412 SPECIFIC MICRO-ORGANISMS 



horses, sheep and swine are also susceptible and serious epizootics 

 of coccidiosis due to E. stiedce have been observed in cattle. 



Eimeria (Coccidium) Schubergi. This coccidium occurs in 

 the intestine of a common myriapod (thousand-legged worm). 

 Lithobiusforficatus. It is the organism in which Schaudinn worked 

 out the life-cycle now regarded as typical for Eimeriadse, and 

 which corresponds very closely to that of E. stiedce. (See Fig. 

 78, page 156). 



Haemoproteus Columbae. Celli and Sanfelice in 1891 observed 

 this organism in the red blood cells of doves. It is widely dis- 

 tributed as a parasite of wild doves and has been found in Europe 

 and in North and South America. The life-history of the parasite 

 in the vertebrate host and its mode of transmission by flies of the 

 genus Lynchia has been most fully studied by Aragao. 1 In the 

 circulating blood of doves the organism is most commonly seen 

 as a large crescent-shaped structure occupying most of the interior 

 of an erythrocyte and crowding the nucleus of the latter to one 

 side or encircling it. The outline of the erythrocyte and the out- 

 line of its nucleus are not distorted. The parasites are definitely 

 recognizable as females and males, macrogametocytes with granu- 

 lar, deeply staining cytoplasm and microgametocytes with a 

 paler cytoplasm. When these are ingested by the fly along with 

 its blood meal, the gametes arise, fertilization takes place and 

 there is produced a creeping ookinete which apparently does not 

 penetrate the intestinal wall in the fly or indeed undergo any 

 further development there. It gains the blood stream of a new 

 host, especially young nestlings, when the fly bites them. It is 

 taken up by a leukocyte which comes to rest in the pulmonary 

 capillaries of the young bird. Here the parasite produces a very 

 large cyst and divides to form very numerous minute sporozoits. 

 When the cyst bursts these sporozoits gain the blood stream, 

 penetrate erythrocytes and grow to produce the gametocytes 

 again. The asexual cycle of schizogony seems to be lacking. 



This organism is important as a typical example of Hcemo- 



1 Archi. /. Protistenkunde, 1908, Bd. XII, S. 154-167. 



