17 



Tryanosoma gambiense cause of "sleeping sickness" of man; 

 T. evansi causes "surra" a fatal disease affecting especially horses 

 and mules in the Philippines, India; T. equiperdum produces "maladie 

 du coit," or "dourine," a venereal disease of horses, of which there 

 have been serious outbreaks in this country. T. lewisii is apparently 

 harmless parasite of rats, the world over. 



Spirochaeta recurrentis Lebert, 1874. (S. obermeiri Cohn 1875). 

 The cause of European relapsing fever of man. The organism as 

 seen in the blood is a slender, flexible spiral, pointed at the ends, 

 with an undulating membrane, but without cilia. Transferred by 

 bite of the bed-bug. Long classed with bacteria but differ in pos- 

 session of undulating membrane, reproduction by longitudinal 

 division and in biological characters. See Nuttall, '08. 



Related species — A number of species infesting man and animals 

 are known. Disease known collectively as "spirochsetoses." In 

 cases best known the parasites are transferred by ticks. 



Trichomonas — Several species of this genus live in alimentary 

 canal of mammals, birds, snakes, batrachians and lizards. Usually 

 small, pear shaped; with three or four cilia arising from the anterior 

 end and an undulating membrane which runs spirally around the 

 body. 



Lamblia intestinalis — Parasite of man and various animals, and 

 in some cases supposed to cause dysentery. Anterior end of parasite 

 hollowed out to form a saucer-like depression, which fits over the 

 epithelial cells. About this depression six flagella and posteriorly, 

 two others. Cysts containing two individuals to be found in feces. 



Sub Phylum INFUSORIA 



Balantidium coli In rectum of man and swine. Usually associa- 

 ted with intestinal diseases when found in man, but causative action 

 disputed. 



Form and structure — Large, 200/^- long by 50/^- wide, resembling 

 somewhat a Paramcecium. Body covered with cilia which are longer 

 and coarser about the peristome or "mouth." Ectosarc and endo- 

 sarc distinct, body with longitudinal striae, or "myonemes." Two 

 contractile vacuoles. Nucleus bean- or kidney -shaped. 



Reproduction — By simple cross-division. Conjugation occurs. 

 Encysted forms to be found in feces. 



