CHRONIC INFLAMMATION OF THE SENSITIVE LAMINAE. 
811 
point the reader is referred to Dollar and Wheatley’s “ Horse-shoeing 
and the Horse's Foot,” p. 896.) 
(b) Chronic Inflammation of the Sensitive Laminje, 
PODODERMATITIS CHRONICA. 
Chronic inflammation of the sensitative laminae follows slight but 
continually-repeated mechanical irritation or other injury, the nature 
of which is at present imperfectly understood. The former class was 
studied and described by Lungwitz. Certain portions of the hoof grew 
with excessive rapidity and became thickened, sometimes causing horn 
tumours (keratomata) and chronic lameness; sometimes chronic 
inflammation occurs in the sensitive laminae, and interferes with horn 
production, producing “ seedy toe.” 
As a rule, these processes are all very obstinate. One section has 
little surgical interest, and, therefore, need not be considered here. 
These conditions are considered at length in the above-mentioned 
work. 
I.—KERATOMA. 
The horn forming the inner surface of the wall at the point where the 
wall is united to the sensitive laminae may become thickened, producing a 
new growth, which is variously known as keratophylocele, keraphyllocele, 
or keratoma. The activity of secretion in the coronary band is very 
great; in the sensitive laminae, on the other hand, it is very small, being 
only well marked at the upper part of the wall just below the coronary 
band itself, where the horny laminae originate. Throughout the rest of 
the wall secretion is almost nil. But when the tissue becomes the seat 
of chronic inflammation, its secretory activity is exalted, and a mass of 
new horn is produced, which we recognise as a keratoma. Such growths 
sometimes start from the coronet, in consequence of treads or other 
injuries producing chronic inflammation and hyperplasia in the lower 
papillae of the coronary band. This pathological thickening gradually 
extends downwards towards the ground surface of the foot, and, pressing 
on sensitive structures, gives rise to chronic lameness. 
In other cases the sensitive laminae form the points of origin of 
keratomata. In this case the irritation starts in the white line, being 
either set up by a misdirected nail, by separation of the wall, or by 
cracks in the horn. Keratomata so formed are confined to the lower 
portions of the wall, and though occasionally they extend upwards in 
the direction of the coronet, they seldom reach it. 
Such thickenings, of course, press on the sensitive laminae and os 
