INFLAMMATORY AFFECTIONS 303 



word here. Keratoma may thus be used to describe what 

 we have called keraphyllocele directly that growth makes 

 its appearance at the sole, and is there able to be cut with 

 the knife. Similar hard and condensed growths may, how- 

 ever, make their appearance on the sole in other positions 

 quite removed from the white line, plainly being secreted 

 by the villous tissue of the sensitive sole, and having no 

 connection whatever with the sensitive laminae. They 

 appear as circular patches, varying in size from a shilling 

 to a two-shilling piece. Compared with the surrounding 

 horn, they stand out white and glistening, while in struc- 

 ture they are dense and hard, and offer a certain amount 

 of resistance to the knife. They are of quite minor impor- 

 tance, and, beyond keeping them well pared down, need no 

 attention. Keratoma probably offers us the best analogy 

 we have to corn of the human subject, 



5. Thrush. 



Definition. — A disease of the frog characterized by a dis- 

 charge from it of a black and offensive pus, and accompanied 

 by more or less wasting of the organ. 



Causes. — The primary cause of this affection is doubtless 

 the infection of the horn, and later the sensitive structures, 

 with matter from the ground. Those factors, therefore, 

 leading to deterioration of the horn, and so exposing it to 

 infection, may be considered here. Such will be changes 

 from excessive dampness to dryness, or vice versa ; work 

 upon hard and stony roads ; prolonged standing in the 

 accumulated wet and filth of insanitary stables, or long 

 standing upon a bedding which, although dry, is of unsuit- 

 able material. 



In this latter connection may be mentioned the harm 

 resulting from the use of certain varieties of moss litter. 

 This we find pointed out by J. Roalfe Cox, F.R.C.V.S,* 

 Tenderness in the foot was first noticed, and, on examina- 

 tion, the horn of the sole and of the frog was found to be 



* Veterinary Journal, vol. xvi., p. 243. 



