1855.] of Chemistry to the Preservation of Food. 75 



sunk by weights below the level of the fluid. This preparation was 

 made on the 20th of February, 1845.* 



In all these vessels the meat was fresh and sweet. The gly- 

 cerine, however, like the brine, was reddened, indicating the 

 separation of colouring matter, and therefore of iron, from the flesh 

 immersed. The surface of the glycerine in the larger jars was 

 studded with patches of mould. It was therefore inferred that 

 some of the organic constituents of the meat, either singly or in 

 combination, had been also separated ; but that, owing to the 

 impermeability of glycerine by air, tlie decomposition did not take 

 place beneath the surface of the liquid. 



In concluding this part of his subject, Mr. Barlow remarked, that 

 one decomposition was sometimes had recourse to for the purpose 

 of preventing another, as when wood, &c. is preserved by being 

 painted over. The liquid paint is converted, by the action of the 

 atmosphere, into a kind of solid, impermeable, insoluble soap. The 

 stereochrome of Fuchs is another instance of this protective de- 

 composition. There, however, tlie protection is derived from the 

 combination of a portion of the protecting body with a part of 

 that which it is intended to preserve.^ 



C. Organic Substances protected by a Change effected 

 IN THEIR Albuminous Constituents. 



This is accomplished 



(1.) By chemical reagents. 



(2.) By heat and desiccation. 



(1.) Coagulation of albumen, by chemical reagents. 



The preservation of timber, by corrosive sublimate, was fully 

 described by Dr. Faraday, in a Friday evening discourse, in 

 ] 833, on the prevention of dry-rot, when it was proved that this 

 salt formed a stable compound with the albuminous matter of the 

 wood. On March 7, 1845, Mr. Goadby discoursed "on the nature 

 and action of preserving fluids, as applied to animal structure."J 

 This process consisted in the use of a solution of salt, with a small 

 addition of corrosive sublimate. § In illustration of this mode of 

 preservation, Mr. Barlow exhibited specimens of flesh which had 



* The glycerine used in one of these two jars was prepared according to 

 Tilghman's process, by the action of water at a high temperature. Newton's 

 London Journal, Vol. xlv. p. 343. The glycerine contained in the other jar 

 was obtained by the decomposition of a fatty body by steam, as described by 

 George Wilson, Esq. Proceedings of Royal Society, Vol. vii, p. 182. 



t Vide Proceedings of the Royal Institution, April 7, 1854. Vol. I., p. 424. 

 (Rev. J. Barlow on Silica). 



X Vide Athenaum for 1845, p. 272. 



§ Vide Admiralty Manual of Scientific Enquiry, edited by Sir J. Herschel ; 

 article Zoology, by Professor Owen, p. 357 ; and " Directions for Preserving 

 Specimens of Natural History," published by the Smithsonian Institute, Wash- 

 ington, U.S. 1854. 



