DISEASES OF SHEEP. 81 



It is strange that in Spain, tlie native country of tlie 

 merino, tiae epidemic does not occur — a circumstance which 

 cannot easily be explained by the difference of the climate. 

 Many, and among them high authorities, incline to the 

 opinion that the origin of the disease is not to be sought in 

 foreign sheep of noble race, but that the true malignant 

 epidemic may arise spontaneously and spread by contagion. 

 This point, however, still remains in "doubt among prac- 

 titioner. 



Foot rot is most frequent in merinos, less so in half-breed, 

 and least in common country sheep. Nevertheless, the 

 latter do not enjoy entire immunity from it, as observation 

 has shown ; and the same holds true of the lambs of all 

 races. The more common kinds are less liable, because 

 their wool, skin and hoofs are of coarser texture, while the 

 more delicate build of the merino is not so well fitted to 

 resist the disease. 



If the disease break out in a flock, only a few sheep (or 

 perhaps only a single one) may be attacked at first, and 

 these impart it to the rest. Generally but one claw is at- 

 tacked at- first, and the disease then spreads to the next on 

 account of its close proximity. 



After breaking out, the epidemic spreads under all cir- 

 cumstances, in every season and weather, and cannot be 

 prevented by the greatest care and attention until the 

 greater part of the flock have fallen a prey to it, unless a 

 separation or a cure is effected. 



Its progress is always so slow that in large flocks years 

 may elapse before all the sheep are infected. The conta- 

 gion is facilitated by wet summers or other causes which 

 tend to soften the claws, as heat and moisture combined, or 

 when the sheep stand closely together on warm dung in a 

 stable. Cold and turning out to pasture during dry weather 

 retard the progress of the epidemic. 



