red with a line, and pulled forward by an
assistant while the cut is being made.

_Third Method (after Bayer)_.--This operator recommends that, after
stripping a half-moon-shaped piece of horn from the seat of operation,
instead of raising the skin of the coronet and the attached coronary
cushion in two flaps (as Fig. 139, a, a), that the cartilage be exposed
by raising up one flap only (Fig. 141, a), consisting of a portion of
the sensitive laminae, the coronary cushion, and the skin and underlying
structures of the coronet.

With the horse cast and the preliminary steps over, the thinned horn of
the quarter is incised in a semicircular fashion, and the half-moon-shaped
piece thus separated from its surroundings stripped off. At about 1/4 inch
from the incision in the horn, a second incision of similar shape is made
through the sensitive structures, which incision is also carried up into
the skin and structures of the coronet. This incision severs, from bottom
to the top, (1) the sensitive laminae covering a portion of the pedal bone
and a portion of the lateral cartilage, (2) the coronary cushion, and (3)
the skin of the coronet and such structures as lie between it and the
cartilage.

[Illustration: FIG. 141.--EXCISION OF THE LATERAL CARTILAGE. (AFTER
BAYER.) The horny wall is stripped off over the seat of operation. _a_,
Semicircular flap of sensitive laminae, coronary cushion, and skin; _b_, the
lateral cartilage; _c_, the sensitive laminae; _d_, the coronary cushion.]

That this incision of the sensitive structures should be kept at 1/4 inch
from the one in the horn has a reason. It is that when this flap is again
placed into position (as later it will have to be) we have round its
circumference a rim of soft structures into which to place the sutures. And
in this connection it is well to advise the operator that the thinness of
the keratogenous membrane (the laminal portion of it) should warn him that
the portion of it to be turned up--namely, that forming the tip of the
flap--should be _scraped_ away quite close to the os pedis. Unless this is
done, there will not be a sufficient thickness left to afterwards bring
into position and suture.

The half-moon-shaped piece of tissue incised is now carefully dissected
away from the external face of the cartilage, until it may be turned up as
a flap (see Fig. 141, _a_), and held from off the cartilage by a tenaculum.

The exposed cartilage is now carefully removed