Hisfojy of Animal Plagues. o^^^ 



Cattle infected in the winter season ; ^ commencing the ist of 



October, 1769, and terminating the 30th of April, 1770 134,696 



„ died in the winter season . . . . . . . . 95,947 



„ recovered in the winter season . . . . . . . . 38,749 



„ infected in the term of three months preceding July, 



1770 ■ . . . . . . . . . . . . . . 3,912 



^ The number of cattle infected in the winter is, in this account, above two- 

 fifths more than in the summer. The reverse of which appears with respect to the 

 plague in the eastern countries, where the contagion of it, for the most part, ceases, 

 or at least greatly abates, in that season. But the principle whence this seemingly 

 great variation arises does not, nevertheless, lie in the nature of the diseases, nor 

 even in that of the predisponent cause of infection in the subjects, which is in fact 

 the same in both, but in the local difference of circumstances with respect to the 

 production of that cause. It is the weakness of the subject in both cases that con- 

 stitutes the susceptibility of infection, and that weakness is induced in different sea- 

 sons from each other by a diversity in the climate and other circumstances attend- 

 ing the places in which the respective disorders, as here compared, prevail. In 

 those eastern countries where the excess of temperature lies in the heat of the sum- 

 mer, mankind, the subject of the plague, are in a too relaxed state, and the juices 

 so putrescent in many individuals as to render them much weaker than in the win- 

 ter, which is there mild and salutary. In the United Provinces, on the contrary, 

 the excess is in the cold of winter, which, being attended with great moisture in the 

 air, makes the cattle, the subject of the murrain, much weaker than in summer, to 

 which the housing them, as is there practised from necessity during that season, 

 much contributes. The increased violence of it in winter and remission in sum- 

 mer, did not subsist here while the disease prevailed in our country in any pro- 

 portion to what it now does in Holland, the less damp state of the air, and the 

 keeping the cattle more out in the fields, having prevented them from being weak- 

 ened by the inclemency of the winter, as there. On the contrary, this was so far 

 from being the case, that Dr Lcgard says : ' This disease being a contagion of the 

 pestilential kind, is susceptible at all times and seasons. In autumn and summer 

 it will rage most, in spring and winter least, according to the alterations commonly 

 happening in those seasons.' He carried it much too far, as is evident by the facts 

 here exhibited, in saying generally the disease will rage most in summer and least 

 in winter, but he spoke from theory only. For supposing, as he intimates, the 

 murrain to be analogous to the plague, he concludes the same effects would always 

 attend the contagion of both without considering the predisponent cause on which 

 the operation of it depends may vary in different places. A more close inquiry, 

 perhaps, into the course of the distemper here would have prevented this error. The 

 whole, however, concurs to demonstrate there is no intrinsic difference in this point 

 betwixt the contagion of the plague and that of the murrain, but that the variation 

 of the effect of them depends on the variation of circumstances respecting the pre- 

 disponent cause in different places. 



* The number of cattle infected in these three months is only in the proportion 

 of about an eighteenth part of those in the winter season, and yet of them near four- 

 fifths died. These beasts may, therefore, be jjresumed to be such as laboured under 

 some constitutional or other peculiar cause of weakness, from which the favourable 

 temperature of the weather could not free them. In June the number infected was 



