1'84 ANIMAL PARASITES AND MESSMATES. 



In the creche the parasite is on its passage from one 

 station to another, and that which arrives at the lying- 

 in asyhim has reached the end of its journey and is 

 at home. We have proposed to give it the name of 

 Nostosite, as distinguished from that which only inhabits 

 its host for a time. We may also remark that the same 

 animal may give lodging to these two kinds of parasites. 

 It is thus that the rabbit harbours in its peritoneum 

 passengers which are only at home in the dog ; and, inde- 

 pendently of these passengers (these strangers may we 

 say ?), it lodges in its intestines a sexual tgenoid worm. 

 The first is a Xenosite, the second a Nostosite. The 

 mouse, in the same manner, gives lodging to passengers 

 under the name of Cysticerci, which are destined to the 

 cat in order to become Twnise. 



We might call the rabbit or the mouse which har- 

 bours worms in transitu, the stage coach ; more especially 

 as from time to time there are some which miss it, and 

 are consequently lost in their peregrinations. 



This stage-coach is the intermediate host, the Zwis- 

 chemcirth of German helminthologists, which is always 

 an animal with a vegetable diet; the final host is gene- 

 rally a carnivore : it is by means of the vegetable 

 feeder, the grazing or herbivorous animal, that the 

 stranger parasite introduces itself. 



The result of this is, that the carnivore receives into 

 its house, every time that it devours its prey, all the 

 parasitical inmates of the latter, and the walls of its 

 digestive canal form the soil in which are implanted all 

 the worms which can take root there. The tissues of 

 the prey are triturated and digested, but the worms 

 which it encloses escape the action of the gastric juice, 



