90 SCIENCE AND PRACTICE OF DAIRYING. 



regulation of a large number of fermentation processes. Since the 

 technique of dairying is, as a matter of fact, dependent to a very 

 large extent on ferments, which affect alike the distribution of milk 

 for direct consumption or its utilization for dairy products, the neces- 

 sity exists for everyone who takes an interest, either theoretically 

 or practically, in the domain of dairying, to make himself familiar 

 to a certain extent with bacteriology. It is especially necessary for 

 the directors of agricultural experimental stations and laboratories to 

 make themselves familiar with the science of bacteriology generally, 

 and with the methods and details of the processes of investigation. 

 The gradual abolition of the uncertainty surrounding dairy manu- 

 factures is the present important duty which lies before us, and its 

 solution can only be effected by bacteriology. For this reason 

 bacteriological research is of the highest importance to dairying, 

 and it is this consideration which justifies our devoting a short 

 section to its discussion. 



37. The Lower Fungi. Although microscopical organisms, espe- 

 cially bacteria, were discovered in the year 1675 by the Dutchman 

 Leeuwenhoek, our knowledge of them was no further advanced. 

 No idea could then be formed of their enormous distribution in the 

 air, water, or soil, nor was it dreamt that they performed such an 

 important role with regard to human life. Indeed, they were long 

 regarded as harmless, and as performing no functions in terres- 

 trial economy. Nevertheless it was observed that they occurred in 

 large numbers in all fermenting and decomposing bodies. This 

 phenomenon could be explained in two ways. The bacteria and 

 the other low forms of fungoid life could be the exciting cause of 

 fermentation and putrefaction, or, on the other hand, their presence 

 might have nothing directly to do with these processes, and they 

 might only be found in large numbers on such bodies because the 

 fermenting and putrefying bodies provided suitable conditions for 

 their development. In opposition to the vitalists, the supporters 

 of the first-mentioned view, it was sought to trace fermentation 

 and putrefaction to purely chemical and mechanical causes, espe- 

 cially to the oxygen in the atmosphere. At the end of the sixth 

 decade of the present century a very interesting discussion took 

 place between Justus von Liebig, who supported the chemico- 

 mechanical theory of fermentation, and the vitalist, Pasteur. What 

 had already been asserted by Spallanzani, Cagnard-Latour, Schwann, 

 and others, with regard to the process of putrefaction, was soon 



