KATHARINE M. HOWELL 1043 



Investigators have obtained diverse results in immunity curves after thyroidectomy. 

 Fassin reported a decrease in hemolysin and bacteriolysin; Marbe, a decrease of op- 

 sonin and phagocytic power; Frouin, an increase in tetanus antitoxin; Lerda and Diez, 

 more resistance to intoxications, bacterial and drug; and Fjeldstad, practically no 

 change in antibody formation. 



Splenectomy before or soon after the injection of antigen is the only organ ex- 

 tirpation that appears rather uniformly to give a reduced antibody response. 



THE ROLE or THE RETICULO-ENDOTHELIAL SYSTEM 



Many investigators believe that no one organ can be responsible for so important 

 a function as antibody production, and they consider that many or all the cells in the 

 body may contribute to immunity response. This group of experimenters in the 

 search for antibody formation has considered tissues of widespread distribution, such 

 as the lymphatic tissue, the hematopoietic tissues, or the reticulo-endothelial system 

 of cells. The reticulo-endothelial system of cells has become of increasing interest in 

 the study of immunity response, and a voluminous literature has arisen which has 

 been comprehensively reviewed by Sacks' and by Kritschewski and Meersohn.^ Ac- 

 cording to Aschoff,^ this system of cells has been grouped together because of the com- 

 mon phagocytic properties, and comprises the reticular and endothelial cells of the 

 spleen, the reticulo-endothelial cells of the bone marrow and lymph nodes, the Kupffer 

 cells of the liver, the histiocytes of the general connective tissue, and the monocytes of 

 the circulating blood. Before the cells of the reticulo-endothelial system were defi- 

 nitely grouped together, their ability to phagocytize the red blood cells, bacteria, and 

 other foreign particles had been noted. Cary* had demonstrated that foreign erythro- 

 cytes introduced into the circulation of a rabbit were removed by the fixed tissue cells 

 of the liver and spleen and that extracts of spleen and liver from such an animal had 

 a higher hemolytic titre than the corresponding serum. Kyes^ also concluded that the 

 fixed tissue phagocytes were active producers of antibody, because pneumococci in- 

 troduced into the blood of chickens were quickly taken up by the fixed tissue phago- 

 cytes, particularly those of the spleen. Motohashi^ also found that foreign erythro- 

 cytes were taken up by the cells of the spleen, liver, and bone marrow and that after 

 splenectomy the remaining cells of the reticulo-endothelium were more active. Biel- 

 ing and Isaacs, ^ splenectomizing mice, noticed little effect on antibody (hemolysin), 

 but after splenectomy and blockade of the reticulo-endothelial system with colloidal 

 iron, hemolysins were inhibited. Siegmund* also found hemolysins and hemaggluti- 

 nins reduced or totally suppressed in highly blocked and splenectomized rabbits. Neu- 

 feld and Meyer' found that after blocking and splenectomizing mice they could not 



' Sacks, B.: Physiol. Rev., 6, 504. 1926. 



2 Kritschewski, I. L., and Meersohn, I. S.: Ztschr. f. Immnnitatsjorsch. u. exper. Therap., 47, 

 407. 1926. 



3 Aschoff, L.: Lecture on "Pathology." New York, 1924. 



4 Gary, W. E.: loc. cit, s Kyes, P.: Joe. cit. ' Motohashi, S.: loc. cit. 

 ' Bieling, R., and Isaacs, G.: Ztschr. f. d. ges. e.xper. Med., 28, iSo. 1922. 



^ Siegmund, H.: Klin. Wchnschr., i, 2566. 1922. 



9 Neufeld, F., and Meyer, H.: Ztschr. f. Hyg-, 103, 595. 1925. 



