PROBLEM 4. H01V We Atteiiipt to 



the blood stream. It is the toxin that pro- 

 duces the characteristic chills followed 

 by fever. Each spore now repeats the 

 cycle; it glides into a new corpuscle, 

 feeds, grows, reproduces; then the cor- 

 puscle bursts. When this happens a num- 

 ber of times, a great many of the cor- 

 puscles are destroyed. As a result the 

 infected person looks pale and anemic 

 (lacking hemoglobin). He will feel tired 

 because oxygen is not being circulated 

 properly for oxidation. If he does not 

 receive drugs, such as quinine or ata- 

 brine, death may follow. 



The malaria protozoan's life story — 

 second chapter. In the meantime other 

 Anopheles mosquitoes are likely to have 

 bitten the person with malaria. As a 

 mosquito bites, it sucks up some of the 

 blood and swallows it. If there are many 

 parasites in the body it is likely that the 

 mosquito will suck up some of them. 

 When the parasites get to their new sur- 

 roundings in the mosquito's stomach 

 they lose their pseudopods and take on a 

 spherical form; then they develop into 

 two types, male and female. Some re- 

 main spherical; these are the females. 

 Some develop small whiplike projections, 

 each of which has a nucleus and is really 

 a cell; these are the males. In Figure 3 1 1 

 there are drawings of a male cell pierc- 

 ing a female cell and fusing with it. The 

 fused cell bores its way into the wall of 

 the mosquito's stomach. Then it divides 

 many times. The new protozoa, pro- 

 duced by division, grow. As they 

 occupy more space they push out a kind 

 of pocket, a large swelling on the outer 

 wall of the stomach. Examine Figure 310 

 again. After some time this pocket bursts, 

 and many of the protozoa are released 



Stop the Spread of Disease 



Fertilized cell 



351 



Fig. 311 How the protozoan chafiges in the 

 mosquitoes stomach. Does A change into male or 

 j em ale? Where are the two cells shown fusing? 



into the body cavity of the insect. From 

 here they travel to the salivary glands. 

 The next time the mosquito bites a per- 

 son some of the parasites will enter with 

 the bite. Do Exercises 7 and 8. 



Mosquitoes and yellow fever. "Yellow 

 Jack" or yellow fever was a great 

 scourge in the tropics until man learned 

 to fight not the cause but the carrier. It 



