8 
J. LAW. 
original sufferer. This, of course, is not really practicable. Yet 
it is instructive to let the mind dwell for an instant on the amount 
of virus produced in the diseased system, and the quantity neces¬ 
sary to infect a healthy- organism. It gives us to realize how 
dangerous is the existence for even a single hour of a beast in 
flie active stages of the disease, how perilous the lodgment of 
this poison in dry buildings where it can be preserved, and how 
full °f hazard the importation of cattle from an infected country. 
With some diseases that inspire greater dread the danger is 
incomparably less. A cow infected at New York with rinder 
pest or aphthous fever, might be sent out to Kansas or Texas, 
but she would show sickness on arrival, and as the disease would 
show itself, after an equal interval, in the herd in which she was 
placed, these would imperatively call for seclusion, and would 
almost certainly obtain it, so that neighboring stock would be 
preserved. But let the contagious lung fever be similarly car¬ 
ried in the body of an animal, and the infected beast will herd 
with the native cattle for a whole month before anything is no¬ 
ticed amiss, and for another month the illness will show in the 
infected animal only. Meanwhile no precautions will be taken, 
so that half the herd may be infected before any danger is sus¬ 
pected. During the interval, by mingling of the infected with 
neighboring herds, the disease is likely to be spread, and if this 
once takes place on the unfenced cattle ranges, it will follow its 
own course in spite of any attempted restraint. Of this we have 
several striking examples. The great herds of the nomadic Tar¬ 
tars, grazing in common on the open steppes of Russia, have been 
afflicted with this, as with other animal plagues, from time im¬ 
memorial. The numberless herds of the Australian squatters 
have suffered similarly since 1859, and the cattle of the Cape of 
Good Hope and Natal have been affected since 1854. Strenuous 
efforts have been made to stamp the infection from each of these 
countries, but the facilities for contagion are too great to allow 
of success; and so it will be with us, should we permit the dis¬ 
ease to gain our open stock ranges. In a country like ours, 
where the disease is more seen but as the result of contagion 
from a pre-existing case of sickness, the presence of even one 
