THE RELATION OF THE SPLEEN TO BLOOD DESTRUCTION AND REGENERATION AND TO HEMOLYTIC JAUNDICE : V. CHANGES IN THE ENDOTHELIAL CELLS OF THE LYMPH NODES AND LIVER IN SPLENECTOMIZED ANIMALS RECEIVING HEMOLYTIC SERUM.

In a large proportion of dogs that have been splenectomized for periods of two weeks or more, one finds a great increase in the number of endothelial cells of the lymph nodes. In most splenectomized dogs that succumb to an injection of hemolytic immune serum within forty-eight hours, the sinuses of the lymph nodes contain large numbers of endothelial cells, phagocytic for red cells. This is not seen in normal dogs receiving hemolytic serum. Likewise a similar power of phagocytosis is seen frequently in the stellate cells of the capillaries of the liver. Both in the lymph nodes and the liver these cells appear to be formed in situ; we find no evidence that they have been transported to these organs. Such findings suggest the development of a compensatory function on the part of the lymph nodes and possibly of the liver. Normally the spleen contains cells which have the power to engulf and presumably to destroy the red blood corpuscles. In certain pathological conditions this function is frequently greatly augmented and may sometimes be shared by the lymph nodes, for example, in typhoid fever, as was first clearly shown by Mallory. Our observations suggest that in the absence of the spleen, this function of forming red blood corpuscle-phagocyting cells, normally a minor activity of the lymph nodes, becomes highly developed in the latter organs, and that these cells, and the stellate cells of the liver, thus assume, in part at least, the function of destroying red blood corpuscles by phagocytosis. In view of the somewhat limited material at our disposal, we offer this, not as definitely conclusive, but as evidence which, in connection with the work of others, is highly suggestive of the possibility of the lymph nodes assuming some of the function of the spleen. Whether this activity of the endothelial cells of the lymph nodes and the liver has any bearing on the anemia that follows splenectomy and on the occurrence of spontaneous jaundice in the late periods after splenectomy, is not yet clear.