200 HEMOLYSIS AND SERUM CYTOTOXINS 



HEMOLYSIS IN DISEASE 



During health there is always going on a certain amount of 

 destruction of red corpuscles that have outlived their usefulness ; 

 hence in disease we may have to deal with either an alteration 

 in the normal processes of blood destruction or the introduction 

 of entirely new processes. Although the place and manner of 

 normal red corpuscle destruction is not completely known, yet 

 it seems probable that there is relatively little hemolysis within 

 the circulating blood. When a red corpuscle becomes damaged, 

 it seems to become more susceptible to phagocytosis, and it is 

 then picked out of the blood, chiefly by the endothelial cells of 

 the sinuses of the spleen, hemolymph glands, and bone-marrow. 

 Within these cells it apparently undergoes hemolysis. Eventu- 

 ally, the resulting pigment is split up by the liver, the nou- 

 ferruginous portion forming the bile-pigments, while the iron 

 seems to be mostly withheld to be worked over into new hemo- 

 globin. (See " Pigmentation, " Chap, xvi.) Whenever during 

 disease red corpuscles are more rapidly injured than they are 

 under normal conditions, these processes of normal hemolysis 

 are exaggerated and we not only find the phagocytic cells of the 

 spleen and glands packed with corpuscles, but endothelial cells 

 elsewhere, and also leucocytes, take on the hemolytic function. 

 At the same time there results an excessive production of bile- 

 pigment from the destroyed red corpuscles, which has an etio- 

 logical relation to the so-called " hemato-hepatogenous " jaun- 

 dice. If hemolysis is very excessive, the blood pigment 

 accumulates in other organs than the liver and spleen. When 

 at one time over one-sixtieth part of the hemoglobin of the 

 blood is in solution in the plasma, it may escape in the urine, 

 producing hemoglobinuria. 



The hemolysis of the acute febrile diseases is readily explained 

 by the demonstrable hemolytic property of the products of the 

 organisms that cause them, such as streptocolysin, staphylolysin, 

 etc. Perhaps at the same time products of altered metabolism 

 may also play a part, but it does not seem probable from experi- 

 mental results that the thermic condition per se has much effect. 

 In malaria, although the parasites enter and destroy the cor- 

 puscles in which they live, yet this alone does not account for 

 all the blood destruction of the disease, for the amount of 

 anemia is quite without relation to the number of parasites to 

 be found. There is good reason to believe that the plasmodia 

 produce hemolytic substances that are discharged into the 

 serum. 1 In the primary anemias hemolysis seems to be the 

 1 Regnault, Rev. d. Med., 1903 (23), 729. 



