CHAPTER XVI 



THE HjEMOSPORIDIA 



TECHNICAL SUGGESTIONS 



For most classes it is necessary to precede the study of malarial 

 parasites and related forms by a study of the morphology of the blood, 

 with particular attention to the types of leucocytes. Otherwise, the 

 student is very apt to confuse the nuclei of these cells with the para- 

 sites for which he is searching. 



In this country it is rarely possible to demonstrate the living 

 malarial parasites of man. If such an opportunity presents itself, 

 a preparation should be sealed with vaseline and movements of the 

 organism and pigment granules demonstrated. Mature parasites 

 if kept on a warm stage may be seen to sporulate. 



Stained preparations of Plasmodium vivax and P. falciparum are 

 widely obtainable from dealers. Less frequently, demonstration 

 specimens of P. malaria? may be purchased. In some parts of the 

 country endemic malaria still occurs, and even in malaria-free sections 

 the widespread use of induced malaria in treatment of paresis affords 

 occasional opportunities for obtaining material from hospitals and 

 clinics. In such cases smears should be made at 12-hour intervals 

 beginning immediately after a chill and continuing through the cycle. 

 Stain with Wright's stain (p. 110). 



Plasmodium prcecox and related species are found in English 

 sparrows in this country, although natural infections do not seem 

 common. Laboratory strains have long been maintained in canaries 

 in various laboratories and infected birds may be obtained from some 

 of the dealers listed on page 124. The parasites are abundant only 

 during the acute stages of the infection and hence fresh birds shoidd 

 be inoculated a week or so before needed for laboratory work. This 

 is done by pricking a vein under the wing or in the leg of the infected 

 bird, sucking up a drop of blood into a syringe containing physiological 

 salt solution, and injecting into the breast muscles of the clean bird. 



The sexual cycle in the mosquito can be obtained by the methods 

 given in detail by Huff, 1927. Reared females of Culex pipiens are 

 kept away from water for 24 hours and then allowed to feed on 

 heavily infected canaries at night. The feathers of the bird should 

 be parted in the pectoral region and wetted down. It is immobilized 

 by tying it snugly in a piece of netting and then placed on the crino- 

 line-gauze top of a lantern-chimney breeding cage in such a way that 

 its exposed breast is accessible to the mosquitoes. A strip of cloth is 

 placed over it and extended down along the side of the hintorn globe 



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