THE EX.IMIXATION OF THE BLOOD 609 



THE VARIETIES OF MALARIAL PARASITES. 



There are three to look for : — 



The benig^n tertian parasite full\' i^r.nxn in fort\-eight hours. 

 The subtertian, t-estivo-autumnal or malignant parasite, fully- 

 grown in tliirty-four to forty-eight hours. 

 The quartan parasite full^' grown in seventy-two hours. 



There may be several " crops " of one parasite, so that the same 

 slide may show two or three groups at different ages. 



There may be a multiple infection, two varieties of parasites in the 

 same film. 



One family of parasites may be so few in number that there will 

 be no corresponding rise of temperature. 



If there are two infections of the same varietv the rises of tempera- 

 ture are seldom equal. 



In benign tertian the red corpuscle is enlarged and pale. 

 Schiiffner's dots ma\' be seen, which, consist of peculiar granular 

 degeneration staining brick red and diagnostic of benign tertian. 

 Parasites are plentiful in the peripheral blood, but tend to sporulate 

 in the deeper organs; the gametocvte is rounded or ring-shaped, fifteen 

 to twenty-five spores, yellow brown, pigment coarse. Active amoeboid 

 movement. Life-cycle forty-eight hours. 



In the subtertian the red cell is smaller, no St-liiiffner's dots. 

 Young ring forms are seen in the peripheral blood, but not always; 

 it matures in the deeper organs. The sporulating form found in the 

 spleen ma}' be seen in the peripheral blood just before death. The 

 corpuscle becomes yellow — " brassv bodA-." The gametocyte is 

 crescentic in shape, pigment black and fine. It is very amoeboid. 

 Life-cycle is variable, perhaps thirty-four to forty-eight hours. 



Spores, 7-8, rarely 20. Very active, but small processes. 



The male and female cells can be distinguished. 



Male, has pigment and chromatin more scattered. 



Female, one central mass of chromatin with the granules arranged 

 around it. There ma}- be two or three or more small, clean-cut ring 

 forms in 'one cell which is rare in benign tertian or quartan. 



Some subtertian parasites mav be seen that have not penetrated 

 the red cell which is uncommon in benign tertian. 



The chromatin is more flattened, and not knob-shaped as in benign 

 tertian. 



A second slide taken twenty-four hours later \\-\\\ show parasites 

 enlarged if benign, but the\- will be little altered or gone to the deeper 

 organs to sporulate if subtertian. 



In benign tertian and quartan there are usuallv a few earlv or late 

 sporulating parasites which would not be seen in subtertian. 



