THE NATURE OF BACTERIA. 21 



may be of advantage, and in preventing their action in places 

 where they would be a detriment. The farm cannot be prop- 

 erly tilled unless the farmer has, in addition to his seed crop, 

 soil and cattle, a stock of the proper kind of bacteria to aid 

 him in preparing the soil and in curing the crops. Farm- 

 ing without the aid of bacteria is an impossibility. Although 

 attempts at a practical application of bacteriological discoveries 

 are numerous, many, indeed most of them, are still somewhat 

 tentative and can hardly be looked upon as having yet reached 

 a position where they can be unhesitatingly recommended to 

 the farmer. Nevertheless, the discoveries already made have, 

 in some respects, revolutionized agricultural processes. The 

 changes in agricultural methods, due to bacteriology, have 

 been largely adopted all over the world ; but they have been 

 generally adopted by farmers, without any knowledge that 

 they are benefiting from bacteriological research. That these 

 practical applications of bacteriology to agricultural processes 

 will increase with the next few years, is certain. We have 

 reached a point where every advanced farmer, who wishes to 

 put himself into a proper condition to make the best use of the 

 means at his disposal, and to profit by discoveries as they are 

 made, must have at least a general knowledge of the funda- 

 mental factors of bacteriology as they are related to agricul- 

 ture. 



WHAT ARE BACTERIA ? 



The term Bacteria is a comparatively recent one. In all the 

 early work which was done with these organisms this word 

 w r as not used as referring to a class of microscopic organisms. 

 Indeed, it was not until about twenty-five years ago that the 

 organisms here included were recognized as forming a group 

 by themselves, being before that time associated with a mis- 

 cellaneous lot of others, including yeasts, molds and some ani- 

 mals. While to-day we recognize Bacteria as forming quite a 

 distinct class of plants, we also recognize that they are closely 



