3i8 



which distinguish the male and female gametes 

 of the malaria parasite. 



(i) The male cell possesses a mass of compact 

 chromatin and faintly staining protoplasm. 



(ii) The female cell possesses but little chro- 

 matin, but stains deep blue (Romanowsky). 



Flagellation. — (i) This can be observed in' 

 a simple wet film preparation. Make stained 

 specimens according to the method given on p. 31, 

 or 



(ii) Use artificial serum (bird's serum, one 

 part ; salt solution, o'6 per cent., nine parts), and 

 to this add a trace of bird's blood. Make a series 

 of hanging drops in moist chambers. Dry, fix, and 

 stain, from time to time, according to stage of 

 development, observed microscopically. 



Further stages of development (vermiculi) 

 have not been observed on the slide. 



Development of Vermiculi. — (i) Determine 

 what species of Culex is the suitable one for the 

 process of development. C. nemorosus was used 

 by KoCH, in Italy. C. fatigans is also a carrier. 



(ii) Collect the Culex that have fed on 

 sparrows, etc., roosting at night in trees. The 

 Culex can be caught in large nuilibers in shaded 

 drains, under bridges, in outhouses, etc., and ex- 

 cellent material is in this way easily got. Identify 

 the species of Culex that is infected. 



(iii) For the method of feeding mosquitoes 

 on birds' blood, vide p. 102. 



Twelve to fifteen hours. — Vermiculi in all 

 stages of development are found in the stomach ; 

 a conical projection arises from the fertilized 

 gamete. This gradually elongates, forming a long,, 

 curved, oval body, the complete vermiculus. The 



