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LEROY F. THOMPSON. 
most important factors to the laboratory man in the development 
of the science of bacteriology. 
In 1875 the credit is due Lister for using the first antiseptic 
precautions, though crudely, but which opened up the field for 
progressive and scientific surgery. 
The influence maintained by the laboratorian to-day in the 
development of veterinary medicine really began with Virchow, 
who nearly a century ago established the cellular theory from 
which has developed cellular physiology 7 and the detail of cellular 
action of various drugs. So the theory of ancient history known 
as the humor theorv, which was the belief at that time—that 
the bodv was made in the form of a sack or bottle and contained 
but three fluids or humors—was successfully explained by this 
remarkable discovery. 
Secondly, I will endeavor to bring out only a few points in 
immunity to further show the need for closer relationship be¬ 
tween the practitioner and laboratorian. Further, to show the 
practitioner just how much he is indebted to the laboratorian for 
his zealous work in this branch of knowledge and science in the 
successful treatment and eradication of disease. 
Immunity is a term used to express relative resistance to 
disease. It is defined bv Ricketts as follows: “ Bv immunity 
we understand that condition in which an individual or species 
of animal exhibits unusual or complete resistance to an infection 
for which other individuals or other species show a greater or 
lesser degree of susceptibility.” It is but natural, then, for the 
converse of immunity to be susceptibility or lack of resistance. 
It is therefore easily noted the broadness of this subject and 
hence the need for me to deal with it as briefly as possible in 
order that a part of it may be incorporated within the scope of 
this paper. 
There is a great deal of credit due to the laboratorian for his 
contribution to the medical world of the various biologic products 
which are of so great a value to the profession and the world at. 
large in the prevention and treatment of disease. The time has 
come when prophylactic science in the eradication of disease is 
