DESTRUCTION OF MICRO-ORGANISMS. 105 



the common beer yeasts, and are not able alone to cause the fermen- 

 tation of milk-sugar. This can only take place after the milk-sugar 

 has been dehydrated by the bacteria present in the kephir grains. 

 These bacteria act in different ways, some being able to induce 

 lactic fermentation, others to dehydrate the milk-sugar in presence 

 of certain yeasts, and others to partly peptonize the caseous matter. 



45. Destruction of Micro-organisms. In conclusion we may say 

 a word or two on the methods of destroying the microscopic enemies 

 of dairying, and the methods of effecting complete cleansing of milk- 

 vessels and the disinfecting of dairy rooms. For cleansing of vessels 

 of all kinds, different materials may be used according to their 

 nature, such as steaming under pressure, treating with hot strong 

 alkali solutions, preferably boiling soda solutions, or solutions in 

 which burnt lime has been dissolved. The disinfection of rooms or 

 spaces can be effected by covering the walls and ceilings with freshly 

 prepared milk of lime, or with a solution consisting of calcium 

 sulphate, and sprinkling the floor with an alkaline solution. Bad 

 flooring should be thoroughly repaired or entirely renewed. In 

 order to clean the hands one should wash them over with black 

 soap or a solution of creasote. Poisonous disinfectants, such as 

 mercuric chloride (corrosive sublimate) ought not to be used in 

 dairying. 



46. The Practical Application of Bacteriology. From the above 

 statements it may be safely asserted that dairying has already much 

 for which to thank bacteriological investigation. Bacteriology has 

 drawn our attention to the existence of a large number of well 

 ascertained and valuable facts that have new and highly important 

 and practical bearings on dairy practice. It has shown that dairying 

 must reckon in practice with small, and, so far as the naked eye is 

 concerned, invisible friends and foes. It has further taught the 

 desirability of sterilizing and Pasteurizing milk and its liquid by- 

 products, and in this way has conferred great benefits benefits 

 which are not half sufficiently recognized by showing the import- 

 ance of such treatment, not merely from the physiological and 

 sanitary point of view, but also in the technical interests of dairy 

 manufactures. It has further discovered the true causes of many 

 troublesome disturbances or diseases of milk, and has already pointed 

 the way, in at least a large degree, to their cure. Finally, it has 

 opened a prospect of the possibility of successfully combating tuber- 

 culosis in cattle. 



