History of Animal Plagues. 317 



inoculation of beasts for the murrain does not hinder their receiving the 

 infection again, as other cattle, by accident. This may seem very ex- 

 traordinary on the first view, because, when the cattle take the infection 

 by casual means and recover, they are rarely subject to have the disease 

 a second time, and because we see inoculation for the small-pox pre- 

 vents the ill etfects of future contagion in the same manner as a casual 

 infection. But reasons drawn from analogy, however just they may be] 

 in support of supposition, cannot conceal facts ; and though the cause 

 of this difference betwixt the small-pox and murrain be of a dark and 

 inexplicable nature, yet nothing is to be thence inferred against its real- 

 ity as the subject itself is so in all respects. For there has been no 

 satisfactory reason hitherto assigned why the having either of these dis- 

 eases once, by any mode of infection, should be preventive of the future 

 effects of the same contagion. Whatever difficulties may attend the 

 accounting for it, we yet find on a revisal of the relations of the trials I 

 of inoculation practised for the murrain, a considerable number in pro-! 

 portion to the whole are known to have actually taken the infectioni 

 afterwards, and that of these the far greatest part died of the disease.^ 



1 There are many instances of cattle taking the murrain a second time after having > 

 just before had it by inoculation. Noseman, and two other Dutch physicians, were 

 among the first who performed this operation in Holland. The beasts they inocu- 

 lated were seventeen in number, and out of them three recovered, but took the in- 

 fection again by accidental means a fortnight after in so violent a manner that two I 

 of them died. Professor Grashuys inoculated six beasts, which recovered. All of ; 

 them took the infection again by accident, and four of them died. There is an ac- 

 count, in the experiments of the Marquis de Courtivron, of two calves that were \ 

 inoculated twice without any apparent symptoms of the disease being produced. 

 But they took the infection without any operation afterwards from other cattle hav- 1 

 ing the disease from inoculation, and one of them died. In an experiment made 

 last year on the inoculation of cattle for the murrain, in consequence of a subscrip- , 

 tion formed for that purpose in Friesland, and reported to the States-General ofi 

 the United Provinces by Professor Camper, it appears that out of ten which re- 

 covered after being inoculated the 5th of July, five took the disease again by acci- 

 dental means, and all died. In the continuation of the above experiments, seven 

 beasts which recovered, after being inoculated July 20th, all took the infection again 

 casually aftenvards, and were carried off by the disease. It may seem difficult to, 

 conceive why more of the cattle that have recovered from inoculation, and taken 

 the disease afterwards, should die of it than of those which have not been inoculated, 1 

 and are casually infected with it. But as inoculation does not, similarly to what is I 

 found in the small-pox, prevent the future action of the contagion w ilh equal power, 

 nor render the symptoms less violent when the disease is received by that mode of 

 infection, than when in the natural way, there is room to conclude tliat the weak- 

 ened habit of the beast, in consequence of the injury done by the disease in the 

 inoculated subjection to it, renders the effects more fatal in the second attack accord- 

 ing to the principle we have above specified. 



