igo 



Arthropods as Hosts of Pathogenic Protozoa 



melanin. The haemozoin is the most conspicuous part of the para- 

 site, a feature of advantage in diagnosing from unstained prepara- 

 tions. 



As the schizont matures, its nucleus breaks up into a number of 

 daughter nuclei, each with a rounded mass of protoplasm about it, 

 and finally the corpuscles are broken down and these rounded bodies 



125. Life cycle of the malaria parasite. Adapted from Leuckart's chart, 

 by Miss Anna Stryke. 



are liberated in the plasma as merozoites. These merozoites infect 

 new corpuscles and thus the asexual cycle is continued. The malarial 

 paroxysm is coincident with sporulation. 



As early as Laveran's time it was known that under conditions 

 not yet determined there are to be found in the blood of malarious 

 patients another phase of the parasite, differing in form according 

 to the type of the disease. In the pernicious type these appear as 

 large, crescent-shaped organisms which have commonly been called 

 "crescents." We now know that these are sexual forms. 



