USE OF SULPHUROUS ACID GAS. 139 



My brother, from whose paper I have just quoted, also ascer- 

 tained that when blood which has been treated with carljonic 

 acid is acted on by acids, so as to decompose it, the carl)onic 

 oxide is evolved unaltered, and this occurs in all probalnUty 

 when any blood or meat juice charged with carbonic oxide 

 putrefies. 



The facts I have laid before you constituted, in addition to the 

 experiences of meat-preservers before us, the starting point for 

 experiments more numerous and extensive than had probably 

 ever previously been made in attempts to preserve fresh meat. 



Carbonic oxide gas would preserve the color of our meats, 

 expel the oxygen from the tissues, and act as a neutral gas in 

 the place of air to surround the meat in air-tight vessels. 



We resolved on resorting to the air-pump, and much of my 

 success has been due to the excellence of Bianchi's air-pump, 

 which I imported from Paris. But we knew that the antiseptic 

 action of carbonic oxide was slight, and other agents had to be 

 used. Time will not permit me to relate the experiments with 

 ozone, heavy vapors, — such as chloroform, ether, tetra-chloride 

 of carbon, bi-sulpliide of carbon, bi-chloride of methylene, — or 

 witli carbolic acid, permanganates, chlorine and its compounds, 

 hydro-chloric acid in particular, bin-oxide of nitrogen, sulphites 

 and nitrites. We soon found that the gas which had been most 

 commonly regarded as the meat-preservers' friend would best 

 serve our purpose, and accordingly we soon relied on sulpliurous 

 acid. But every one had failed in times past to use this acid, 

 particularly on a large scale. We had to destroy the germs of 

 putrefaction left in the residuum of air on the meat and on the 

 sides of the preserving cans. The acid gas lias to saturate the 

 meat so as to render it incapable of putrefaction. The water 

 evaporating from the meat had to be absorbed, and above all 

 things the exact measure and weight of the gas to the pound 

 of meat had to be ascertained and used. I fortunately thought 

 of condensing sulphurous acid in charcoal ; and whilst we have 

 at our disposal other means of condensing the same gas, I believe 

 that charcoal saturated with sixty-five times its volume of sul- 

 phurous acid will remain to the end of days the cheapest, most 

 manageable and most universally employed preservative that the 

 meat-preserver can use. It is perhaps bold to predict that which 

 I do, with the greatest confidence, that charcoal and sulphurous 



