4. THE GENERAL CHARACTERS OF MICROORGANISMS 
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 funda- 
mental to the processes of agriculture. 
The agricultural side of bacteriology is, if possible, more impor- 
tant than the pathological side. If the medical student needs to 
know something of these organisms and their relations to disease, 
even more does the agriculturist need to understand their relations 
to his industry. These microdrganisms play such a fundamental 
part in the processes of nature that the life phenomena of animals 
and plants are inextricably bound up in the functions of bacteria, 
and without them life processes must soon cease. The physician, 
in the curing of disease, gains a certain advantage from his knowl- 
edge of bacteria; but the farmer is obliged to make use of these 
agents in a large number of his farming processes; hence, it is a 
matter of necessity that the agriculturist of the future should have 
a practical knowledge of the general phases of bacteriology. The 
solution of the most vital agricultural problems, like that of con- 
tinued soil fertility, involves bacteriology. From beginning to end 
the occupations of the farmer are concerned in the attempt to ob- 
tain the aid of these microédrganisms where they may be of advan- 
tdge, and to prevent their action in places where they would be a 
detriment. The farm cannot be properly tilled unless the farmer 
has, in addition to his seed crop and cattle, a stock of the proper 
kind of bacteria to aid him in preparing the soil and in curing the 
crops. Farming without the aid of bacteria would be an impossibility, 
for the soil would yield no crops. 
The relation of microorganisms to farm life is one of the most 
recent branches of science. Scarce thirty years have elapsed 
since the first steps in this direction were taken, and some of our 
scientists, who are still young, have seen practically the whole 
development of the subject from its starting-point in the early 
eighties. With a science as young as this, it is inevitable that 
