612 OPEKATIONS ON THE FOOT. 



and then it seldom produces lameness. Sometimes the marks are 

 arranged in layers, the healthy horn being alternated with others 

 which are infiltrated with blood. This is a proof of the intermit- 

 tent character of the acting cause which has originally produced 

 the corn. The ecchymosis, however, is not the actual seat of the 

 corn, which is more in the velvety and especially in the laminated 

 tissues, which are torn or bruised, the blood escaping thi-ough 

 the sole simply by the action of the laws of gravitation. It is 

 rarely that this lesion is looked for in the case of dry com, and it 

 is usually ignored; but in the confirmed corn, a true alteration of 

 the laminse of the keraphyllous tissue is observed. This is re- 

 placed by a horny tumor, a kind of keraphyllocele, analogous to 

 that of chronic laminitis, due to a union of the laminse under the 

 influence of the fibro-plastic exudation resulting from the inflam- 

 mation, which is of varying size, and presses more or less on the 

 sub-horny tissues. In some cases, this horn breaks up little by 

 Uttle, and gives rise to quarter crack. The ecchymotic spots of 

 the dry corn may vary in size ; they may range from the size of a 

 pea to that of a ten-cent coin. At other times they may occupy 

 the entire space between the bars and the walls of the foot. 



In moist corn, there is not only hemorrhage, but also inflam- 

 mation proper, with serous exudation. The hoof is colored, as in 

 dry corn, of a brownish tint, due to the infiltration of blood which 

 occm-ed at the start ; on searching deeper, one will discover be- 

 tween the hoof and the living tissues beneath a separation of 

 varying dimensions, fiUed by citrine serosity. Most frequently 

 this separation takes place at the line of the sole with the wall, 

 and extends under both. The horny svibstance is then more or 

 less impregnated with this serosity, and then has a charcteristic 

 yellow appearance and a waxy consistency. 



In suppurative corn, or more properly, suppurating, the in- 

 flammation ends in sujjpuration. The pus is secreted by the vel- 

 vety and laminated tissues. It makes room for itself by gradually 

 separating the hoof as its formation progresses. Before long it 

 passes between the podophyllous grooves of the bars and of the 

 quarters, the horny are lessened from the fleshy laminse, and in 

 its ascending progress the pus soon makes its appearance between 

 haii-s and hoof at the quarter, at the heels, or at the glomes of the 

 frog. It is not common for the pus to make its way through a 

 hoof of too thick or resisting a nature, unless it has first been 



