94 



described as members of this genus several authors have separated 

 out certain forms into separate genera. 



Luehe (1906) has recently placed the trypanosomes of mammals 



in the 



Genus TRYPANOZOON Luehe, 1906. 



One of these species {Trypanozoon gamUeThse, usually known as 

 Trypanosoma gambiense) is the cause of "sleeping sickness" in man, 

 and has been transmitted in laboratory experiments to rats and mice. 



Just what practical importance there may be in the ability of the 



Fig. 20. — An Isolated pork-measle bladder worm ( CyHicercus cellulosae), with extended head. Greatly 

 enlarged. (After Stiles, 1898a, 90, fig. 7fi.) 



parasite to live in rats and mice remains to be seen, but theoretically 

 this biological factor may possibly become one of considerable magni- 

 tude. At present the least conclusion to be drawn is that it adds 

 one more to the many arguments in favor of a world-wide destruc- 

 tion of rats and mice. 



Several trypanosomes, other than Trypanozoon gambiense, are 

 transmissible by experiment to rats and mice, while one species {Try- 

 panozoon lewisi) has rats for its normal host, and two other species 

 {Trypanozoon duttoni and Trypanosoma musculi Kendall, 1896) are 

 reported originally from the mouse. 



