LOCAL NON-COSITAGIOUS DISEASES. 315 



this is all produced by wet. In a few days, perhaps, we have a 

 change of temperature ; evaporation is produced from the surface 

 of the land and from animal bodies as well, and the ground be- 

 comes drier. A reaction takes place; the circulation is quick- 

 ened ; the hoof swells or rather is pushed from the parts beneath ; 

 the skin between the claws inflames; the heels bulge; the coronet 

 enlarges; abscesses form; matter penetrates between the horn and 

 the substance beneath, and disunites the sensitive from the horny 

 laminae, and, in the worst forms of the disease, the hoof falls 

 off." 



This description by Mr. Eead very properly and accurately 

 covers the subject, given the cause, namely, prolonged unnatural 

 surroundings, and it is not necessary to have any specific germ to 

 assist in producing the changes in the hoof-horn. The fact that 

 so many members of a flock appear to become affected simulta- 

 neously, is easily explained, they all having been subjected to the 

 same cause. The hoof to maintain its normal healthy condition 

 must be submitted to a certain amount of wear and tear, other- 

 wise the horn being continually under the process of formation, 

 unless worn off and kept to its proper proportions, would grow 

 abnormally long and favor changes in the horn substance. For 

 this reason foot-rot is at times met with on dry, sandy soils, the 

 softness of the soil not furnishing sufficient wearing properties to 

 the feet. The mere fact of healthy sheep contracting foot-rot 

 from being placed with those already diseased, in no manner 

 proves that the disease is contagious, as the sheep are submitted 

 to the same causes which produced the condition in the former. 

 The form of the disease met with on high, gravelly soil is pro- 

 duced from an excessive wearing away of the claws from contact 

 with sharp, gritty particles, and while they go lame and at times 

 abscesses form with fungoid growths of horn, it cannot be said to 

 be malignant foot-rot, meaning the kind which arises from moist- 



