INTRODUCTORY ADDRESS. 
674 
zootic; and that the operation engenders a peculiar state of sys¬ 
tem, which, without imparting the disease itself to the animal, 
gives immunity against the several causes which produce it. 
Twelve hundred cows and oxen have been inoculated in Hasselt 
alone, with, it is said, but ten deaths, and Dr. Willems asserts 
that not one has contracted pleuro-pneumonia, although many 
of them have since been exposed to its contagious influence. 
This number gives but a faint idea of the extent of the prac¬ 
tice, as more animals are daily being inoculated ; and a Dr. De 
Saive, I learn, has operated upon no less than 1.500 in the pro¬ 
vinces of Rhenish Prussia. The government of Belgium is 
carrying out a series of well-considered experiments, under the 
superintendence and direction of scientific and impartial men, 
which doubtless will ere long show if any , or what amount of 
value belongs to the process. At the Veterinary School of 
Brussels there are, at this time, sixteen cows, the subjects of 
the experiment of inoculation, which are to be submitted in 
various ways, and in various places, to the uncontrolled influ¬ 
ence of the disease. Some time ago the government sent two 
diseased cows to Hasselt to be placed with six inoculated ani¬ 
mals, the property of M. Willems, sen. Eight days afterwards 
these two cows died, but the inoculated animals have remained 
unaffected. Two other inoculated cows were sent to a farm, 
and put with thirteen diseased,—they escaped entirely ; while 
of the thirteen, nine died and four were recovered by remedial 
measures. 
In Hasselt, from 1400 to 1500 cows and oxen are kept 
during the summer months, and upwards of 2000 in the 
winter. It is a town full of distilleries, and these animals 
are fed upon refuse grains, &c., and when fat, sent to the cattle 
markets. From the situation, want of drainage, and accu¬ 
mulation of the filth of the town itself, added to the system of 
feeding the cattle, the kinds of food, neglect of ventilation of 
the sheds, and removal of the dung, &c., Hasselt may be con¬ 
sidered as the very centre and focus of a disease like pleuro¬ 
pneumonia. It is said never to have been free from the 
malady since 1836, and hundreds of animals have died within 
it during the last sixteen years; but, by inoculation, the pro¬ 
mulgators of the system declare it is now rendered nearly 
exempt. Whilst these sanguine views are entertained by 
the advocates of the operation, I have become acquainted 
with facts that greatly militate against their conclusions; 
and, therefore, that the foregoing statements may not give 
encouragement to inoculation being tried in this country, 
before circumstances are matured, facts arrived at, and truth 
established, I would simply add, hesitate and be cautious— 
<c think twice ere you act once." 
