost all of the large number of investigators are agreed on 

 this finding; however, the explanation for it has not been given. The 

 literature is reviewed by Pearce, Krumbhaar and Frazier. The lessened 

 tendency to jaundice following administration of hemolytic agents is a 

 quite constant phenomenon and still not explained. 



The results from the effect of splenectomy on the leukocytes are not 

 in accord. Recently the literature on the subject has been reviewed by 

 Orr. Most investigators have noted a definite leukocytosis, relatively high 

 the first twenty-four hours after removal of the spleen, and then gradually 



