S58 



with the formation of a cottony substance around its gills, and on 

 other parts of its body. In a specimen put into his possession by 

 Mr Goodsir, the authoi- found that the cottony substance presented 

 under the microscope both a cellular and a non-cellular structure. 

 The former consisted of long tubes divided into elongated cells, at 

 the proximal end of which there was a transparent vesicle or nucleus 

 about a 100th of a millimetre in diameter. Some cells were filled 

 with a granular matter ; others were empty, as if they had discharged 

 their contents. Besides this structure, there were also long fila- 

 ments, about a 600th of a millimetre in diameter, which sprung 

 from the tubes, and seemed to consist of a diaphanous sheath, and a 

 solid transparent matter. This structure, as in the two previous 

 instances, sprung from a finely granular amorphous mass. 



The author next gave a condensed view of the history of his sub- 

 ject, describing more especially the observations and discoveries of 

 Bassi, Audouin, and Johanys relative to the Muscardine, or fungous 

 disease, of silk-worms, — those of Hannover and Stilling, on the Con- 

 fervsG which infest reptiles,— those of Ehrenberg, Goodsir, and Coo- 

 per, on the mycodermatous vegetables of fishes, — those of Owen and 

 Deslongchamps, on birds, — and those of Schoenlein, Fuchs, and 

 Langenbeck, Gruby, and others, on man. And from all the facts 

 hitherto collected on the subject, he inferred, that the vegetations in 

 question are not the cause, but the result of disease in animals, — 

 that they grow on unorganized matters, apparently albuminous or 

 tubercular in nature, which are effused into the healthy textures, — 

 that they occur only in animals previously weakened by circum- 

 stances inducing imperfect nutrition, — and that their growth is to be 

 counteracted partly by invigorating the body and partly by local 

 applications hostile to vegetable life. 



The paper was accompanied with drawings of the appearances 

 described. 



2. On the Action of Water on Lead. By Dr Christison. 



The author, after briefly stating the results of his Experimental 

 Inquiries, published on this subject in 1829, proceeded to describe 

 two instances which had recently come under his notice, illustrative 

 of the solvent action of certain terrestrial waters on lead, and of the 

 danger of using this metal for conducting water in pipes, unless with 

 a due regard to the circumstances which promote or prevent its cor- 

 roding property. In one instance, the water of a spring, conveyed 



