ACUTE INFLAMMATION OF THE KERATOGENOUS MEMBRANE. 1043 



F. DISEASES OF THE FOOT. 



As diseases of the feet are fully dealt with in Dollar and Wheatley's 

 " Horse-shoeing and the Horse's Foot," it is here only necessary 

 shortly to consider such of the inflammatory processes within the 

 foot as have a direct bearing on veterinary practice. 



(a) Acute Inflammation of the Keratogenous Membrane, 

 pododermatitis acuta. 



Acute inflammation of the keratogenous membrane is, with few 

 exceptions, produced by infection with micro-organisms, and in most 

 cases is preceded by mechanical injuries. On account of the sensitive 

 laminae and sole being bounded on one side by the unyielding horny 

 box, and on the other by the os pedis, inflammatory swelling, especially 

 when of a septic nature, must be painful, and tend to necrosis. The 

 latter, though to some extent antagonised by the great vascularity 

 of the parts, is nevertheless not infrequent. 



The surface of the sensitive membrane possesses a well-developed 

 stratum mucosum, formed of numerous layers of epithelium, which, 

 however, show no horny character. Not infrequently inflammation 

 is entirely confined to this without extending to the corium, a 

 condition termed superficial pododermatitis, in contra-distinct ion 

 to inflammation of the deeper-lying structures corresponding to the 

 corium and subcutaneous connective tissue, which is termed 

 parenchymatous pododermat it is . 



(1) Pododermatitis superficialis generally follows exposure of the 

 tissue of the rete mucosum and entrance of infective material, as in 

 nail puncture. Septic products, &c, penetrate by the nail tract as 

 far as the rete mucosum, and may give rise to extended inflammation. 

 In such cases we speak of a prick or stab. If, on the other hand, 

 the point of entrance was an opening between the wall and sole, 

 the condition is termed separation ; while if it occur in the angle 

 between the bar and wall, it is called suppurating corn. 



Aseptic inflammation of this tissue, though rare, is seen during 

 laminitis and formation of horn tumours, &c. In these cases the rete 

 mucosum is sometimes thickened, as shown in laminitis, by increase in 

 width of the white line. The horn produced during inflammation is 

 sometimes changed in character, stained yellow, or infiltrated with 

 blood (simple corn). Infective pododermatitis superficialis, on the 

 other hand, is always accompanied by suppuration ; the thick layers 

 of rete break down under the action of the infective material, though 

 exudation certainly occurs in the neighbouring portions of the corium. 



3X2 



