FOOT-ROT. 



465 



Law believed that the disease arose from an undiscovered micro- 

 organism, which was probably present in infected pastures. Others 

 in this country have disputed the contagious character of the disease, 

 and considered that the same conditions of the pasture which 

 produced the disease in a flock would produce it again in imported 

 animals, which would account for the apparent contagiousness. 



Brown, in order to test the question of contagion, placed infected 

 sheep in a pen, the bottom of which was covered with straw which 

 was not removed while the experiments were in process. Three 

 healthy sheep, from a locality where foot-rot was unknown, were 

 placed with the infected sheep. At the end of ten days the feet 

 of the sound sheep were still healthy. Subsequently two of the 

 sheep were inoculated, and it was found that the virus introduced 



FIG. 187. FOOT OP SHEEP SHOWING 

 DISEASE OF HORN (BROWN). 



FIG. 188. SECTION THROUGH THE 

 FOOT SHOWING A CRACK EX- 

 TENDING THROUGH THE WALL. 



subcutaneously in the vicinity of the foot produced the incipient 

 stage of the disease. On making further experiments the contagious 

 nature of one form of foot-rot was established, but it appears that 

 the contagious property is only developed after a long period of 

 exposure, and under certain conditions. On a dry soil the disease 

 will quickly subside, but on moist land the contagious form of foot- 

 rot may be communicated by simple contact, in from six weeks to 

 three months. 



From these and other experiments Brown has drawn the 

 following conclusions : 



1. That so far as the evidence goes it justifies the statement that 

 foot-rot is a contagious disease ; the infective matter being active 

 when brought into contact with the skin between the claws, or 



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