l62 MALARIA [CH. 



" crescents " were known for many years before their true 

 nature was discovered. On being taken into the gut of a sus- 

 ceptible species of mosquito, the gametocytes escape from the 

 red cells and give rise to the gametes. The macrogamete is 

 vermiform, whilst the microgametocyte becomes spherical 

 before giving rise to the microgametes. The cycle of develop- 

 ment in the mosquito at the most favourable temperature, 

 28-30° C, is complete within eight days. In this species 

 development cannot take place below 18° C, and consequently 

 it is only found in warm countries, the disease to which it gives 

 rise being often known as " Malaria Tropica." The develop- 

 ment of P. falciparum in the mosquito is more easily followed 

 than that of the other species of malarial parasites, for when a 

 mosquito is susceptible to this species, as in the case of 

 A. {Myzomyia) Christopher si, practically all the insects become 

 infected when fed on a patient suffering from this infection. 



In consequence of the comparatively high temperature 

 required for the development of P. falciparum within the 

 mosquito, the disease does not occur in temperate regions 

 except during the summer. Usually associated with P. vivax, 

 it is found throughout the whole of the tropics, except in regions 

 hke the Sahara, where mosquitoes are absent owing to the lack 

 of water. 



LITERATURE. 



The more important and accessible general treatises upon malaria, 

 and papers dealing with recent work upon epidemiology and preventive 

 measures against malaria. 



tBahr, P. H. (1913). Malaria in Kurunegala. Report Colonial Office. 



April, 191 3. 

 •j-Bentley (1910). Malaria in Bomia^/ (Report) . Govern. Central Press, 



Bombay. 

 fCelli (1901). Malaria according to the New Researches. Longmans, 



Green & Co. London, 1901. 

 f Christophers. Malaria in the Punjab. Scientific Memoirs by Officers 

 of the San. and Med. Depart, of the Gov. of India, No. 46. 



•f Malaria in the Andamans. Ibid. No. 56. 



Christy. Mosquitoes and Malaria. Good elementary account. 

 Craig {1909). The Malarial Fevers, Hcsmoglobi nitric Fever and the Blood 

 Protozoa of Man. 

 t Works representative of the more recent lines of investigation on malaria. 



