390 
INOCULATION OF SHEEP FOR SMALL-POX. 
In localities in which the flocks have a vast range of herbage for 
the most part uncultivated, in large arable farms where fallow 
constitutes part of the alternations of cultivation, folding is easily 
managed, and maintained for sufficient time to prevent contagion ; 
but in countries richly and extensively cultivated, where fallow has 
in a manner disappeared, and in parts of the country where pro- 
perty is divided, as it is in the plains whereupon the wind, during 
the warm and dry season, may carry the contagion a distance, fold- 
ing is not always practicable; nor can it be done always without 
risk of spreading the disease. I might also add, that it might be- 
come an affair of expense to the farmer, to be obliged to carry all 
the food and water required to the pens. 
Nor is this all. In the case of the natural sheep-pox, the 
duration of sequestration and folding should necessarily bear some 
relation to the continuance of the disease among the flock. Now, 
I have said that this malady exhibits three attacks, or bouffies , and 
that each of these attacks lasts nearly a month ; so that sequestra- 
tion or folding must be persevered in for three or four months at 
least. 
Add to this, that during these three or four months of imperative 
isolation the farmer will not be permitted to dispose of his sick or 
suspected sheep, we shall feel persuaded, as I have said before, 
that the sanitary measures in force at the present day are in most 
cases inconvenient and onerous for graziers. 
In the case, however, in which such measures can be and are put 
into practice, still another question presents itself, and that is, 
whether they really are beneficial and tend to prevent propagation 
of the contagion of sheep-pox. 
So long as the pox is confined to one flock, or in case even it 
should prevail among several flocks in the same commune or locality, 
isolation, whether it be in the pens or the fields, is, generally, the 
only measure that can prevent the spreading of the malady. But 
when an epizootic and fatal pox is spread over a large surface of 
country during a warm and dry season, and at a time that the 
flocks are out grazing, and especially where natural obstacles, such 
as woods, hills, mountains, marshes, and broad streams of water, 
become no boundaries to the infected localities, folding and seques- 
tration being difficult of execution, incessant and often impossible 
surveillance, are the only measures, and they sometimes fail in 
arresting the progress of contagion. The persistence of the sheep - 
pox in 1812 in the department of the Somme, together with its 
introduction into the Pas-de-Calais, and its propagation in fifty- 
nine parishes (communes), the appearance of the malady in seventy- 
four parishes of the Marne, and its duration for nine years in this 
