PREFATORY NOTE 
It has been found desirable to provide the student, just be- 
ginning the study of bacteriology, with a somewhat detailed 
outline of the work to be done at each laboratory session. The 
selecting of the particular things to be done and the choosing 
of methods to be followed are difficult tasks. The assigning of 
directions for doing work under assumed conditions must neces- 
sarily partake of the empirical, and often fail. It is evident, 
however, that practical bacteriology and protozodlogy must, if 
successfully taught, be cast in a somewhat definite form in 
order that the student may come to a knowledge of the funda- 
mental principles underlying the subject in its twofold capacity 
—— that of a pure science and of a useful art. 
These exercises are intended either to serve simply as a 
guide through an introductory laboratory course preparatory to 
independent research work, or to form the basis for the appli- 
cation of the principles of microbiology in the practice of 
veterinary medicine. They aim to impart a definite knowl- 
edge of a few important species of microorganisms and a 
working knowledge of certain of the more essential methods. 
Following the regular laboratory exercises are directions for 
the diagnosis of several specific diseases. These are based 
largely on the instruction given in the previous exercises. 
THE AUTHORS 
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