COMMISSIONER OF AGRICULTURE 273 



of the recovered animal is put out of court by the American and 

 English experience. Hess claims that about 2 per cent, of the 

 recovered 370 Bernese cattle transmitted the disease. But in 

 America in 1870-1 we had the cattle, sheep, goats, deer and swine 

 in 8 states and 2 Canadian provinces exposed to millions of re- 

 covered animals, every member of the new generation just born 

 being a separate test case, and yet not one among this endless array 

 of test cases contracted the disease. The Scottish verdict of " not 

 proven " is much too weak for such a case; the common justifying 

 verdict of " not guilty " seems the only possible and tenable one. 



The same remark applies to cicatrices, scars, and chronic sores 

 after recovery: No case of infection from such chronic or old- 

 standing lesions, a month after recovery, can be conclusively shown 

 in a country in which the acute form of the disease has not sur- 

 vived. All my inoculations from such chronic lesions have uni- 

 formly failed. 



Still less trustworthy are the alleged cases of chronic foot and 

 mouth disease reported by Siegel. dust as Seeley in England, in 

 1839, described an outbreak of aphthous fever in cattle under the 

 name of cowpox, with which h© had been very familiar, so Siege! 

 recorded common chronic affections of the cow's teats as chronic 

 foot and mouth disease. Medical literature is full of such errors 

 made by men who were ignorant of familiar sporadic affections 

 of the genus of animal with which they were dealing:. 



CAUSES 



The one essential cause of foot and mouth disease is the infin- 

 itesimal germ. 



Accessory causes, however, largely dominate in its extension. 

 First and most prolific of evil is the movement of ruminants or 

 swine in an infected country or district. The more extensive and 

 frequent the movement, the greater the advance of the disease. 

 Next follows the great aggregations of live stock in one place, in 

 temporary herds to be again distributed, as in markets, fairs, 

 shows and competitions of various kinds. The great extensions 

 usually follow such large collections of ruminants and swine. The 

 different flocks and herds enter the grounds by common gateways, 

 and as the soil at such points of entry and exit is usually worked 



