These relations of cause and effect between the contagious principle, the predisposition of the animals, and the state of the atmosphere, evidently are subject to some exceptions; but we must allow that in the present epizootic they are absolutely and completely applicable. For, in truth, the years 1864 and 1865 have been distinguished, if not by the persistency of a high rate of temperature not often witnessed, at least by an excessive drought during the months which are both hot and rainy; and this has happened in the various countries of Europe, thereby producing a falling off in the pasture and fodder both as respects their quantity and quality.
As to England, a country usually cold and damp, but renowned for its spacious green fields and meadows, it has suffered more than any other country from these unfavourable conditions, and their destructive influence on the grass and corn; the herds having found a great reduction of food where formerly they met with abundance. Everybody has seen, as we have ourselves, large herds of cattle, wandering in amazement from field to field, and seeking for something to browse on a parched and arid soil. A supplementary provision of corn, roots, malt, and the grounds of the beer vat or spirit barrel, no doubt served to mitigate the sad effects of these privations on the health of cattle; but in spite of all that could be done, their blood became impoverished, their strength and vital resistance sank, and (like the animals which we transferred at will into a soil more favourable to the spread of parasitic diseases), they afforded last June, as they do now, an unusual predisposition to suffer and transform the morbific principles of typhus, which in all probability they would have been proof against at any other time. We may very fairly infer this much, for we must of necessity believe that the regular importation of cattle from those countries which are considered as the permanent focus of typhus, has from time to time transported the miasmatic germs of this malady into England, although the virus did not take effect on British cattle at those periods, for want of one or other of the conditions necessary to its generation and development.