MEDIATE CONTAGION IN PLEURO-PNEUMONIA. 
63 
ORIGINAL ARTICLES. 
MEDIATE CONTAGION IN PLEURO-PNEUMONIA, 
By D. E. Salmon, P.V.M., Chief of the Bureau of Animal Industy. 
(Read at the Meeting of the U. S. V. M. Association.) 
-in the fall of 1886 Dr. Gadsden was in Illinois and preacdied 
the gospel of mediate contagion with such enthusiasm that he 
converted the State Live Stock Commission, and persuaded them 
to force the issue with the Bureau of Animal Industry, as to 
whether the disinfection of premises where diseased cattle had 
been was a necessary precaution against this contagion. A con¬ 
troversy was started in this way which is not yet finished. The 
doctor and his disciples have carried their case into the daily and 
weekly newspapers, and seem to consider it a most remarkable 
feat when they have succeeded in convincing people who under 
no circumstances have an opportunity of hearing the other side 
of the case, and who from total lack of scientific training would 
be incapable of reaching a logical conclusion if they had all the 
facts before them. The propagation of these erratic views, 
which under no circumstances can make the measures adopted 
against pleuro-pneumonia more thorough or hasten the time when 
the disease will be eradicated, have done much to cause distrust 
of veterinary counsel and to impede the progress of the work. 
Some of you will doubtless remember that at the meeting of 
this Association at Philadelphia about a year ago, I asked for an 
expression of opinion on the theory of mediate contagion and on 
the necessity for disinfection. If I remember correctly, there 
was no voice raised at that time in support of the theory that 
pleuro-pneumonia can only be propagated by contact with the 
living diseased animal, and there was a unanimity of opinion in 
favor of disinfection. # 
