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atrophy of the enamel occurred. But the chart is pretty
nearly correct in all except the last figure. I suppose I got
in a hurry there and didn't consider that line carefully ; it
ought to have shown the roots of the, cuspid and bicuspids
unfinished in the eleventh year. And, what is worse, that
little bit of carelessness has been copied pretty much all over
the world; die wdiole chart, indeed, with its error as w^ell as
its facts.
Now% in considering the lengthening of the roots of the
teeth we must give about another year after the root has at-
tained properly its length for the reduction of the size of the
apical foramen. I should say in the first molars, coming
through at six years, the length of the root is complete at
from ten to twelve years; that is giving from four to six
years after its eruption. With the incisors, erupting at seven,
the foramen will be closed at about ten to twelve years, giv-
ing three to five years after eruption. With all of the other
teeth we may give from three to four years after eruption.
The laterals comie through at eight, will be completed from
eleven to tw'elve; the first bicuspid comes through at ten and
will be completed at from thirteen to fourteen ; the second
bicuspid at very nearly the same time. The cuspid will be
complete at about fifteen to sixteen, coming through at
twelve. I doin't know that I have seen a cuspid that was not
complete at sixteen, yet I know of several cases where they
were decidedly incomplete at fifteen, and generally we find
them incomplete at fourteen. We occasionally have condi-
tions calling for the destruction of the pulp in the second
molar before the roots have been completed. I have been in
trouble a number of times myself, where I destroyed the
pulp of this tooth too early, removed the pulp and found
broad, open apical foramina that defeated root filling. We
cannot calculate certainly that this tooth will be completed
before the person is fifteen or sixteen years old.
Now, in cases of delayed eruption we should always be
on our guard as to the filling of the roots. A patient may

come to us with a tooth in position, and without gaining a
history of the tooth we may not know that it has been de-
layed in eruption and get into trouble because of the lack of
development of the root. One case came to me a number of
years ago, where a friend of mine got into difficulty, and got

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