462 INOCULATION FOE PLEURO-PNEUMONIA IN CATTLE. 
animal bore up under the depressing and destructive influ- 
ences of the disease in its active form for the somewhat 
lengthy period of twelve days, when death put an end to her 
sufferings. The post-mortem appearances agreed in every 
particular with those seen in similar cases. 
Jan, 6th, 1853. — The five cows were again inoculated in a 
manner somewhat modified from the former. The skin of the 
perineum was scratched with a lancet, sufficiently deep to 
cause a very slight oozing of the blood from the numerous 
erasions, and then upon these places a portion of diseased 
lung , well charged with serous and fibrinous effusions , was rubbed 
for the space of two or three minutes. The cases were 
most assiduously watched, so that the slightest indication of 
the action of the fluid, if specific, would have been observed, 
but nothing took place even from this plan of operating. 
14 th . — We determined to give trial once more to simple 
erasions of the cuticle, and to-day inoculated the five cows 
belonging to Mr. Paget, together with another cow admitted 
into the infirmary for mammitis, and also a heifer under our 
care for lameness. Groups of erasions, varying in number 
from twelve to twenty, were made on the labia, perineum , and 
under surface of the tail, in each animal, and upon these the 
serous exudation was rubbed with the finger for not less than 
from four to five minutes. No specific effects followed. 
20 th , — Inoculated each of three of the cows again, which 
had been chiefly the subjects of the foregoing experiments, 
with two deep punctures made with a grooved needle, and the 
two others with four superficial punctures, all of which, like 
the preceding inoculations, also proved abortive. 
It appears pretty certain from these experiments that slight 
punctures, and also scratches of the skin, will invariably 
fail ; a fact which of itself is almost sufficient to disprove the 
existence of any “ special virus” being contained in the 
exudations from an affected lung. Every person of expe- 
rience in these matters knows full well that success of in- 
oculation, both with regard to the local and constitutional 
declaration of the symptoms, depends on the smallness of the 
quantity of the virus employed, and the minuteness of the 
puncture by which it is introduced into the system. 
The virus of Pleuro-pneumonia, if the exuded fluid may be 
so called, would not, in our opinion, as an animal poison, be 
an exception to the law which governs the extension and 
reproduction of such poisons. It was clearly ascertained with 
regard to the smallpox of sheep, at the time of its great pre- 
valence, that inoculations which were made by deep punctures 
and the introduction of three or four ordinary drops of the 
