32 The Cattle Plague. [Jan., 
where by so domg you can kill an isolated germ of disease in- 
stead of suffering that germ to linger and fructify while you are 
attempting a cure, for the precarious prospect of an insignificant 
saving,—is justified by reason; it is also directly justified by 
experience, which shows that while the plague, propagated from a 
single germ, speedily becomes unmanageable, spreads from herd to 
herd, from province to province, and from country to country, 
multiplies in a continually increasing ratio, and exhausts itself only 
after ruinous havoc and a long course of time, it may be effectually 
eradicated by prompt and unsparing measures. The experience of 
Prussia is especially valuable in this respect. The plague has often 
appeared, says Professor Gerlach, in the provinces bordering on the 
Russian empire, in East Prussia, Posen, and Silesia, but it has never 
since 1815 penetrated eastwards, even so far as Brandenburg. Lastly, 
we must add, it has not been found to give way before cold weather 
or rain. The reverse seems to be the case. It is worse, Professor 
Gerlach informs us, ‘ in cold and wet weather, and better in warm 
and dry weather.’ ‘It spreads, says Mr. Ernes, ‘as fast in a cold 
as in a hot season. The murrain of 1745 broke out here in early 
spring, the temperature of the preceding year having been low; 
and it is stated to have raged most violently during the winters, 
and to have diminished in intensity with the advance of summer. 
“ These conclusions, which are all that for our present purpose 
it is necessary to state, are far, of course, from exhausting all that 
is known upon the subject. Beyond what is known, however, there 
is a large field of inquiry which may be usefully explored. To 
observe carefully the premonitory and progressive symptoms of the 
disease under various conditions—to determine precisely the period 
of incubation, the effect of remedial and of preventive agencies 
(including under the latter head disinfectants, therapeutical measures, 
and inoculation)—to ascertain within what range and under what 
modifications the poison may be communicated from a diseased cow 
to other animals of the same or different species—these are branches 
of investigation practically important, but which will take time. 
With a view to the thorough examination of them, we have 
obtained the assistance of men eminent in various departments of 
science, and we hope to be able to report on them hereafter. But 
we have now to deal with more pressing questions. Are the 
measures hitherto adopted to stifle the plague at home and stop 
its entrance from abroad effectual for the purpose? If not, what 
other measures are likely to be effectual? To these questions, 
having early satisfied ourselves of the general character of the 
disease, we at once directed our attention; and the evidence which 
we have received has been chiefly taken with a view to them.” 
