INOCULATION FOR PLEURO-PNEUMONIA. 673 
In 1757-8 another of these epizootic diseases reached our 
shores, and many of our cattle died. Dr. Layard described it as 
putrid, malignant, and inflammatory fever, attacking the Ox 
tribe alone, and producing ulcers in the mucous membranes, 
and external parts of the body. After this, we have no 
account of any similar outbreak, until the year 1839, when 
Eczema made its appearance. This was quickly followed by 
Pleuro-pneumonia , and this again by the Small-pox of Sheep. 
The two former undoubtedly belong to the epidemic class, 
for, like cholera, their appearance here cannot be traced to 
any known cause: but the latter clearly arose from the im¬ 
portation of some infected sheep. Some of these maladies 
are both contagious and infectious, in the ordinary acceptance 
of these terms, while it is a matter of great doubt whether 
others possess either of these properties. Many of the con¬ 
tagious class can be communicated from animal to animal by 
inoculation, and even safely so, the inoculated proving, as a 
rule, a milder disease than the natural. This fact was long 
since established in medicine; and we find that Dr. Layard 
was a strong advocate for the inoculation of cattle, in 1757, 
as a preventive of the malignant and ulcerative disease which 
then prevailed; it being a singular feature in many of these 
contagious diseases, that they rarely attack the same animal 
a second time. At this moment the inoculation of cattle, to 
prevent pleuro-pneumonia, is exciting the liveliest attention 
of many of the governments of Europe. Already France, 
Holland, Belgium, and Prussia, have appointed commissions 
of scientific men to inquire into the success and value of the 
practice. 
The plan seems to have originated with Dr. Willems, of 
Hasselt, the chief town of the province of Limbourg, in 
Belgium. The commissions, above referred to, have each 
visited Hasselt and other places where inoculation has been 
adopted, to institute inquiries on the spot, and report to 
their respective governments. Nor has England remained 
a quiet looker-on, as I have had the honour of repre¬ 
senting the Royal Agricultural Society in an investigation 
of the subject, and, in my official capacity, have visited 
Belgium and Germany. Having to report to the Society 
the information I have collected, and also my opinion of the 
value of the operation, I shall be excused by you, at this time, 
of going into full details either of the measure, or my im¬ 
pressions respecting it. It is right, however, that I should 
make a few remarks on the subject. 
The inoculations are made in the belief that pleuro-pneu¬ 
monia is highly contagious, and spreads itself from this cause, 
as well as from the special causes of the extension of an epi- 
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