Treatise Upon the Genesis and Development of the Dental Follicles to the Epoch of the Eruption of the Teeth. [Volume: 2, Issue: 10, May, 1861, pp. 529-535]

534

THE DENTAL COSMOS.

regular, is afterward reproduced in the crown of the tooth, which, as we
have seen, is moulded exactly upon the surface of the bulb. The bulb of
the canine (c) preserves its conical form a little flattened in one invariable
fashion; this is equally the case in the canine tooth itself: it exhibits
consequently the form of a pyramid slightly flattened from before backward, and a little swollen near the middle.
As to the modifications which the molars (d e) undergo, whatever may
be the number of their tubercles, they appear in consequence of a series
of changes, which are all effected in the same manner; conical at the
blunt summit, and a little elevated as was the bulb, it soon passes into a
very different shape. Its width becomes very much greater in consequence of the gradual enlargement of the base, without the height being
proportionally increased. This enlarged base is surmounted by a blunt
point, which is the trace of the primitive papilla of origin. This is not
found in the centre of the free surface of the bulb, but either entirely
upon the circumference contiguous to the follicular wall, or on a point
very near to that circumference. This projection continues single, as we
have already stated, only during a very short time. A point in the fiee
part of the bulb beside this projection, gives birth to one or two others,
and, following the teeth, to three others, which are single or in pairs
according to the sharp or flat tubercular form of the crown of the teeth.
These projections soon resemble the first, except in size. These new
ones commence under the form of embossments, the nature of which cannot be distinguished at first sight, when they are observed for the first
time, and at the beginning of the development; but all the phases of
their changes can be readily followed in pieces which exhibit the different
degrees of evolution. The projections soon assume, in a manifest manner, the form of papillae, whose summits do not at first reach the same
height. These papillae become developed in length and breadth, and the
bulb, as a whole, soon represents in its turn the shape of the future
crown, with differences in length which are very remarkable between the
different species of animals, and are in proportion to the differences of
form and size of the projections of the crown. At a later period, each
of the small primitive pieces of dentine appear at the summit of the
papillae, and, uniting among themselves, reproduce, as a whole, the multitubercular form of the bulb. (P1. I., fig. 1, m.)*
(To be continued.)
* By an examination of the contents of a groove exhibiting follicles in different
degrees of evolution, it is easy to demonstrate that the bulbs of the molars do not
originate by as many fractions of bulbs (each of which primarily resemble those
of the incisors) appearing in groups, and afterward consolidated into one common
mass marked with eminences, as is the opinion of M. Guillot. (Loc. cit., 1859, vol.
ix. p. 292.)