PART II 
DIAGNOSIS 
It is essential that one should appreciate the close relation- 
ship of the methods already studied to those that must be fol- 
lowed in practical diagnostic work. This means that in the 
diagnosis of various infections the practitioner must employ, 
for the determination or identification of the etiological agents, 
methods like or similar to those used in laboratory instruction. 
Many of these methods can be actually employed in the field, 
while in other cases it is necessary to send the material to a 
laboratory for examination. When it is necessary to forward 
tissues to a laboratory it is essential that they should be sent in 
such a manner that when they reach the examiner they will be 
in a condition suitable for making the required examinations. 
The infectious diseases which are commonly encountered in 
this latitude are largely of bacterial origin. It sometimes 
happens that diseases due to fungi and protozoa are met with. 
In certain cases a histological study of the tissues is necessary. 
In the following sections somewhat specific methods are given 
for the diagnosis of the more common infectious diseases 
encountered by the veterinarian. 
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