FOOT-EOT IN SHEEP. 399 



ducts of foot-rot must be determined by experiment; and the 

 only foundation for the assumption of ' virus ' lies in the fact 

 that the introduction of the matter from a diseased foot to the 

 healthy foot by puncture through tlie horn has produced foot-rot 

 in some cases, although it has failed to do so in others. 



" After all, the fact may be admitted without any question ; 

 it proves very little. We are quite prepared to learn that an 

 injury to the horn of the foot, followed by the contact of a mix- 

 ture of moist epithelial cells and particles of dirt, will, if applied 

 sufficiently long, produce foot-rot; we know that dirt and moisture 

 will suffice, without any additional elements. 



" Some of the experiments in inoculation failed, probably 

 because there did not happen to be enough of the gritty particles ; 

 others because they did not remain long enough in contact with 

 the membrane to establish any irritation; and at best there 

 was not so much disease produced as would have occurred if 

 the animals had been placed upon undrained land, where there 

 happened to be a tolerably plentiful admixture of sand or grit 

 in the soil. 



" If it had ever been found that the introduction of the 

 matter under the skin of the leg or any part of the body pro- 

 duced the disease, there would be fair evidence of its specific 

 nature; but in the absence of this proof, we cannot admit 

 an assumption which is altogether unnecessary to explain the 

 results. 



" From the present state of the argument, w^e may consis- 

 tently deduce the conclusion that ' foot-rot ' is primarily con- 

 sequent upon such a derangement of the structure of the horn 

 as permits the introduction of foreign particles, which ultimately 

 reach the internal membrane, and occasion irritation, followed 

 by exudation and excessive secretion." 



For some time past my attention has been very much directed 

 to this matter, and from my own observations, very carefully 

 made, and from information gathered from many eminent flock- 

 masters and their shepherds, I am quite satisfied that diseased 

 sheep may, without fear of infection, be allowed to mix with 

 sound ones on dry lands, and that consequently foot-rot is a 

 non-contagious malady, and that it is manifested in two ways. 

 First, Sheep pastured on gravelly or sharp sandy farms, wear 

 away, especially in wet weather, the soles of their hoofs, and 



