MICROORGANISMS AND FARM LIFE 3 
It was quite early suggested, and soon demonstrated, that these 
little plants have the power of producing certain dreaded diseases, 
and the reputation which they thus obtained still clings to them. 
The very word bacteria, or germs, has become, in the minds of some, 
almost synonymous with 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 regula- 
tions for the preservation of the public health have been directed 
toward the destruction or control of these organisms. 
As more information has accumulated during the last twenty- 
five years or so, it has become evident that microdrganisms, includ- 
ing 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 
organisms are not only excessively abundant in nature, but have 
relations to the phenomena of living things which were wholly 
unsuspected. Within the last twenty-five years a larger and larger 
amount of attention has been directed to the part played in nature 
by microdrganisms 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 
