LAVERANIA MALARIA 



169 



2 fjb to 3 /JL. At first they are still in the pale blood corpuscles, later 

 they free themselves and are found in numbers in the peripheral 

 blood in cases of pernicious malaria of Southern Europe and the 

 tropics, while, on the other hand, they occur much more rarely in 

 the peripheral blood in West African malignant tertian. Their further 

 development takes place under the same conditions as in the other 

 malarial parasites. 



FIG. 89, Section through a tubule of the salivary gland of an Anopheles with sporozoites 

 of the malignant tertian parasites ; on the left at the top a single sporczoite greatly magnified. 

 (After Grassi). 



D. Thomson (1914), 1 from studies of autopsy smears, has shown 

 that crescents develop chiefly in the bone-marrow and spleen, and 

 take about ten days to grow into the a'dult state in the internal organs. 

 He believes that crescents are produced from ordinary asexual spores. 

 Quinine, he states, has no direct destructive action on crescents, but 

 it destroys the asexual source of supply. 



The sporozoites of Laverania malaria? (P. falciparum) are repre- 

 sented in fig. 89. 



The principal distinctive characters of the malignant tertian para- 

 site are : (i) The ring forms are very small, occasionally bacilliform, 

 and may be marginal (" accole " of Laveran) ; (2) the larger tropho- 

 zoites are often ovoid, and about one-third or one-half of the 

 erythrocyte in size; (3) the infected red cells sometimes show coarse 



Annals Trop. Med. and FarasitoL , viii, p. 85. 



