THE RELATION OF THE LABORATORIAN TO THE 
PRACTITIONER. 
By Leroy F. Thompson, D.V.S., Fort Worth, Tex. 
Continued from May Issue. 
In 1880 Evann described the trypanosome of surra and suc¬ 
ceeded in transmitting the disease by inoculation experiments. 
Following closely upon this discovery was the discovery of the 
cause of malaria by Laveran in 1882, and the causative factor 
was given the name of Plasmodium malaria?. 
Progress was delayed in the study of minute objects like 
bacteria because of lack of proper methods for their isolation, 
identification and observation. Koch and Pasteur were, it is 
said, to be the first to use, successfully, culture media wherein 
pathogenic micro-organisms could be grown. To Koch we are 
also indebted for our knowledge of the solid media which is 
used for the isolation of organisms from mixed cultures, thereby 
relieving the practitioner of doubt as to the real specific cause of 
a given disease. This contribution and its importance can hardly 
be overestimated, for the use of pure cultures lies at the very 
foundation of all modern bacteriologic laboratory investigation. 
To this discovery is due in a large measure the rapid advance 
made during the two decades in the identification of the or¬ 
ganisms producing disease. 
To Weigert we owe the honor and credit for being the first 
man to use the aniline dyes in rendering cells and their struc¬ 
tures more plainly visible under the microscope, but to Koch, 
again, we Owe the credit for their application in bacteriology. 
Since their introduction successive adventures in staining tech¬ 
nique have in every instance been followed by the discovery of 
new organisms related to disease, therefore the microscope, per¬ 
fect technique, liquefiable media and aniline dyes represent the 
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