346 Proceedings of Poyal Society of Edinbtcrgh. [sess. 
could be imagined to have consisted, at some period of its existence, 
of a row of three pulps arranged in juxtaposition one behind the 
other, and the series of three subsequently folded back upon itself 
so that one of them was brought to the inside or palatal side of the 
others, without interfering with its individual formative growth. 
Perhaps the shortness of the maxillary border might account for 
something of this nature actually occurring by way of affording 
more accommodation. 
Any teleological explanation of such characters in the configura- 
tion of the dental organs here noticed is obscure. Accidental cir- 
cumstances altogether extraneous to the tooth’s development, pro- 
perly so called, may in certain cases possibly exercise some influence 
in their production. The natural growth of the jaw — or, on the 
other hand, its defective or restricted growth — may also contribute 
a certain moulding influence during the later period of the tooth’s 
development. The facts, however, remain the same. Perhaps the 
most important practical bearing exercised upon the wellbeing of 
the tooth, rests in the conversion of the fang from what would other- 
wise be a simple wedge or cone to something approaching a screw ; 
thus obviating the effect of direct pressure or impact in the line of 
the tooth’s long axis, driving it into the socket, with the result of 
deepening and widening it each time such force is exerted, and 
so loosening the implanted fang. It seems, then, unnecessary to 
adduce any greater number of illustrative examples of the con- 
formation than has been here advanced as characteristic of the 
mammalian teeth. There are, without doubt, instances where such 
conformation is far from being obvious, and there are others where 
an undoubted departure from it occurs. But, as a general rule, 
that a typical construction of the kind under notice exists, would 
appear to be sufficiently evident. The remarks here offered are not 
pretended to be either exhaustive or confirmative of the question, 
but are rather intended to be of the nature of a retaining note 
which may be further developed at some future time. 
