256 SPOROZOA. 



also, and they (1919) carried out experiments on the develop- 

 ment of P. prsecox under varying conditions of temperature. 



Celli and San Felice (1891) were the first to show that the 

 infection could be transmitted from lark to lark by inoculation 

 of blood from an infected bird to a healthy one. Grassi and 

 Peletti (1891) and Laveran (1891) repeated the experiment 

 in larks, and Ziemann (1898) in another type of bird. Ross 

 (1898 6) showed that mosquitoes fed on sparrows were able 

 to infect crows and larks. Koch (1899 a, 1899 6) showed 

 that parasites naturally occurring in one type of birds can be 

 inoculated into other types of birds. Ruge (1901) and 

 Wasielewski (1908) were similarly able to infect various types 

 of birds, thus showing that the same species of Proteosoma 

 is able to infect a number of different genera and species. 

 According to HuiBP (1927) infections had been noted in at least 

 seventy-nine species of birds belonging to at least fifteen 

 famihes. Originally the malarial parasites of birds were all 

 considered as belonging to a single species, but they have now 

 been spht up into a number of species by Hartmann (1927), 

 Huff (1930), Manwell (1930) and others, and parasites from 

 a large number of different birds have also been described as 

 distinct species. Mayne (1928) has recorded both natural and 

 experimental infections in Anopheles subpictus Grassi {=^rossii). 

 According to Giovannola (1934) no less than four species are 

 known to occur in Passer domesticus (Linn.), viz., P. precox 

 Grassi & Feletti, P. cathemerium Hartmann, P. elongatum Huff, 

 and P. rouxi Ed. & Et. Sergent & Catanei. According to him 

 P. prsRCox is distinguishable by spheroidal gametocytes con- 

 taining pointed pigment granules, and spheroidal schizonts 

 producing 14 to 32 merozoites. 



In recent years a good deal of experimental work has been 

 carried out on infection and resistance in bird malaria (Boyd, 

 1925 ; Taliaferro, 1925 ; Hegner, 1926), on relapses in bird 

 malaria (Manwell, 1929), and on quinine and plasmochin 

 therapy (Boyd, 1926 ; Hegner, Shaw, and Manwell, 1928 ; 

 Manwell, 1930), resulting in the discovery of facts which 

 are of considerable practical importance in the warfare against 

 human disease. 



" Black spores " of Ross. — Certain bodies described as 

 " black spores " were originally noted by Ross (1899, 1905, 

 1923) and Daniels (1900) within oocysts in the stomach of 

 infected mosquitoes, as well as free in the tissues, and even in 

 uninfected mosquitoes. According to Stephens and Christo- 

 phers (1908) they are also found in the thoracic muscles and 

 salivary glands. Castellani and Chalmers (1919) regard these 

 so-called " black spores " as protozoal parasites of the genus 

 JVosema, which have invaded the oocyst. 



