88 Mosquitoes 



with few exceptions, can be reared on nutrient media 

 such as bouillon or gelatin. The protozoa can get 

 out of the body of an animal, human or otherwise, 

 in only one way, by the aid of the mosquito. Within 

 this insect they complete their life cycle and by its 

 aid they are again transmitted to the proper host. 

 In the case of bird malaria the carrier is a Calcx ; in 

 the case of human malaria, an Anopheles. ISIo pro- 

 tozoan parasite can possibly pass from host to host 

 of one species without the intervention of an animal 

 of another species. In the case of sporozoa passing 

 through a stage between hosts in the free air, this 

 stage is as an encysted spore ; all the growing is done 

 in one host or the other. The malaria parasite does 

 not encyst nor resist drying. 



Transmission of Malaria. — We make a great 

 fuss about mosquitoes giving us malaria, but as a 

 matter of fact it is the mosquito that has the malaria, 

 and that is the " primary host," in which the spore 

 matures, conjugates, and produces the stage when 

 it may be passed on to man ; therefore we are the 

 pests who give malaria to the mosquitoes. 



In from seven to fourteen days after the poor, 

 unsuspecting creature has bitten a human being with 

 blood full of crescents or pigmented spheres, it is 

 able to retaliate, having a salivary gland full of 

 parasites, so that the person bitten by that mosquito 

 will develop his case of chills in anywhere from two 

 days to three weeks, according to the dose of para- 

 sites received, their kind, and perhaps also the 

 patient's natural resistance or vitality, as different 

 people are more or less immune. 



