MINERAL ANTISEPTICS. 109 



ducted by E. CHUARD and M. JACCARD (I.). Apart from the cases 

 already mentioned, this antiseptic is not used in a gaseous form in 

 fermentation industries, since it attacks the metal fittings, irritates 

 the workmen's lungs, &c. It is, however, employed in combination 

 with lime, as calcium bisulphite, CaO . 2 S0 2 . H 2 O = Ca(HS0 3 ) 2 , 

 with which the fermenting tuns, &c., in the brewery are purified. 

 On the basis of his experiments on this point with beer yeasts and 

 film yeasts, H. WILL (I.) recommends an aqueous solution of 

 this salt containing 10 grams of S0 2 per litre. As the com- 

 mercial salt contains 70-75 grams of S0 2 per litre, one part by 

 weight of this liquid must therefore be diluted with six parts 

 of water. 



The suitability of Pictet's solution (liquide Pictet) a mixture 

 of C0 2 and S0 2 (i : i) for disinfecting purposes has been re- 

 ported upon by DE RECHTER and LEGROS (L). 



As a rule, the germicidal power of carbonic acid (carbon di- 

 oxide) is over-estimated by non-professional people. The researches 

 of CARL FRAENKEL (L), confirmed by C. STEINMETZ (L), have 

 shown that this acid has no power at all on certain bacteria, these 

 latter thriving even in an atmosphere of the pure gas. Other 

 species are less able to stand it, and the remaining kinds, though 

 retarded in their development, are killed by it only with great 

 difficulty. The most important literature on the subject has been 

 arranged by P. FRANKLAND and WARD (I.). The above-mentioned 

 fact suffices of itself to destroy the hope that carbonated mineral 

 waters are necessarily devoid of germs (as was assumed by Leone 

 some years back), the researches of P. SIEDLER (I.) having shown 

 that this is not the case. The influence of this acid on the vital 

 activity of yeast and the progress of alcoholic fermentation will be 

 dealt with in the second volume. 



Chlorine, also, is not employed in the gaseous state, but as 

 chloride of lime (calcium hypochlorite). This substance was re- 

 commended by H. WILL (II.) for the disinfection of the sacks 

 made wholly or in part of wool used for filtering off the "cooler 

 sludge " in the brewery. As these bags are rendered unusable by 

 hot water washing, their purification has to be effected by a cold 

 process. That cold washing does not produce the desired effect 

 was proved by Will, who found the sacks to be strongly infected 

 with bacteria and wild yeasts, especially around the stitches, a 

 circumstance sufficient to account for the bad repute in which 

 wort- and beer-droppings are held. Disinfection experiments 

 have, however, shown that these germs can be killed by exposure 

 to the action assisted by careful brushing of a chloride of lime 

 solution containing i per cent, of active chlorine. As good com- 

 mercial chloride of lime yields 30-35 per cent, of chlorine, the 

 solution may be prepared for use by mixing 3-3 J- kilos. (6.6- 

 7.7 Ibs.) of the chloride with i hectolitre (22 gallons) of water 

 i.e. about 5 oz. per gallon, stirring the mixture up frequently, 



