THE PREPARATION OF FARM PRODUCTS. 289 



which he sets aside for the purpose will contain some of the 

 acetic acid bacteria and that in course of time he will obtain 

 vinegar. Whether he gets the advantage of all the alcohol, or 

 loses half of it, does not matter much to him. Even if several 

 barrels should not produce a proper quality of vinegar it would 

 not be of much importance. Sometimes he finds that his 

 vinegar is stronger than at other times, and sometimes he finds 

 that its taste is much inferior to the ordinary grade of vinegar. 

 Perhaps this raises in his mind a temporary question as to the 

 reason for the differences. But he never pursues the subject 

 further. The reason is doubtless, in all cases, the differences 

 in the condition of the acetic acid bacteria growing in his cider ; 

 for whether he is aware of it or not, his vinegar is prepared 

 for him by the activity of one or more species of the acetic 

 bacteria which he has ever at his command. 



II. THE FERMENTATION AND CURING OF TOBACCO. 



It is unnecessary to emphasize the great significance of the 

 tobacco crop for the agricultural industry, or the importance 

 of a thorough understanding of the proper methods for making 

 the finished product. Tobacco is a crop the value of which is 

 wholly dependent upon the success of its curing and final 

 preparation for market. The green crop is valueless and many 

 a crop is ruined in the curing. That the curing of tobacco is 

 primarily a fermentative process is an undisputed fact. Until 

 recently it has been believed that the fermentation which takes 

 place in the curing is due to the growth of bacteria. In recent 

 years, however, it has become doubtful whether bacteria play 

 the important part in the process that was believed a few years 

 ago, inasmuch as it has been shown that certain enzymes, pro- 

 duced by the tobacco leaves themselves, are the chief agents 

 in the fermentation. It is still insisted by some bacteriologists 

 that, although these enzymes are important agents, bacteria 

 are after all factors of the utmost importance in the normal 



