After describing the specimen, Dr Fock concludes his remarks with a suggestion as to the possibility of introducing tapeworm into the human body by potable water, into which Cysticerci have accidentally found their way. Dr Fock remarks:--“J’ajoute une réflexion par rapport à la provenance des autres tænias, qui jusqu’ici sont introduits par l’usage de la viande non assez cuite ou rôtie, ou saignante; mais, ne se pourrait-il pas que des débris de la chair d’un animal ladre fussent introduits fortuitement dans l’eau, par example, d’un fossé, et que celle-ci employée comme boisson contint des Cysticerques et par ainsi aussi une cause de Tænia? Ce n’est qu’une conjecture que je propose en terminant cet article.” Although I cannot at all agree with Dr Fock in regarding water as a source of infection in the manner he indicates, yet the still more recently expressed opinions of MM. Bertolus and Duchamp, based on experimental researches, render it tolerably certain that Leuckart’s original surmise was correct, and that we must look to freshwater fishes for the larvæ of the broad tapeworm. In the section of this work devoted to the parasites of fishes I shall make particular allusion to the experiences of Dr Bertolus; but as confirming the view of Leuckart I may here observe, that Bertolus has almost proved that the so-called _Ligula nodosa_ infesting the common trout is merely a sexually incomplete example of _Bothriocephalus latus_. The bleak (_Leuciscus alburnus_) shares with other freshwater fishes the privilege of harbouring a species of _Ligula (L. digramma)_; but whether this form bears any genetic relation to our human _Bothriocephalus latus_ can only be determined by actual experiment. If, as Duchamp and others have either indicated or implied, _Ligula alburni_ is a synonym of the bleak’s cestode in question, then it is evident that the sexually mature form of the _Ligula_ of the bleak is the well-known _L. simplicissima_ of many water birds and of a few other avian species. Probably the bleak-eaters of Holland consume many kinds of freshwater fishes, including various species of the salmon and trout family. [Illustration: FIG. 27.--Strobile of _Bothriocephalus cordatus_. After Leuckart.] The symptoms occasioned by _Bothriocephalus latus_ do not differ materially from those produced by other tapeworms. According to Odier, as quoted by Davaine, there is not unfrequently a tumid condition of the abdomen, with sickness, giddiness, and various hysterical phenomena occurring at night. Pain in the region of the heart, palpitations, and faintness are also mentioned.