186 



still, in Scotland it is rare. It occurs rarely in Vienna, on the 

 authority of Bremser ; but Rudolphi says, that every session a few 

 cases occur in the dissecting-rooms of Berlin. The points of its 

 anatomy, to which the author chiefly directed his attention, was, 

 1st, The structure of the enclosing cyst or capsule, which he still 

 maintains to be an essential part of the worm, although not mecha- 

 nically connected with it ; and offers it as his decided opinion, that 

 neither in the cysticercus, nor in the vibrio, does the enveloping 

 cyst seem to be formed out of the surrounding cellular tissue. 2d, 

 The anatomy of the disk of hooks, whose sole use anatomists have 

 hitherto supposed to be to enable the parasite to attach itself to the 

 surrounding textures of the animal on which, and by which it lives : 

 — to the so-assigned use he finds an insurmountable objection if it 

 really be, as most imagine, that the cyst or capsule is closed on all 

 sides ; and he further has described certain rounded or oval bodies, 

 resembling globules, situated near the base of each hook, which he 

 conjectures may be young cysticerci, which view, should it prove 

 ultimately correct, would shew that the disk of hooks is more par- 

 ticularly connected with the generative system than with the diges- 

 tive organs. 



3. Examination of certain Objections to the Theory of Iso- 

 morphism. By Henry Madden, Esq. 



The object of this paper was the refutation of certain arguments 

 brought forward against the doctrine of Isomorphism, more espe- 

 cially by those who allow the existence of an approach to, although 

 they deny absolute identity of, form. 



The author sets out by shewing, that most of the arguments are 

 deduced from observations made on crystallized minerals ; and he 

 then proceeds to state the many important circumstances which 

 tend to influence the form of these bodies, but which can be easily 

 avoided in those salts which admit of being formed artificially ; 

 such are, the intense temperature to which they are subjected, the 

 pressure of surrounding matter, the admixture of foreign bodies, &c. 

 each and all of which he proves to exert a powerful influence over the 

 forms of crystals. From these facts, he concludes that the law of Iso- 

 morphism cannot be considered as invalidated byanyslight differences 

 found to exist in minerals, unless it could be proved that the crys- 

 tals in question were formed under precisely similar circumstances. 

 The author next proceeds to give an account of the results of his 

 own experiments (when competing for the Hope prize), in so far 



I 



