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produced in a state of vapour by pouring sulphuric acid on 

 nitrate of soda or potash, placed on a heated plate, has been 

 successfully employed in the wards of hospitals, &c. As a 

 disinfectant it acts precisely in the same manner as chlorine, 

 though probably with less energy. Nitrate of lead has also 

 been recommended as a disinfectant for fluids, and, in con- 

 sequence of its oxydizing tendencies, would probably be a 

 very effective agent in destroying matters ready formed in 

 the mixture, although I very much question whether it would 

 arrest the progress of decomposition entirely. The expense, 

 however, of procuring this agent will always be a prohibition 

 to its general use. Any of these may be employed success- 

 fully, with very little precaution.* 



There are other substances, however, whose mode of 

 action, though not so well understood, is nevertheless of 

 great importance, from the certainty with which they arrest 

 the process of decomposition when mixed with organic fluids. 

 Of this class are the various kinds of antiseptics, such as 

 volatile oils, alcohol, coal and wood tar, and probably all 

 their constituents, acetic acid, wood smoke, common salt, 

 &c. The action of these matters is best seen when added 

 to fermenting yeast or wort. If a single drop of creosote, 

 or a small quantity of an essential oil, be added to yeast, it 

 will immediately put a stop to the change it is undergoing, 

 and prevent its communicating decomposition to a solution 

 of sugar. The same thing takes place when these substances 

 are added to flesh, or any nitrogenous organic compound. 

 The common process of curing meat by smoking it with 

 burning wood, in which creosote, &c., is generated, and of 

 preserving animal specimens in alcohol or volatile oils, are 

 instances of their preservative properties ; and although this 



* Since writing the above, I have ascertained that good chloride of lime 

 contains four times the amount of available chlorine, and consequently will 

 possess four times the disinfecting power, of Ellerman's fluid. 



