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III. On the Structure and Development of Vascular Dentine. 
By Charles S. Tomes, M. A. 
Communicated by John Tomes, F.R.S. 
Received February 6, — Read March 8, 1877. 
[Plates 3-5.] 
The minute structure and the development of that variety of dentine which is met 
with in most mammalian teeth, and which goes by the name of hard or unvascular 
dentine, have been repeatedly and very carefully worked out, and our knowledge of their 
intimate nature is quite on a par with our knowledge of that of the tissues of other 
parts of the body. But the intimate structure of those interesting and, from a 
morphological point of view, important varieties of dentine, known as vaso-dentine and 
osteo-dentine, is but very imperfectly known ; in point of fact, whilst the arrangement 
of the tubes and channels which permeate their substance has been satisfactorily 
described by many observers, so far as it can be studied in sections of dried teeth, next 
to nothing is with any certainty known as to the contents of these channels, nor as to 
the manner in which they were formed. 
In this paper I propose to give the results of a series of observations upon the 
development of vascular dentine, and the relation which it, in its completed condition, 
bears to the dental pulp ; and I hope to be able to place the nomenclature and 
classification of the varieties of dentine upon a more satisfactory basis, by bringing 
them into accordance with the facts ' elicited by a study of development, which at 
present they are not. 
So far as I can ascertain, although several observers had at an earlier period described 
the tissue which we know as vaso-dentine, Retzius was the first whose descriptions 
were accurate, and how accurate they were is attested by the fact that, so far as they 
go (he having described the hard tissues only), there is now, forty years later, little or 
nothing to be altered in them. But although Retzius recognized and very carefully 
described the tissues in question, he did not give to them any distinctive name, and 
Professor Owen, following in the footsteps of Retzius, introduced the convenient 
terms vaso-dentine and osteo-dentine, and hence ( £ Odontography,’ p. xvii.) claims to 
have been the first to characterise vascular-dentine “ as a component of tooth, £ distinct 
from ivory, enamel, cement, and true bone, and as easily recognisable,”’ so that 
Continental writers often speak of the ££ vaso-dentine ” and ££ osteo-dentine ” of Owen. 
But it should not be forgotten that Retzius, though he did not give a distinctive name, 
MDCCCLXXVIIL E 
