MICROBIAL DISEASES OF MAN AND ANIMALS. 



68 3 



blood is being sucked. The entry of a sporozoite within a red cell recommences the 

 cycle of development which has just been described If the adult sexual parasites are 

 not taken up by a mosquito they die, but some of the female forms may live for years 

 and then divide, without a precedent fertilization, to produce several young parasites. 

 It is possible for sporozoites to enter eggs lying in the ovaries of infected mosquitoes; 

 it is probable that mosquitoes, hatched from such eggs, inherit the infection from their 

 parent and that they, also, are able to transmit malaria. 



In fresh preparations of blood, a malarial parasite is seen as a body of varying size, 

 which is more refractile and of a lighter color, than the red cell which contains it. It 



<3 



SCHIZOCONY (Asexual Generation) 

 in MAN. 









*>& @ w 



(&}Microyamete 



Sporozoites. 



SPOROCONY (Sexual Generation) 



in the MOSQUITO 



uermiculc. 

 Oocyst. 

 Oocyst with Sporobiasts. 



FIG. 126. Diagram illustrating the human and mosquito cycles of existence of 

 the malaria parasite. (After Martin's General Pathology from Jackson.') 



has distinct amoeboid movement and the pigment granules lying in it are in active 

 motion. In preparations, stained by a modification of Romanowsky's method every 

 malarial parasite is seen to possess a definite purple nucleus surrounded by blue-stain- 

 ing cytoplasm. Young parasites measure less than a fifth of the diameter of a red cell 

 in width; adult parasites may completely fill the cell which contains them. Malarial 

 pigment is the waste product which results from the digestion of the haemoglobin of the 

 red cells by a malarial parasite; consequently, since they have digested more haemo- 

 globin, the older parasites contain more pigment than do the younger ones. A mature 

 asexual parasite is segmented into a number of divisions, each of which becomes a 



