MALARIA OF BIRDS. 669 



number of parasites (tertian fever). In such 

 cases large numbers of the parasites die before 

 they reach maturity, their death being indicated 

 by shrinking and clouding of the cells and altera- 

 tions in or disappearance of the chromatin. It is 

 somewhat characteristic of quartan fever, and still 

 more so of sestivo-autumnal, that the sexual cells 

 are much more numerous in recurrences than in 

 primary attacks. One may be able to differentiate 

 a relapse from the primary attack by the number 

 of sexual cells encountered (Euge). 



Nothing in the way of serotherapy has been 

 accomplished, and it is doubtful if any serum 

 could equal quinin in efficacy. 



MALARIA OF BIRDS. 



Diseases considered to be true malaria also occur in 

 birds. 



One of these diseases is caused by a proteosome (Pro- Proteosome. 

 teosoma Labbti, Cystosporon danielewsky, Hemameba re- 

 licta). Sparrows, hawks, buzzards, crows and pigeons 

 are affected. Like the malarial parasites in man, the 

 parasite enters the erythrocytes and has both a sexual 

 and an asexual cycle of development, the latter taking 

 place in the infected animal, the former in the stomach 

 of the common mosquito (Gulex pipiens) . Hence in its 

 development proteosoma is perfectly analogous to 

 plasmodium. This disease is transmissible from bird to 

 bird by the inoculation of infected blood. 



Halteridium is still another hemosporidium which in- Halteridium. 

 fects birds. It was in the study of this organism that 

 MacCallum first saw the phenomenon of impregnation. 

 All the cells seen in the blood appear to be divisible into 

 male and female, and although MacCallum had seen im- 

 pregnation in microscopic preparations the life cycle for 

 a long time was obscure. Recently Schaudinn has found 

 that the sexual cycle is completed in Culex pipiens. He 

 considers the organism to be a trypanosome. "I have 

 been able to prove that the halteridium is the sexual 



