high calkins on the front shoes. In these cases--cases
with an insidious onset--we are inclined to the opinion that the disease
of the horn commences from below, and that the sensitive laminae become
implicated later. Holding this view, one must account for the commencing
disease of the horn by giving, as causes, firstly, those factors (as,
for instance, alternate excessive dampness and dryness) leading to
disintegration of the horn tubules; secondly, the penetrating into and
between the degenerated tubules of parasitic matter from the ground; and,
thirdly, the final breaking up of the horn, and spread of the lesion under
the invasion thus started.

[Illustration: FIG. 129.--DIAGRAM ILLUSTRATING POSITION OF SEEDY-TOE
(INTERNAL). 1, The horn of the wall; 2, the horn of the sole; 3, the cavity
of the seedy-toe; 4, the os pedis; 5, the keratogenous membrane.]

_Symptoms_.--Lameness sometimes attends seedy-toe, and sometimes does not.
This is an important point to be carried in mind by the veterinary surgeon
who is accustomed in his practice to have many animals pass through his
hands for examination as to soundness. An animal with advanced seedy-toe--a
condition constituting serious unsoundness--may walk and trot absolutely
sound, and may give no indication, either in the shape of the wall or the
condition of the sole, that anything abnormal is in existence. Later,
however, after the veterinary surgeon has passed him, the purchaser lodges
the complaint that the horse has a bad seedy-toe, which, so he is told,
must have been there for some time. In this case, culpable though he may
appear, there is every excuse for the veterinary surgeon.

Once the cavity is opened at the toe in the neighbourhood of the white
line, then diagnosis is easy. A blunt piece of wood, the farrier's knife,
or a director may be easily passed into it, sometimes as far up as
the coronary cushion (see Fig. 129). Issuing from the opening is seen
occasionally a little inspissated pus; more often, however, the dry,
mealy-looking detritus to which we have before referred. This form of the
disease we may term 'Internal Seedy-Toe.' for, plainly enough, it has had
its origin in chronic inflammatory changes in the keratogenous membrane.

[Illustration: FIG. 130.--EXTERNAL SEEDY-TOE COMMENCING AT THE PLANTAR
BORDER OF THE WALL.]

[Illustration: FIG. 131.--EXTERNAL SEEDY-TOE COMMENCING ON THE ANTERIOR
FACE OF THE WALL.]

Disease of the horn and loss of its