528 A MANUAL OF BACTERIOLOGY 



Plasmodium prsecox 



Syn. Proteosma Grassii, Hcemamoeba relicta. 



This parasite (commonly called " proteosoma ") is met with in 

 sparrows and other birds, in which it invades the red blood-cor- 

 puscles, and its structure and development are practically identical 

 with those of the benign malarial parasites of man. It grows from 

 a minute granule into an amoeboid plasmodium, which ultimately 

 segments and forms a rosette. In some specimens of blood flagel- 

 lated male gametocytes make their appearance, similar to those 

 of malaria, the flagella break away from the main mass, fertilise 

 other non-flagellated or female cells, and a series of changes ensues 

 analogous to those occurring in the malaria parasite (p. 516). The 

 fertilisation and development of the fertilised cell take place in the 

 stomach of a mosquito (Culex fatigans), by which the infection is 

 transmitted to other birds. 



Halteridium Danilewskyi 



This is an elongated, curved parasite (also known as Hcemo- 

 proteus or Hcemamoeba Danilewskyi}, found in the red corpuscles of 

 certain birds (pigeon, crow, etc.), and embracing the nucleus (Plate 

 XXV. b). By some it is included among the malaria-like parasites 

 (Plasmodium). At an early stage it much resembles the proteosoma, 

 but as it grows it becomes elongated, pigment -granules appear, 

 and are either scattered throughout the protoplasm or collect in 

 two groups, one at each extremity. Finally, the parasite occupies 

 nearly the whole of the corpuscle, dislocating its nucleus. The 

 fully grown parasites may be differentiated into two forms, one 

 of which remains almost completely unstained when treated with 

 methylene-blue, the other staining deeply with this dye (Opie). 

 When the blood is withdrawn, the corpuscles disintegrate and 

 liberate the contained parasites, which assume a circular outline, 

 and a certain number become flagellated. It is only the non-staining 

 form which becomes flagellated. These two varieties of the parasite 

 are the male and female cells respectively, and the fertilisation of 

 the female cell by a free flagellum has been actually observed by 

 MacCallum. 1 It can hardly be doubted that the development of 

 the fertilised cells takes place in some insect, but the definitive 

 host has not yet been discovered with certainty. 



The presence of these parasites induces rise of temperature, 



1 Journ. Exper. Mecl, vol. iii, 1898, pp. 79, 103, 117. 



