NEW RESEARCHES tJPON PLEURO-PNEUMONIA, ETC. 461 
It is well to bear in mind that the inoculated digease is trans¬ 
missible to healthy animals only by re-inoculation, as many farm¬ 
ers and cattle keepers are afraid to keep inoculated and healthy 
animals together. 
In non-infected stables where inoculation is performed, the 
cattle will remain perfectly healthy until a new contaminated 
subject is introduced. Then only non-inoculated animals become 
generally diseased, while the inoculated resist the contagion. 
This is invariable, and can be observed wherever the opportunity 
occurs. 
According to the experiments of Prof. Simonds of London, 
and of Henry Bouley, it would appear that the virus of pleuro¬ 
pneumonia remains, so to speak, fixed in the tissues of the animal, 
and does not became diffused in the surrounding air. 
M. Bouley says—“ Experiments were begun in the Boyal Vet¬ 
erinary College of London in 1870, and continued at intervals till 
the end of 1874. During the investigations, several means of 
mediate infections were tried. An animal was exposed to the 
vapors of the- diseased lungs of a cow which had just been 
destroyed and which had been placed immediately under her nose, 
in such a way that they had to pass into the respiratory organs at 
each inspiration. Ho positive result was obtained.'” 
“ In another case, a sponge which had been kept in the nose 
of a pleuro-pneumonic cow, was placed in the nostrils of a healthy 
animal and kept there for half an hour. The results remained 
also negative. 
“ Then,” adds Mr. Bouley, “ there must be some reserve 
made in regard to the various ways in which contagion may fol¬ 
low, and it is to experimentation specially that one must look to en¬ 
lighten our practice as to the surely determined condition of the 
possible modes of contagion, by living or inanimate interme¬ 
diates.” 
Prof. Gamgee of London, says : 
“ An objection made against inoculation, and which equally 
applies to vaccination of man, to variola of sheep, and to rinder¬ 
pest, is that the inoculated disease is contagious, and that by it, 
infecting centers are increased. Tnis objection has no value, at 
