THE MALARIAL FEVERS 



for the arrectores pilorum are also affected, producing goose-skin, 

 Laverania malarice, however, because it sporulates internally, and 

 not in the peripheral blood, causes chills more rarely than the other 

 two. 



De Blasi has shown that an antihaemolysin is formed in the human 

 body, and Casagrandi, as already mentioned, has performed experi- 

 ments on Halteridium in birds, tending to show that this substance 

 has a restraining power against increase of the parasites. 



The only other remarks we can offer on the chemical pathology are 

 limited to the nature ot the pigments, haemozoir and hsemosiderin. 



HiEMOZOiN. — Hsemozoin is the black pigment formed from haemo- 

 globin by the malarial parasites while living in the erythrocytes, 

 and is afterwards distributed over the body on the disruption of 

 the red cells. It is taken up by phagocytes, as already described, 

 and removed from the bloodvessels to the connective tissue, in which 

 it can be^ seen in the liver and spleen. It is soluble in alkalis, 

 but not in water, alcohol, chloroform, ether, or acids. It contains 

 iron, but in the form of an organic compound, which will not give 

 the Berlin-blue reaction. Eventually it disappears from the con- 

 nective-tissue cells, but whether it is eliminated from the body or 

 used in some altered form we do not know. As it is formed by 

 malarial parasites, it is peculiar to the diseases caused by them. 

 Brown considers that it is formed by the action of a proteolytic 

 enzyme from the parasite acting upon the temoglobin of the 

 erythrocyte, and that therefore it is formed from haematin, a 

 conclusion also arrived at by Carbone and V. Ascoli. 



HSEMOSIDERIN. — -This is the yellow pigment found in the form of 

 yellow granules in the parenchyma cells of the liver, spleen, kidney, 

 bone-marrow, endothelium of capillaries, and occasionally in leuco- 

 cytes, after any great destruction of blood cells. In malaria it is 

 undoubtedly due to the action of hsemolysins destroying the red 

 cells. It contains iron in the form of an inorganic compound, and 

 gives the usual Berlin-blue reaction. It is insoluble in alkalis and 

 acids, but is soluble in alcohol. 



The Blood. — The parasites live in the blood, in which they produce 

 changes by their own action and by that of their toxins. 



The malarial parasites, being true blood parasites and living in 

 the red cells, form the most important feature of the pathology of 

 the blood, but their structure and life-history having already been 

 described in Chapter XVII., it only remains to estimate their 

 numbers. 



Ross estimates that a medium-sized person of 68 kilogrammes 

 (150 pounds) body weight possesses 25,000,000,000,000 er3rthrocytes. 

 In a severe infection he estimated the parasites as numbering 12 per 

 cent, of the corpuscles — i.e., 3,000,000,000,000 — and, further, he 

 considers that if they fall below i to 100,000 corpuscles — i.e., 

 250,000,000 — ^they will cause but little disease. Certainly, large 

 numbers of parasites can exist in the body and go through their life- 

 cycle in the spleen without causing S5miptoms. This condition is 



