MINERAL ANTISEPTICS 



With regard to the deadening of wine-must by sulphurous acid, referred to 

 in n, mention may be made of the discovery of this observer that 25 c.c. of 

 SO., per litre sufficed not only to hinder the inception of fermentation in wine- 

 must, but also to bring it to a standstill when already in progress. The presence 

 of a small quantity by itself inert of another mineral acid was found to 

 increase the power of the sulphurous acid in a remarkable degree. The subse- 

 quent fate of this latter in sulphured wine varies : a small portion combines with 

 the aldehydes, a little (often merely a trace) of which is always present, to form 

 aldehyde-sulphurous acid, a compound of agreeable odour, but the bulk is converted 

 into sulphuric acid, and is then found as potassium sulphate. Several experi- 

 ments in this connection have been conducted 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, ifcc. It is, however, employed in combination with lime, as 

 calcium bisulphite, Ca0.2SO 2 .H. ) = Ca(HSO 3 ) 2 , with which the fermenting 

 tuns, tfcc., 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 SO 2 per litre. As the commercial 

 salt contains 70-75 grams of SO., 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 (JO 2 and 

 SO, (i : i) for disinfecting purposes has been i-eported upon by DE RECHTER 

 and LEGROS (I.). 



As a rule, the gsrmicidal power of carbonic acid (carbon dioxide) is over- 

 estimated by non-professional people. The researches of CARL FRAENKEL (I.), 

 confirmed by C. STEINMETZ (I.), 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 shewn 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 recommended 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 



