The Cattle Plague and Scientific Investigation. 127 



THE CATTLE PLAGUE AND SCIENTIFIC INVESTI- 

 GATION. 



The excitement caused throughout the country by the preva- 

 lence of the typhoid disorder popularly called the "cattle 

 plague/' has not induced a state of mind very favourable for 

 accurate scientific investigation; and yet it is impossible to 

 read the reports of speeches delivered in various districts 

 without perceiving the urgent need of a rigid inquiry. In the 

 absence of accurately collected facts and cautious reasoning 

 we are likely to be afflicted with an epidemic terror, capable of 

 doing more mischief than the disorder that has given rise to it. 

 It is especially the fashion of the hour to assail the foreign 

 cattle trade, and to set up the most violent theories of con- 

 tagion, infection, etc. Those who are familiar with social 

 history will see in these incidents only a repetition of what has 

 often occurred before, and what has been demonstrated to be 

 unreasonable, whenever it has been adequately investigated. 

 No one doubts that a very minute quantity of matter in par- 

 ticular conditions is capable of setting up disease in appropriate 

 subjects; and questions of contagion, infection, etc., really 

 resolve themselves into inquiries concerning the action of 

 infinitesimal doses of poison conveyed by divers methods into 

 the organization of living beings. The surgeon puts a small 

 quantity of his vaccine matter into the arm of an infant, and 

 he thereby sets up a morbid action. The mad dog inserts a 

 probably smaller quantity of a more virulent poison into the 

 body of his victim, and fatal results often ensue. A pestilent 

 marsh gives off in its vapours and exhalations a minute 

 quantity of some matter that has escaped the chemist's 

 investigation, and which may exist in quantities too minute for. 

 his analysis. This morbific matter is breathed for a short time 

 by one passing through the swamp, and he carries away with 

 him a supply of some sort of ague that may last for the 

 remainder of his days. In such cases, and in others that 

 might be easily imagined, we have a transfer of a more or less 

 infinitesimal portion of matter in a particular state, from the 

 situation in which it originated, to some other situation in 

 which it excites chemical or other actions hostile to health and 

 life. 



It concerns not our present inquiry whether the poisonous 

 matter be itself organic, as in the case of fungoid or other 

 microscopic vegetation, or whether it be merely a complex 

 compound undergoing changes by which it is able to excite 

 analogous changes in the complex compounds of which the 

 soft and fluid parts of living creatures are composed. 



