678 
J. A. COUTURE. 
ORIGINAL ARTICLES. 
VETERINARY OPHTHALMOLOGY. 
By J. A. Couture, V.S., Quebec. 
Specially Written for the American Veterinary Review. 
ULCERATION OF THE CORNEA ; FALL OF THE CRYSTALLINE 
LENS. 
This disease is very common in dogs and men, and those 
veterinarians who have a little dog practice have often met it 
either on old subjects or as a complication of distemper. But, 
if I am not mistaken, the displacement of the crystalline lens 
and its falling out of the eye is a very rare occurrence in dogs, 
though it is not of uncommon occurrence in man. 
In order to better understand the case it may be useful to 
expose in a few lines the causes, symptoms and termination of 
the disease. 
Ulceration of the cornea is never of an inflammatory nature • 
on the contrary, it is the consequence of defective nutrition 
bringing a passive processus , called by some degeneration , but 
more properly described by Trasbot under the title of necro¬ 
biosis. This Alfort professor has so well described both these 
passive processes (necrobiosis), and the ulceration of the cor¬ 
nea, that the readers of the Review will forgive me if I quote 
him largely in this article. 
Necrobiosis is the term employed by Virchow to designate 
the progressive mortification , followed by gradual destruction, 
without putrefaction, of anatomical elements situated in the midst 
of living tissue. It differs from necrosis. Necrosis is charac¬ 
terized by gangrene of all the elements of the parts affected ; 
necrobiosis is characterized by death and gradual disintegra¬ 
tion of the affected part. 
Necrobiosis occurs physiologically in secretion of sebaceous 
glands, secretion of mammary glands, some mucous secretions ; 
it occurs pathologically in all fatty degenerations and fatty 
infiltrations, it occurs also in the disintegration and absorption 
of blood-clots when haemorrhage has taken place in the tissues, 
