PLE URO-PN E UMONIA. 
551 
examination; it is based on ignorance of pathological pro¬ 
cesses, it is an attempt to deceive the unwary, and it is dis¬ 
proved by practical experience. 
But if more evidence were needed of the impotence of 
inoculation as a reliable suppressive measure, it has been fur¬ 
nished during the past twelve months. Altogether some half 
dozen cases have been brought to my notice in which animals 
inoculated by experienced operators have contracted the dis¬ 
ease on its introduction to byres from external sources 
months after the period at which they were operated on, and 
rendered proof or protected against the malady ; but of these 
instances I will only direct your attention to two. In the 
first of these the disease was introduced by a Cumberland 
cow to premises in which stood, in two separate byres (a) a lot 
of cows inoculated successfully six months previously, (b) 
another lot of recently purchased cows which were only in¬ 
oculated at the time of the outbreak. A short time after the 
slaughter of the Cumberland cow, two cows of the (a) lot 
with docked tails developed the disease, but, let it be noted, 
they had never been in absolute contact with the diseased 
cow. 
In the second instance an outbreak of pleuro pneumonia 
occurred in two byres in a well-known dairy district in the 
city, and as a result thereof most of the cows in the adjacent 
byres were inoculated by an experienced operator, and three 
months afterwards a cow in one of these byres developed 
the disease with exceptional virulence, and on slaughtering 
out the herd we did not find another case—showing that the 
malady must have been contracted from the affected animals 
in the adjacent byres. 
Value of Inoculation. 
Inoculation is valuable as an accessory to other and more 
radical measures of prevention and suppression; it never has, 
nor never will, eradicate the disease from any country, and 
those who trust to its doing so trust to a broken reed. If one 
attack of the natural disease will not in every instance pro¬ 
tect against a recurrence of the malady, how can we expect 
