544 
Preliminary Report on the Broicn Institution. 
It was not until the beginning of May that I was able to 
report that we were in a position to commence our undertaking. 
The nature of the information required, and the conditions 
under which it was requisite to make our investigations, ren- 
dered this delay unavoidable. This will at once become appa- 
rent if it is considered that, as regards pleuro-pneumonia, the 
most important question to be decided is that of the modes by 
which the disease can be communicated. It is admitted on all 
hands that it can be given by a diseased to a healthy animal ; 
but the important question whether or not it can be transmitted 
by means other than that of cohabitation — or, to use the tech- 
nical expression, by mediate contagion — is still disputed. Its 
importance consists in this, that the practical utility of every 
prophylactic measure depends on it. If it can once be shown 
with a certainty beyond the possibility of dispute, that the pre- 
sence of a diseased animal is the sine qua non for the spread of 
pleuro-pneumonia, then it is clear that money spent either on 
disinfection or inoculation is wasted, and that the only pre- 
ventive means to be thought of is either isolation or immediate 
destruction of infected animals. 
This being the problem to be solved, it was necessary, above 
all, that we should begin our work, if I may so express myself, 
with clean hands, that is without even the suspicion of contagion 
about ourselves, our premises, or our animals. Our plans were 
made accordingly. It was determined to begin by purchasing 
a sufficient number of perfectly healthy animals of different 
kinds : viz., two milk-cows, two calves, and four other animals 
of different ages, so selected that' all the individual conditions 
likely to affect liability to infection might be represented. W ith 
the kind assistance of Members of the Veterinary Committee, I 
was able to make these purchases in a most satisfactory manner. 
Three months having elapsed since the arrival of the pur- 
chased animals at the Brown Institution, we feel that we mav 
now regard the immunity of our stock from infection as abso- 
lutely certain, for this period exceeds the highest estimate that 
has been made of the period of incubation. We are now 
therefore, about to commence our experiments. No living sourc( 
of infection shall come near our animals or premises, but w( 
shall try in succession every channel of mediate contagior 
known to us, using in our experiments all that deliberation an( 
caution which the consideration of the importance and diffi 
culty of the inquiry enforces on us. 
As regards foot-and-mouth disease, we have already made 
number of experiments on different animals, but it would b 
premature to make any statement of the results. 
Broicn Institution, Aiujust 1876. 
