MTGllATION OF ENTOZOA. 273 



of whicli Lave in fact been admitted simply with a theoretic 

 view.^ 



Nevertheless, j\I. V. Beneden may be assured tliat if las 

 Taenia Camtrus be really a distinct species — a fact of whicli 

 we have much doubt — that is the species employed in our 

 experiments. We have strictly administered the same species 

 as that which we have found in our dogs after we had given 

 them ceenuri. Moreover, if this is not the Taenia Ccenurus, 

 M. Von Beneden himself reverses his own theory, for in 

 that case all our experiments have been absolutely negative. 

 In fact, if the Tanias met Avith by us cannot be referred to 

 the embryos swallowed, the metamorphosis of the Ccenurus 

 cerebralis into Taenia Ccenurus is wholly erroneous as a fact. 

 There is not escape from this proposition. Our experiments, 

 continued on a lai"ge scale, will before long be laid before the 

 world, and will determine positively whether the transmission 

 of the entozoon of the sheep to the dog, and vice versct, is or 

 is not an actual fact. 



We take this opportunity of informing the Academy that 

 two new experiments recently performed appear to us calcu- 

 lated still more to justify the doubts Ave have expressed. Two 

 dogs, each of which had swalloAved a hundred heads of 

 Ccenurus taken from the same segment, were killed at the end 

 of two months. In one of these dogs the intestine contained 

 two specimens of Tania cucumei^ina, crammed with ova, and 

 about fifty centimeters in length, Avhilst that of the other 

 afforded two of Taenia serrata, one 12 millimetres and the 

 other 120 millimetres long. It is not possible that one and 

 the same Caenurus should give origin to two distinct species. 

 At the same time tlie extreme inequality of length of the two 

 specimens of Taenia serrata indicates that they could not be 

 derived from the same parent ; besides Avhich e\en the larger 

 of them is far too small for it to have been the result of the 

 experiment. 



It has been seen that we have been alarmed only by our 

 success. W^e gathered many more Taenias than we had sown 

 of caenurus heads. This is a cardinal fact. M. Von Beneden 

 himself does not explain this mysterious result. The scolices 

 of the Caenurus only survive the animal infested by it a few 



* That we should not be suspected of partiality, we borrow from a work 

 composed with the greatest care what is said respecting Taenia serrata. 

 It is derived from — 1. CysUcercus imiformis, according to Kuchenmeister, 

 V. Beneden, V. Siebold, Baillct; 2. C. (eimicollis, according to V. Siebold; 

 3. C. cellulosa, according to V. Siebold; 4. Ccenurus cerebralis, according to 

 Haubner ? V. Siebold, V. Beneden, Eschricht, and Leuckart, (Davaine. 

 Eutozoaires, Synopsis, p. 34.) 



