RINDERPEST. 
161 
less widely, according to the freedom of movement in live stock. The 
natural corollary is, that having been thus permanently settled on the 
European continent, where it does not originate spontaneously, it may 
be domiciled and perpetuated with equal facility on the American, and 
may prove quite as difficult and expensive to eradicate. 
DIFFUSIBILITY OF THE VIRUS THROUGH THE AIR. 
The contagion of rinderpest is remarkable in this, that it does not 
spread very widely through the atmosphere. That the microscopic par¬ 
ticles which bear the contagion arise and float upon the atmosphere, 
there can be no doubt, and that every diseased animal, every carcass, 
and every fresh product of such carcass, is surrounded by a virulent 
atmosphere, which will infect all susceptible subjects within its area, is 
as certain ; but this infecting condition of the air is comparatively cir¬ 
cumscribed. With a favorable wind and a damp atmosphere (the most 
favorable conditions), Korber, Stepanoff and Pozockow found that 
it did not exceed 800 metres (yards). Prof. Hayne found that it 
varied from 30 to 1,000 metres. Abilgaard sets it down at 108 metres ; 
Gerlach at 40 metres; and Roell, Jessen, Haupt and others at from 
10 to 40 metres. Where the atmosphere is still, the shorter distances 
are nearest the truth ; thus, Reynal mentions that a great number of 
stables kept healthy within 40 and 50 metres of a badly infected one 
during the Parisian epizootic, in 1871. In London, in 1866, the exper¬ 
imental stables at the Albert Veterinary College were separated by a 
wall only from a large dairy, and yet the cows in the latter preserved 
good health for over a month. More than this, healthy and diseased 
animals were kept in stables placed side by side, and with their doors 
opening close together into a confined yard, and the same attendant re¬ 
gularly feeding first the healthy, and then the diseased, yet the former 
escaped for over a fortninght, until, indeed, a visitor went straight from 
the sick to the healthy, and infected them. 
It must always be borne in mind that the virus may easily be car¬ 
ried long distances on dry hay, paper and other light objects blown by 
the wind, as well as on the feet of men, quadrupeds, birds and perhaps 
even insects; but its diffusibility through the air, without any additional 
medium, is by no means extensive—a fact which should inspire us with 
the greatest confidence in the measures at our command for checking 
its progress, and should be our warrant for carrying out these measures 
with the most unflinching stringency and impartiality. 
