272 BACTERIOLOGICAL AND ENZYME CHEMISTRY 



vegetable albumins, forming amino acids, etc. ; these actions, 

 being purely enzymic, will go on after the cell is dead. Accord- 

 ing to Russell, bacteria are also present, yet they are not the 

 chief agents in the decomposition, though they probably 

 attack the softer cellulose, producing humus and some fatty 

 acids ; they also carry to a further stage the decomposition 

 of certain of the nitrogen compounds. These changes are 

 summarised in the table on the opposite page, which may 

 be taken as a typical statement of the changes occurring 

 during the ensilage of fodder. In this particular case, maize 

 was taken as the subject of experiment, and air was excluded 

 as far as possible. With other materials, e.g. exhausted beet 

 from sugar factories, etc., a greater proportion of acid may 

 be obtained, in which case sour fodder is produced. It may 

 even be possible to inoculate silos with selected ferments, 

 in order to obtain the best results. Incidentally it may be 

 mentioned that the ' sauerkraut ' of the German restaurant 

 is produced by an analogous species of fermentation. 



The Bacteriological Chemistry of Dairy Products. 



Starting from milk, as raw material, a great variety of pro- 

 ducts are obtained in modern dairy practice : cream of different 

 flavours, butter both sweet and sour, cheeses in great variety, 

 both soft and hard. These different products are not in general 

 all produced in one dairy or even in one district ; rather indeed 

 are we accustomed to differentiate them according to the place 

 of manufacture : thus Dutch cheese and Swiss cheese differ 

 from those produced in England, and the different varieties of 

 English cheese, as is well known, were at one time derived 

 from different districts. The ultimate reason for this is to be 

 found in the bacteriological conditions which long practice has 

 established in various dairying centres. Modern advances in 

 dairy practice seek to render it possible to produce any kind of 

 dairy product at will, at any centre. 



