170 
Concluding Report on the Experiments at the 
side, was dark-coloured and full of blood, but its tissue was healthy and cre- 
pitant throughout. Along the thin margin of the middle part of the left lung 
there existed a patch of partially consolidated tissue, about three or four inches 
in extent. The firm straw-coloured exudation, which was confined to inter- 
lobular tissue, not invading the lobules themselves, varied in thickness from 
to A inch. When cut, no juice exuded from the surface, such as is 
always seen in cases of acute contagious pleuro-pneumonia. 
The whole appearances showed conclusively that this exudation was not 
the result of any recent inflammatory action, but some old morbid process in 
the interlobular tissue. 
In addition, about the middle of the su]3erior aspect of the left lung, there 
existed a cavity bounded by a strong resisting membrane containing a mass 
of dead lung, the remains of the interlobular tissue being easily made out 
under the microscope. This piece of necrosed lung was as large as an egg, 
and was infiltrated and partially surrounded by cheesy material. 
Such cavities, containing portions of dead-lung tissue, have frequently been 
met with in the lungs of cattle which have recovered from limited or partial 
attacks of pleuro-pneumonia. 
Professor Brown, in the Annual Report of the Veterinary Deijartment of 
the Privy Council for 1876, at pp. 18, 19, describes a case of this kind where 
the animal was slaughtered eleven months after recovery. 
The French Commission, in reporting the results of their experiments in 
1854, stated that in six out of eleven iminoculated animals that had been 
exposed to the influence of contagion by three months' cohabitation with 
diseased animals without apparent result, they found portions of dead lung 
encysted. This would go far to show that these six animals had been the 
subjects of limited attacks of the disease. 
APPENDIX V. 
Inoculation by the infusion of Pleuro-Pneumonia Virus into the blood. 
In performing inoculation by this method, the vein running down the back 
of the ear was selected on account of its moderate size and sujjerficial position. 
The vein was exposed by a small incision in the skin, and the sharp-pointed 
steel cannula of a subcutaneous syringe introduced into the vein, and the 
fluid obtained from the diseased lung slowly passed into the blood-stream by 
the syringe. The vein was afterwards secured by a ligature, and the small 
wound in the skin closed by a suture. In the first attempts at inoculation 
by this method, it was found that the ligature of the vein and the suture 
in the skin caused some swelling which did not subside in less than 
fourteen days. It was also seen that by making an incision in the skin, 
the risk of introducing the virus into the cellular tissue, which has since 
been proved to be extremely dangerous, was very much increased. It 
was afterwards found that, with the exception of one case in which the 
vein was very small, in a calf about two months old, the incision in the 
skin could be dispensed with. By shaving the hair off the spot selected 
for the operation and applying pressure so as to cause the distention of 
the vein by blood it could be distinctly seen, and a fine-jwintcd steel cannula 
jiassed into it in the direction of the blood-stream. That the cannula was in 
the vein itself, and not merely lodged in the sheath or surrounding cellular 
tissue was readily demonstrated by allowing a few drops of blood to flow 
before attempting to inject the virus. By this means the risk of inoculating 
the cellular tissue was reduced to a minimum if not entirely avoided. The 
application of slight pressure over the vein ibr a few seconds after the with- 
