STUDIES ON BARTONELLA MURIS ANEMIA VI. A LIPOlD EXTRACT OF THE SPLEEN THAT PREVENTS BARTONELLA MURIS ANEMIA IN SPLENECTOMIZED ALBINO RATS

In previous work (1), the authors have demonstrated that minute splenic autoplastic transplants made 7 weeks prior to splenectomy protect a large percentage of splenectomized rats against Bartonella muris anemia. A comparative histological study of the transplants of protected and unprotected rats revealed a regeneration of the pulp cells in the protected rats, and an exhaustion destruction of the pulp in the unprotected rats. This supported the hypothesis that the reticu-lar and endothelial cells of the pulp of the spleen elaborate some internal secretory substance having an influence to prevent Bctrtonellc~ infection. Lauda and Flaum (2) found that rats joined by parabiosis are protected against Bartonella muris anemia if the spleen of only one animal is removed. From their experiments these investigators concluded that the protective action is due to a hormonal substance produced in the spleen. Unsuccessful attempts have been made by numerous investigators to demonstrate some substance in the spleen which would replace this organ in protecting adult splenectomized rats against Bartonellc~ muris anemia. During the past 3 years we have made many attempts to obtain such an extract. Feeding raw or cooked spleen of ox, calf, pig, or rat had no effect on the course of the disease. Recently, however , lipoid extracts of the spleen have been prepared which possess the property of protecting splenectomized adult albino rats against Bartonella muris anemia in a large percentage of instances. Since the anemia is more severe in the male, only male rats were used in testing the extracts. In no instance among 440 male rats of carrier stock used for studies of Bartonellct muris anemia during the 777