58 FEEDING EXPERIMENTS. 



cestoids, has been proved by Kiichenmeister, of Zittau, by experi- 

 ments first made by him, and published in various medical and 

 natural history periodicals. 1 It was a very happy thought of his 

 to institute experiments of feeding animals with Cysticerci. I 

 have repeated and extended these feeding experiments, and can 

 substantiate what Kiichenmeister was the first to make known, 

 viz., that certain cystic Entozoa become Taenice in the intestinal 

 canal of dogs. 



The chief condition for the success of these experiments is, that 

 the cystic worms should be lively, or at least capable of being 

 revived when administered ; to which end they must be made use 

 of directly, or at the most a few hours after, the death of those 

 animals which yield them. As long as the organs of the mam- 

 mals in which these parasites abound remain warm, one may be 

 sure that the worms are still living ; with the cooling of the 

 infested organism, they become gradually languid, and at last 

 seem quite dead, but from this state they can be restored to 

 life, even after the lapse of several hours, by the application of 

 warmth. When I was not certain w r hether the cystic worms 

 I was using for my feeding experiments were still living or not, 

 I threw them into luke-warm water, and then only made use of 

 those individuals which had by this means been re- animated. 



To produce tsenioid worms out of cystic worms, I caused the 

 latter to migrate passively into the intestinal canal of puppies by 

 feeding these with them. Puppies of about a week or two old 

 were most suitable. They lapped up the milk in which the 

 cystic worms were mixed very readily ; those which exhibited no 

 particular appetite at the moment had their jaws held open and 

 the milk poured down their throats, so that the swallowing of the 

 worms was secured. At first I made use of cats, rabbits, and 

 Guinea-pigs, also, for these experiments ; but they afforded me no 

 satisfactory results. 2 But the dog, as I shall presently show, is 

 by his mode of life naturally obnoxious to those cystic worms 

 with which I experimented, and hence the experiments with 

 puppies necessarily succeeded. 



1 The first notice is given in Giinsburg's ' Zeitschrift fur Klinische Vortriige,' 1851, 

 p. 240. 



2 All the feeding experiments cited in the following pages were carried on in the year 

 1852. 



