;oo 
LAMINITIS AND NAVICULAR DISEASE. 
and l unhesitatingly endorse his opinion, that navicular 
lameness is due solely to a strain of the flexor pedis as it 
passes o\er the navicular bone, and that all the changes of 
structure that follow are due simply to this lesion. You 
state that there is a congenital tendency in the majority of 
these cases. This is undeniably true, but I think that this 
tendency depends more upon conformation than upon any 
taint. It is the animal with upright pastern and strong 
stumpy lower articulations and foot. An upright pastern 
should be always looked upon with distrust in all horses re¬ 
quired for speed, and this because, in a leg of this description, 
the flexor pedis forms a much more acute angle in its course 
from the pastern over the navicular bone to its insertion into 
the os pedis, than in a leg with sloping pastern ; this acute¬ 
ness of angle being the reason why it presses more violently 
in its upward movement on the navicular bone, as the foot 
is lifted off the ground, and hence its liability to strain or 
laceration of its fibres. 1 maintain that this may occur in- 
stantaneouslv, but sometimes distinct lameness does not 
become apparent until after repeated slight abrasion of the 
surface of the tendon. Inflammation of all the tissues 
forming the navicular capsule or bursa is the consequence, 
and novvatrainof processesare set up,leading on unfortunately 
to destruction of the integrity of parts. The lacerated ends 
of the tendinous fibres rub against the articular cartilage of 
the navicular bone, ulceration of the cartilage is the result, or 
the cartilage is merely rubbed off, and the articular laminae of 
the bone itself are exposed. Sometimes the progress of the 
disease is stopped at this stage by a deposit of bone being 
thrown out in its stead. This deposit is found to consist of 
small nodules of bone, varying in size from a pin’s point to a 
millet seed, and sometimes larger. Although the animal is 
permanently lame, this lameness is not always excessive, and 
does not increase, if he be carefully used. I have proven this 
point to my own satisfaction by post-mortem examinations of 
cases that I had known for years before death. Supposing 
the disease advances, ulceration of the bone is found to exist: 
this morbid process goes on within the bone, from inflamma¬ 
tion of its structure having been excited by injury from with¬ 
out; ulceration of the bone commences within its cancellated 
structure, and extends to the articular surface by removal 
from within of the hard outer covering of bone which closes 
the cancelli on the surface covered by cartilage. I maintain 
that you interpreted wrongly this morbid process when you 
state that ulceration of the bone takes place without ective 
inflammation of the articulation. I agree with you when 
