214 BIOLOGY OF SPECIALIZED GROUPS 



tion is a distinct anaerobic process. Butyric acid is also 

 formed by the decomposition of casein and fats, in addition 

 to milk sugar. 



In addition to the various organic acids which may be 

 produced in milk some of the higher alcohols may be 

 formed. 



Mucilaginous fermentation, which has been discussed pre- 

 viously as occurring in milk, give it a thick, slimy consistency. 

 The bacteria in milk and the various dairy products such as 

 cheese, butter, etc., will receive more detailed consideration 

 in a subsequent chapter. 



Bacterial Fermentations in the Arts. This interesting 

 subject can be only briefly considered. Some fermentive 

 processes are of great economic importance, while others 

 are decidedly antagonistic to certain industries. 



In the " retting " of flax (linen), jute, hemp and cocoanut 

 fiber, fermentations, similar in a measure to putrefactive 

 processes, are important in the softening of the cellulose 

 walls of the plants so that the fibers may be separated. 



In the preparation of indigo from the indigo plant (Indigo- 

 fera tinctoria) and in the curing of hides and tobacco, bac- 

 terial enzymes are important adjuncts to the processes. 

 Bacterial enzymes are also of commercial importance, as 

 before stated, in the preparation of vinegar (acetic acid), 

 butyric and lactic acids, and in many dairy processes, such 

 as cream ripening, cheese and butter making. 



Bacterial fermentive enzymes are responsible for the un- 



