414 SPECIFIC MICRO-ORGANISMS 



proteus, as it is the one species of this genus in which the life cycle 

 has been most completely studied. 



HaBmoproteus (Halteridium) Danilewskyi. Grassi and 

 Feletti 1 first clearly recognized this organism as a definite malarial 

 parasite of birds. It is widely distributed and has been found in 

 very many different birds, including sparrows, doves, owls, robins, 

 blackbirds and crows. The life history is imcompletely known. 

 In the blood of the infected bird the organism first appears as a 

 small oval or lance-shaped body within the cytoplasm of an ery- 

 throcyte. This enlarges, without distorting the outline or dis- 

 placing the nucleus of the blood-cell, and stretches along one side 

 of the cell. It curves about the nucleus and is enlarged at either 

 end when fully developed. Two types, macrogametocytes and 

 A B c 



FIG. 183. Hamoproteus danilewskyi. A and B, Fresh triple infection of red 

 blood cells. C, D and E, Growing parasites, the last two showing vesicular nuclei. 

 jF, Full-grown halteridium with two nuclei. (After Doflein.} 



microgametocytes, are easily recognizable in stained prepara- 

 tions. If blood containing these mature halteridia is diluted 

 with citrated salt solution and studied under the microscope the 

 further changes in the sexual cells may often be followed. Each 

 gametocyte bursts the erythrocyte enclosing it and assumes a 

 rounded outline. In the microgametocyte the protoplasmic 

 granules exhibits violent agitation and several fine filamentous 

 processes suddenly shoot out from its periphery and lash about. 

 After a few moments these microgametes separate completely 

 and rapidly swim away. Meanwhile, the macrogametocyte has 

 escaped from its erythrocyte and come to rest in a rounded condi- 

 tion. A microgamete approaches and penetrates the macro- 

 gamete, and in a few minutes this fertilized sphere elongates into 



1 Cenlralbl.f. Bakt. 1891, Bd. IX, S. 403-409; 429-433; 460-467. 



