24 
.TAMES LAW. 
only invasion of the lnng tissue is at the root of both lungs in an 
area about half the size of a hen’s egg, where there is undoubted 
contagious pleuro-pneumonia, the inter-lobular exudation being 
directly continuous with that in the superior mediastinum. The 
changes in the mediastinum are of much longer standing than 
those in the lungs, and certainly point to the fact that we may 
have what is termed pleuro-pneumonia contagiosa without any lung 
lesions. 
LUNG PLAGUE BY MEDIATE CONTAGION, 
By Prof. James Law. 
I am always glad to read the earnest utterances of my friend 
and co-worker, Dr. J. W. Gadsden, and I need not say that I 
sympathize with him in the omission of his paper at the Consoli¬ 
dated Cattle Growers’ Convention. Congratulation is due him, 
however, in that he has now had the privilege of placing it before 
a no less appreciative audience, and one better able to canvas 'its 
merits. That there is a substratum of truth in his position no 
one acquainted with the lung plague will deny; that the virus is 
not so tenacious of life as that of small pox, cow pox, glanders 
and tuberculosis, for example, will be readily conceded; but 
the extreme position taken in his paper, “ that the contagion 
can only be communicated by contact with the living diseased 
animal,” very few indeed can be brought to admit. 
To begin with, I venture to assert, and without fear of suc¬ 
cessful contradiction, that Dr. Gadsden himself does not believe 
this. He has become so impressed with the perishable nature of 
the lung plague virus, that he has, perhaps unconsciously, stated 
his case much more strongly than he meant to. No one of the 
opponents of mediate contagion hold that “ actual contact with 
the living diseased animal ” is essential to the propagation of 
the disease. It is well to demonstrate this before proceeding 
to consider the position which I believe he is willing to contend 
for : “ that the virus is so easily destroyed that it is unnecessary 
to disinfect a building where cases of lung plague have been .” 
To return then to the question of “ actual contact Dr. 
