34 MICRO-ORGANISMS AND FERMENTATION. 



ware industry, and contains about 28 to 30 per cent, of hydro- 

 fluosilicic acid (as aluminium fluosilicate) in a clear solution, 

 pale green or yellow in colour, and feebly acid. The protection 

 of walls by means of this preparation depends upon the pores 

 being sealed by the formation of calcium fluoride, alumina, 

 and silica, imparting to the wall a hard and smooth surface. 



Mikrosol appears in commerce as an acid green paste 

 containing about 10 per cent, of copper phenolsulphonate, 

 and smaller amounts of copper sulphate, free sulphuric acid 

 and hydrofluoric acid. It is applied to walls in the form of 

 a 2 to 4 per cent, solution. 



Antinonnin is largely used in order to coat moist walls, 

 and is an excellent preventive of dry-rot, and protects 

 woodwork from worms, etc. It forms a red viscous mass 

 consisting of a potash compound of kresol mixed with glycerine, 

 soap, etc. It is soluble to the extent of 5 per cent, in water. 

 It does not attack either metals or organic substances, and, 

 according to Aubry's investigations, may be applied to advan- 

 tage throughout the brewery, where it cannot come in contact 

 with beer. 



Pyricit, a new preparation, is a white powder soluble in 

 water to form a colourless and odourless solution. According 

 to Wichmann, a 2 per cent, solution forms a very powerful 

 disinfectant, which does not etch or attack either metal, wood, 

 or glass. It may be applied anywhere, inside or outside. 

 It can be kept for a long time without losing its activity. 



Sulphurous acid is one of the oldest antiseptics, and is still 

 frequently used for casks. A piece of linen which has been 

 dipped in molten sulphur is set alight and introduced into 

 the cask. The fumes do not, however, penetrate sufficiently 

 to sterilise badly contaminated casks. Hops and occasionally 

 malt are also treated with burning sulphur. In wine fer- 

 mentation sulphurous acid is sometimes added to the must, 

 to destroy the spontaneous germs before adding pure wine 

 yeasts. Calcium bisulphite forms an energetic reagent, and 

 usually contains about 7 per cent, of sulphurous acid. Diluted 

 from three to six times with water, it forms an admirable 

 agent for the treatment of vats and other apparatus, and is 

 especially deadly to moulds. 



