94 



DISEASES DUE TO PROTOZOA 



Irregular Sub continuous Benign Tertian Fever. 



Parasites may mature at different times of the same day, thus pro- 

 ducing a somewhat continuous fever with remission and exacerbations. 

 In this respect it may resemble subtertian fever. 



Irregularities may also be caused by a mixed infection of other 

 types of malarial parasites. 



Simple Subtertian Malarial Fever. 



The parasite is Laverania malarise. 



The cycle is probably twenty-four to forty-eight hours. 

 These are crescent-forming, and all are malignant. 

 The subtertian parasite is much smaller than the tertian or quartan, 

 occupying as it does half to three-quarters of the red cell. 

 The early unpigmented stage is difficult to see. 

 The amoeboid movements are very active at first. 



Double tertian. 



The parasite settles down later and forms small colourless rings. 



Multiple infection of individual cells is common, much more than 

 in other types, owing perhaps to the enormous number present at the 

 same time. 



The invaded corpuscle seems to be filtered out by the capillaries and 

 small arteries of the deeper viscera and bone-marrow ; hence few are 

 seen in the peripheral blood. 



The segmented form is very rarely seen in the blood. 



It has ten to twelve segments. 



The invaded cells shrink, become darker, sometimes crenated or 

 folded, when they are known as " brassy " bodies, when the parasites 

 may be made out as small minute pale rings. 



The gametocyte is crescent-shaped, and in this is unique. 



A week may elapse after the small intracorpuscular parasites have 

 been seen before crescents are formed, probably not until the pabulum 

 has been exhausted by swarms of endogenous parasites, so that the 



