308 History of Animal Plagues. 



in parts where the relaxation of moist air, and the debilitating effects 

 of putrid vapours, rendered the cattle more susceptible of all contagion. 

 For, in the beginning of the late king's reign, the disease revived here 

 to such a degree as to give occasion to the Government to make some 

 regulations for the suppression of it, though after a short time the in- 

 fection again seemed to have been extinguished. It also appears to 

 have shown itself in some parts of Germany even to the year 1730- 



' In the year 1740 or 1741, this disease again broke out in the south- 

 eastern parts of Europe, and made its progress through the same coun- 

 tries as in its former course after 1710. 



*■ It was brought hither in 1744 or 1745, from Holland, as is be- 

 lieved, and made great devastation of the cattle for several years, after 

 which it declined considerably, but took fresh vigour in 175*5^ ai^d con- 

 tinued to rage with considerable violence for some time. It then 

 abated gradually, and, as far as appears, the infection, at length, was 

 wholly lost ; as for a number of years we had not the least signs of it 

 before the autumn of the last year, and since, when it is believed to 

 have broken out afresh in two or three places of the island, though not, 

 as there is reason to believe, from any relics of the former, but the in- 

 troduction of a new contagion brought from other countries. In the 

 mean time, though we have been free from the murrain for a number 

 of years, yet it has during that period visited other places. Denmark 

 and Jutland, in particular, felt it in 1769, with greater severity than 

 has ever been known elsewhere. The United Provinces have under- 

 gone a yet harder fate, from some disadvantageous circumstances in the " 

 temperature of their climate. For since its lirst introduction, in 1741^ 

 it has never entirely left them, but maintained its ground, though with 

 various degrees of violence, at ditferent times 5 and at present it makes 

 great ravage in the parts of those countries where cattle most abound. 



' These latter invasions of several parts of Europe by the murrain, 

 have furnished the opportunity of making the following general observ- 

 ations on its effects and consequences. 



' It is to be remarked that as the infection of this disease prevails 

 only at particular times anywhere, and acts with greater violence at 

 some times and in some places than others, according to the preceding 

 view of its migration, so it affects only part of the cattle anywhere, and 

 those with various degrees of malignancy. This leads us to explore iu 

 what this difference of the cattle's being susceptible of the infection, or 

 exempt from its effects, when exposed to it, may lie. On examination 

 of this matter it will appear that where the infection does not before 

 subsist, it never comes but after some general cause has weakened the 

 habit of the beasts in general, such as very severe cold, long-continued 



