BOTHRIOCEPHALUS LATUS. 295 



was no need for any intermediate bearer ; for, says lie, in effect, I 

 have succeeded in rearing young Botliriocepliali, directly from 

 embryos administered to dogs. That Knoch has succeeded in 

 procuring young sexaaUy immature Bothriocephali from dogs, no 

 one need entertain any doubt; but to afl&rm that these were 

 developed as the result of his administrations is quite another 

 matter. He appears to have been unaware of the circumstance 

 that examples of this worm are occasionally found in the dog. On 

 this point Leuckart remarks, that " according to Pallas the B. latus 

 is not rare in the dogs of Southern Eussia, whilst Von Siebold 

 says he has received it also from a dog in Pomerania.* Linneus 

 had made similar communications previously, but he supposed that 

 the Swedish dog-tapeworm was not referable to Taenia lata but to 

 Taenia vulgaris ; the latter being, possibly, identical with our B. 

 cordatus, which, as we shall see, is more frequently found in the 

 dog than in man." Notwithstanding Knoch's conclusions, there- 

 fore, we cannot bring ourselves to beHeve in the notion that the 

 Bothriocephalus latus is capable of development without the aid of the 

 ordinary intermediate host. If one may be permitted to hazard a 

 conjecture as to the nature of this host, I should, on independent 

 grounds, look to certain species of fish, and, especially, as Leuckart 

 also has suggested, to the salmon and trout family. Kiichenmeister's 

 idea that the scolex or hydatid condition of this cestode may be 

 found in certain species of Limax is not all convincing ; yet, it is 

 not impossible that they may occur in the bodies of fresh- water 

 molluscs or other aquatic animals belonging to the articulate 

 class. I repeat, however, my strong persuasion, that people infest 

 themselves with this parasite by eating imperfectly cooked fish, in 

 which the Bothriocephalus larvae have taken up their temporary 

 abode. In this connection, moreover, it is not uninteresting to 



* Professor J. B. Simonds, of the London Veterinary College, informed me, some 

 time ago, that he had obtained a well-developed example of Bothriocephalvs latus from 

 an English dog ; and I have since had an opportunity of examining the specimen, which 

 is preserved in the College Museum. 



