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Concluding Report on the Experiments at the 
practically useful ; and (3) to discover a way of inoculating an 
animal without risk. 
With reference to the first point, the opinion generally enter- 
tained is, that a healthy animal may get pleuro-pneumonia 
either directly from a diseased animal, or indirectly by being 
brought into relation with its hide or carcass, or with persons 
or things that have been in contact with its body. Thus, 
Mr. Fleming, the author of the well-known ' Manual of Vete- 
rinary Sanitary Science,' expressed his belief very decidedly in 
1875, that "infection may occur through the medium of forage, 
straw, &c., which have been soiled and breathed upon by 
infected cattle, by the utensils which have been used with them, 
as well as by the persons who have attended to the sick ; " and 
has since that period expressed the same opinion in still stronger 
terms. An opposite view had, however, been guardedly pro- 
mulgated by a very high authority. In the excellent article bv 
Professor Brown on the contagious and infectious diseases of 
animals, which appeared in the tenth volume of the ' Journal,' 
the author said, that " so far as his own observations had enabled 
him to decide, the disease is only communicated by the actual 
contact of a diseased animal with a healthy one, and that it is 
at least exceedingly probable that the mode of communication 
is by the inhalation of the breath of the diseased subject." 
With reference to the second question, that of the utility of 
inoculation, opinions are also, as needs scarcely be said, much 
divided, although the majority are in its favour. One of the 
strongest arguments against it is founded on the acknowledged 
fact, that although inoculation as ordinarily practised produces 
very severe effects, yet these effects are neither the disease 
itself nor any modification of it. It has, indeed, been alleged 
by some authorities that actual lung disease can be generated 
by the insertion under the skin of bits of diseased lung ; but 
this inference, which if it were well established would be of 
great importance, can be shown to be mistaken. The observa- 
tions quoted in support of it are too good to be true. In most 
instances, the time which intervened between the inoculation 
and the appearance of lung disease was far too short ; for we 
have evidence from the pathological inquiries of Professor Yeo, 
as well as from other sources, that the development of the disease 
in the lungs requires a very long time, and usually produces no 
obvious symptoms at all until it breaks out in the acute form in 
which it is ordinarily recognised. Consequently, the appearance 
of symptoms within a week or two after inoculation could not 
reasonably be referred to the operation as their cause ; so that 
we need not hesitate to conclude that the animals in question 
had been previously infected by other means. 
Another statement that has been made with reference to the 
