88 
DR. GADSDEN. 
MEDIATE CONTAGION. 
Answer by Dr. Gadsden. 
A Letter read before the United States Veterinary Medical Association. 
My Dear Doctor: 
Your kind favor of the 4th inst., containing an invitation to 
attend and address the annual meeting of the United States 
Veterinary Medical Association, on the subject of “ Mediate 
Contagion ” in contagious pleuro-pneumonia, was received at my 
house during my absence from the city, and was forwarded to 
Longport, and failing to reach me there was returned to Phila¬ 
delphia, where I received it yesterday. I regret very much that 
the invitation came to me so late that I will be prevented from 
accepting it by other engagements which I had made before re¬ 
ceiving it, and the shortness of the time will prevent my writing 
anything on the subject further than to reiterate the views ex¬ 
pressed in my former paper, a copy of which I will mail you on 
my return to the city to-morrow, together with any new facts I 
may be able to gather in the brief time before your meeting. 
It was a long time before some of our professional brethren 
could be convinced of the truth of the theory which I held, that 
the disease was spread by the chronic or so-called recovered cases, 
but even our friend Dr. Salmon I think will now admit, after 
the careful experiments he has made, that this theory is correct. 
And I feel assured that it is but a question of time when he and 
the others who now hold to the contrary opinion will be con¬ 
vinced, if they will devote the same care to experimenting, that 
the disease can only be communicated by contact with the living 
diseased animal. Now by contact I don’t mean an actual rub¬ 
bing together of the diseased and healthy animals, as would seem 
to be implied by Prof. Law in his rejoinder, but their confine¬ 
ment together in the same building or small enclosure, where the 
germs exhaled in the breath of the diseased animal can be in¬ 
haled by the healthy ones. For I am thoroughly convinced that 
after the death of the animal any germs that may have been con¬ 
tained in its carcass lose vitality, and the power to infect the 
