DISINFECTION IN PRACTICE. 31 



other difficulties may arise when wild yeast are present, for 

 these, according to Holm and Jorgensen, are stimulated in their 

 development by the presence of hydrofluoric acid in the mash. 



4. Disinfection in Practice. 



It has become clear, within the last few years, that the 

 harmfulness of the germs in air and water has been greatly 

 exaggerated, and that far and away the most important source 

 of danger is to be sought in the growth of foreign organisms 

 in the plant itself. The natural result is that increasing 

 attention is being paid to a rational scheme for disinfecting 

 the plant. As the raw stuffs used in breweries, distilleries, 

 etc., form an admirable nutritive medium for micro-organisms, 

 the distribution of these throughout the plant is much more 

 widespread than usual, and it is often necessary, in addition 

 to mechanical cleansing, to attack them by direct antiseptic 

 means. By determination, on the one hand, of the maximum 

 limit of such poisonous substances that can be allowed, and, 

 on the other hand, of the necessary means to secure the desired 

 object, the practical conditions are established. The con- 

 centration must not exceed what is absolutely necessary. 

 In the use of antiseptics it is essential to follow a recognised 

 plan. A summary disinfection is insufficient if the individual 

 parts present different possibilities for the development of 

 foreign organisms. It is, therefore, necessary from time to 

 time, and that frequently, to overhaul every single point 

 in practice, before being able to say exactly where a particular 

 infection has appeared. At certain points antiseptics must 

 be discarded and mechanical means adopted. This is the 

 case when the infection has penetrated so far into the material 

 that the disinfectant is no longer able to attack it. This may 

 occur in the great majority of wooden vessels as they are 

 usually prepared. 



As many micro-organisms form slime, and may produce 

 thick deposits when allowed an undisturbed development, it 

 is often necessary to use a solvent of the slime before proceeding 

 to actual disinfection, if the germicidal substance is not capable 

 of completely dissolving the slime. 



