130 The Cattle Plague and Scientific Investigation. 



illustrations of the value of negative inquiry. He shows 

 most forcibly that investigation is not only useful for the 

 discovery of truth, but also for the purpose of ascertaining the 

 real bounds of knowledge, and of learning the precise force of 

 reason that can be alleged in favour of any particular proposi- 

 tion that authority recommends. 



If the College of Physicians, in 1831, had felt the logical 

 and scientific necessity of negative inquiry and verification, 

 they would not have so completely stultified themselves. They 

 accepted upon authority doctrines which inquiry would have 

 greatly modified, and they assumed propositions to be correct 

 which were known to be incorrect by other persons better 

 acquainted with the case. 



We have only to read the daily papers to see that the frame 

 of mind in which the College of Physicians proved a misguider 

 of those who believed in them, is. now more or less prevalent 

 in many quarters, and were the doctrines and opinions of the 

 ultra-cattle-contagionists acted upon, we might expect a great 

 rise in the price of meat, as the result of a violent interference 

 with trade. 



We are far from contending that the Government should 

 be inert in such a crisis, but certainly one of its primary duties 

 is to collect and arrange facts so as to know what it is about. 

 If every cow from foreign parts is to be treated as Sir H. 

 Halford and his colleagues proposed to treat every individual 

 who had intercourse with a cholera patient, the interference 

 with the import trade of cattle will be vexatious and mischiev- 

 ous in a high degree. If every cow suspected of the disease 

 is to be at once killed, a needless destruction of stock must 

 take place, and if farmers and others are taught to believe in 

 the extremest form of the contagion and infection theory, it is 

 difficult to see how they can shape their conduct by rational 

 rules. 



It is not likely that disorders affecting cattle differ mate- 

 rially from those which affect human beings, and though the 

 records of epidemics point most clearly to measures of 

 caution and prudence, they do not justify the sort of alarm 

 of contagion which runs through most of the speeches we now 

 read. 



The Board of Health Reports on Quarantine abound in 

 illustrations of the fallacy of particular arguments, set up at 

 various times and in various places, concerning the importation 

 of disease and the force of contagion. We have seen how 

 strong was the belief in the professional mind of the conta- 

 gious character of cholera, and yet that has passed away under 

 the influence of a more accurate observation of fact. In like 

 manner it was imagined that quarantine was necessary and 



