394 



TR YPA NOSOMIDM 



term ' Trjrpanosoma ' to it, so that it becomes the type species of the genus, 

 from which any variation in the classification of the species must be made. 



Ogawa has studied this parasite in the frog in 19 13, as well as Doflein and 

 MendeleefE-Goldberg. 



Gruby's Original Description. — ' Its elongated body is flattened, transparent, 

 curved like a centre-bit; the cephalic end is terminated in a thin, elongated 

 filament ; the caudal end is terminated also in a pointed filament. The length 

 of the animal is 40 to 80 jw, its breadth is 5 to 10 jjt, the filamentous pointed 

 cephalic end has the greatest mobihty, the length of the cephalic filament 

 is 10 to 12 /x; its body is elongated, flat, and toothed like the blade of a saw 

 all along the length of one of its margins; it is, as I have above mentioned, 

 supple and twisted two or three times around its axis, like an auger or a 

 corkscrew, which is the reason why I propose to name this haematozoon 

 " Trypanosoma." ' 



Zoological Distribution. — It has been found in Rana esculenta Linnaeus, in 

 R. temporaria Linnaeus in Europe; in R. speciosa in the Congo; in R. trinodis 

 in the Gambia. Whether the species found in Hyla arborea are truly T. rota- 

 torium or not is uncertain. 



Morphology. — The pleomorphism exhibited by 

 this form is so varied that it requires classification, 

 for, as Chalachnikov has shown, the following 

 varieties exist: 



1. Flattened Forms. — [a) Simple plain forms; 

 (&) plain forms rolled on themselves; (c) spiral 

 forms. 



2. Pectinated Forms. — {a) Pectinated spiral forms ; 

 (6) cornucopial forms. In all these forms the 

 undulating membrane is much folded, and has a 

 thickened edge. The flagellum, which is short, 

 starts from the kinetonucleus, which is situate at 

 a variable distance from the aflagellar extremity. 

 The trophonucleus is round or oval. The usual 

 length varies from 40 to 80 pi, the breadth from 

 5 to 40 jx, and the flagellum is about 10 to 12 /x long. 



-c^ _ Doflein finds that in the blood and internal 



l^iG 93-- -i^yp«-^o5oma f g intermediate between the flagellate 



yotatonum Mayer. non-flagellate organisms are found^ The 



(After Button and latter cannot divide. 



Todd.) Life-History. — The life-history is but little 



known. Asexual multiplication takes place by 

 the trypanosome becoming round and losing its locomotor apparatus, 

 and dividing by mitosis. It is but rarely inoculable into other frogs, 

 but it grows in cultures, especially upon Novy-McNeal's medium, but 

 the cultures are not inoculable. In the cultures leptomonas and rosette forms 

 are seen. The researches of Fran9a show that it is capable of developing in 

 the leech {Helobdella algira), in which it gives rise to leptomonas-like forms, 

 which are to be seen located against the walls of the gastric intestinal pouches. 

 Frogs can be infected by the bites of infected leeches or by the inoculation 

 of the intestinal contents. 



Cultivation. — It has been cultivated in acid bouillon - blood media by 

 Pouselle in 191 7. 



Classification. — The question is unsettled as to whether there are more than 

 one species included under the term T. rotatorium. 



Pathogenicity. — It is believed to be non-pathogenic. This immunity of 

 the frog has been stvidied by Doflein and others. 



Classification. — If the section on evolution contained in Chapter V. 

 be read, it will be seen that we believe that new diseases can arise 

 at the present time; that organisms usually harmless in a given 

 environment may become so altered under certain circumstances 



