PREVENTION. 217 



II may be coagulated and preserved from putrescence by alcoliol, oil 

 of turpentine, and some other volatile oils. Creosote possesses a most 

 decided power of coagulation ; a very minute portion in vinegar being 

 sufficient to preserve meat that has been soaked in it, to which it also 

 communicates a smoky flavor. The process of smoking meat owes its 

 efficacy in a great degree to the action of creosote, which always accom- 

 panies the smoke from wood. Water takes up but Ij per cent, of this 

 oil, but alcohol unites with it in every proportion. 



The earthy and metallic salts possess the same property, and are 

 most of them powerful antiseptics. They act by separating albumen 

 from its watery solutions, and forming with it insoluble compounds. 



The alkaline salts are not quite as efficacious. Common salt has 

 been used in every age and country for the preservation of meats. Alum 

 is the most energetic of the earthy salts, and is three times as powerful 

 as the muriate of soda. 



The metallic salts are much more powerful than the earthy, and form 

 more intimate combinations. A solution containing^ the one-five-hun- 

 dredth part of nitrate of silver, is said to be capable of preserving ani- 

 mal matters from corruption. Corrosive sublimate has been extensively 

 used in the preparation of specimens for museums, and experience has 

 fully proved its entire adaptation to this purpose. Similar properties are 

 possessed by arsenic. 



We have now explained only one of the general principles upon 

 which the decomposition of animal and vegetable substances may be 

 prevented, viz. by the chemical change of the azotised substances ; three 

 other modes yet remain to be described, but as we have almost attained 

 the limit of our article, their explanation must be postponed. 



In reflecting upon the various substances which have been and may 

 be \ised to arrest the decomposition of animal and vegetable tissues, a 

 wide field of the most important investigation is opened to our view. — 

 How important to society, we might say to every individual in society, 

 is the question. What is the best mode of preserving animal and vegeta- 

 ble substances from decay ? In the art of tanning we see an illustration 

 of its importance. What could we do without leather ? Large quantities 

 of food which might have afibrdod wholesome nutriment to man and 

 other animals, become corrupt and poisonous — the timbers used in con- 

 struction, the posts of fences, our houses and ships, are all liable to ra- 

 pid decay, and produce an annual loss of millions. It is by no means 

 certain that a cheap and efficacious mode of remedying the evil cannot 

 be discovered. We know of some that have been fully tested, and have 

 been found to'answer. Corrosive sublimate in the proportion of 1 pound 

 28 



