PROTOZOA 427 



eosinophilia. Gessard 7 describes a protozoan parasite which 

 he believes to be identical with the protozoon described by 

 Bentley in the polymorphonuclear leucocytes of a dog that was 

 evidently in poor health. He describes it as follows. 



"The parasites are oblong bodies with a smooth regular 

 outline ; they are colorless, motionless and contain no pigment. 

 When stained with Leishman's method a nucleus, protoplasm, 

 and a capsule can be readily made out. The nucleus in some 

 instances is horse-shoe shaped, in others irregularly spherical. 

 The measurements of the body are very uniform, 11 to 12 /* 

 by 4.2 to 5.2 /*." 



COCCIDIA. 



General discussion. Of the sporozoa that occur as para- 

 sites, in the higher animals, coccidia are perhaps of first im- 

 portance. In their young state they exist as non- encapsulated 

 inhabitants of epithelial cells, particularly in those of the in- 

 testinal canal and its adnexa, especially the liver, and more 

 rarely in those of the organs of excretion. Some of the mature 

 forms surround themselves with a capsule and become changed 

 into round or oval permanent cysts or oocysts (Schaudinn), 

 which leave their resting-place and usually their host, and 

 under certain conditions form sickle-shaped sporozoites 

 through the repeated division of their cell body (sporogony). 

 Through the taking-up of sporozoite-containing oocysts into 

 a new host there is produced an infection of the latter, in that 

 the sporozoites are set free and seek out epithelial cells for 

 their further development. 



Besides this form of multiplication there occurs within 

 the infected organ also a reproduction by schizogony that is, 

 there are developed from mature but non-encysted individuals, 

 by means of segmentation, a large number of new sickle-shaped 

 individuals, the so-called. merozoites, which seek out epithelial 

 cells, and develop further in the same. 



Gessard. The Jour, of Hygiene, Vol. VI (1906) p. 229. 



