

MICROORGANISMS AND FARM LIFE. 3 



disease. Their relation to the medical profession was soon 

 recognized, and more or less extended courses in bacteriology have 

 rapidly made their appearance in medical schools. Health boards 

 and sanitary officers have recognized that their primary duty is 

 to deal with bacteria; and most of the regulations for the preserva- 

 tion of the public health have been directed toward the destruction 

 or control of these organisms. 



As more information has accumulated during the last twenty 

 years or so, it has become evident that microorganisms, including 

 bacteria, do not deserve all the ill repute that they have acquired. 

 It has been learned that there are hundreds and even thousands of 

 kinds of bacteria, and that, while certain species are the cause of 

 disease, others are harmless, some are beneficial in the body, and 

 many perform functions of the highest significance and value. 

 Although the disease side of the bacteria story was the first to be 

 studied, it is only a small part of the subject. Among the many 

 hundred kinds of bacteria known, only a few, less than two score, 

 are as yet definitely known to have any power of causing disease 

 in man. As bacteriologists have widened their views and looked 

 outside of the human body, they have found that these organ- 

 isms are not only excessively abundant in nature, but have 

 relations to the phenomena of living things which were wholly 

 unsuspected. Within the last twenty years a larger and larger 

 amount of attention has been directed to the part played in nature 

 by microorganisms which are never parasitic and have no relations 

 to human disease. As a result there has developed a new branch of 

 bacteriology which deals with phenomena wholly separate from 

 disease. 



Relation to Agriculture. In particular it has been shown 

 that bacteria are related to agriculture. Not only is it true that 

 they are the cause of certain animal and plant diseases with which 

 the farmer has to contend, but it is becoming manifest that they are 

 intimately associated with many normal processes which are going 

 on in the soil, water, and elsewhere, and that they are fundamental 

 to the processes of agriculture. 



The agricultural side of bacteriology is, if possible, more impor- 



