NOTES ON ODONTOMES. 
85 
face due to the rapid wearing away of soft ivory in aged horses— 
in which class of animals the so-called caries is wanting. 
2. The absence of the ivory column at some portion of the 
tooth from crown to fang, the adjacent enamel layers being free 
from any remnants of dentine which should here and there per¬ 
sist in genuine necrosis of ivory. 
3. A total absence in superior molars of the column of ce¬ 
ment which should fill the central infundibulum of enamel from 
table to fang. 
These two latter conditions inevitably lead to early longi¬ 
tudinal splitting of the tooth. If the cement fails to form with¬ 
in the central infundibulum, food presses into the cavity as soon 
as the tooth erupts and fracture of enamel into pulp cavity 
quickly results. If dentine fails to form, the tooth has not been 
long in wear until the arch of enamel wears through, exposing 
the vacant ivory space with impaction of food, infection, suppu¬ 
ration, fistulse, etc. 
Thus we find explanation for the fact that most major dental 
operations on horses are called for upon young animals ranging 
from two or three months to five or six years of age, or if in 
aged animals, these have a history of disease dating back to early 
life. 
In our prior contribution we described and illustrated epithe¬ 
lial or enamel, compound follicular, radicular or dentine and 
composite odontomes, follicular cysts and cementomata. We 
desire to add two unique cases, one a fibrous odontome, com¬ 
pleting the list of species as described by Sutton, the other a 
multiple composite odontome, representing gross aberrations in 
the tooth germs of three or four contiguous superior pre-molars. 
Heretofore fibrous odontomes have been recorded in rickety 
children and young caged animals, but so far as we have found, 
not in the horse. 
The patient was a 12-year-old black mare of common breed, 
reared in a locality where osteoporosis and perhaps other related 
maladies are not uncommon, but offering no history of constitu¬ 
tional affection. She was thrifty and apparently sound until 
