H^EMOSPORIDIA 



155 



and oval in other forms referred to this group. Piroplasms are 

 transmitted by ticks. These parasites are described at length on 

 p. 172. 



m 



FIG. 79. Leucocytogregarina cants. Life-cycle diagram. Constructed from drawings by 

 Christophers. (After Castellani and Chalmers.) Schizogony occurs in the bone-marrow. The 

 parasite is transmitted from dog to dog by the tick, Rhipicephalus sanguineus, development 

 in which, so far as known, is shown on the right. 



THE MALARIAL PARASITES OF MAN. 



Malaria, otherwise known as febris intermittens, chill-fever, ague, 

 marsh fever, paludism, etc., is the name given to a disease of man, 

 which begins with fever. It has been known since ancient times and 

 is distributed over almost all the world, although very unevenly, but 

 does not occur in waterless deserts and the Polar regions. In many 

 places, especially in the civilized countries of Central Europe, the 

 disease is extinct or occurs only sporadically, and large tracts of land 

 have become free from malaria. 



The rhythmical course of the fever is characteristic. It begins 

 apparently suddenly with chilliness or typical shivering, whilst the 

 temperature of the body rises, the pulse becomes low and tense and 

 the number of beats of the pulse increases considerably. After half 

 to two hours the heat stage begins. The patient himself feels the rise 

 of his temperature (shown by feeling of heat, dry tongue, headache, 



