62 FEEDING WITH CYSTICERCUS TENUICOLLIS. 



intestines of puppies of the same litter as those I had used in 

 my other experiments, and have never found Tcenia serrata in 

 them ; but, on the other hand, I have very commonly met with 

 Ascaris marginata and Tcenia ci^cumerina. I must here remark 

 that I only made use of parlour and house dogs for my purpose, 

 and it is in these that both the above-named parasites ordinarily 

 appear, the Tcenia serrata more commonly infesting hunting dogs. 

 Still further confirmation of my view is afforded by the impor- 

 tant circumstance that after feeding the dogs with Cysticercus 

 pisiformis, the number of tape-worms of the species Tcenia 

 serrata, which were found more or less developed in their digestive 

 canal, agreed exactly with the number of Cysticerci I had given. 

 Another circumstance worthy of observation, and strongly con- 

 firmatory of my view, is, that the size and the condition of 

 development of the Tcenia serrata in the intestine of the dogs 

 that had been fed with Cysticerci, exactly corresponded with the 

 time that had elapsed since the period of feeding. 



2. EXPERIMENTS OF FEEDING WITH CYSTICERCUS TENUICOLLIS. 



The slender-necked Cysticercus is very commonly met with in 

 the viscera of our fat cattle ; as regards its caudal vesicle it is the 

 largest of all the Cysticerci, for this often attains to the size of a 

 fist, whilst its head never exceeds that of an ordinary Cysticercus 

 in circumference. As these Cysticerci were generally brought 

 to me enclosed in their cysts, and as the walls of the cysts were 

 penetrated by a great deal of fat, I always disengaged the tape- 

 worms from their investments before I fed the dogs with them. 



First experiment. In the beginning of May, 1852, I made my 

 first preliminary experiment of feeding with iheCysticercus tenuicollis 

 upon a young hound ten weeks old, to w r hom I gave six Cysticerci 

 within four days. A few days afterwards I found, in this dog's 

 intestine, only the head ends of the ingested worms. They were 

 from one to one and a quarter line in length, and consisted of 

 the head and solid neck of the former cystic worm, of which the 

 scolex had alone escaped digestion. In order to ensure the 

 greater success of my experiments, I each time cut off before- 

 hand the voluminous caudal vesicle of the selected tape-worms, 

 and only fed the dog with those which had the neck and head 

 involuted in the cylindrical and hollow body. 



Second experiment. On the llth May, a second young hound 



