518 
MR. JOHN TOMES ON THE PRESENCE OF FIBRILS 
the fibrils which have been drawn out from the tubes. By this procedure some of 
the fibrils will be withdrawn from their normal position in the dentine in the greater 
part of their length, a few of them retaining short lengths of their branches, but 
sufficient to show that they have come from the branches of the dentinal tubes. 
If a carious tooth be selected in which the diseased part is of a deep brown colour 
and of tolerably firm consistence (conditions indicating that the disease has been 
slow in progress), it will be seen, on making a transverse section of the tubes in the 
affected part, that the fibrils have been consolidated (fig. 3) and their outline lost, 
the circumference of the tube alone being distinguishable. Indeed the tubes, when 
in this state and seen in this view, have the appearance of solid rods. But if the sec- 
tion be made in a plane with the tubes, we shall be enabled to trace the calcified fibrils. 
They appear to have a greater power of resisting decomposition than the surround- 
ing dentine, and hence preserve their rigidity. Some will project from the edge of 
the specimen, while others may be seen broken within the tubes, and more or less 
displaced. Were they made of glass the fracture could not be more abrupt and de- 
fined (fig, 4), or their outline more distinct. I have on a previous occasion described 
a zone of consolidation limiting caries* * * § , but I was at that time ignorant of the exist- 
ence of the tube-fibrils, otherwise I should have more fully understood its import. 
Professor Kolliker, in his account of the development of dentine, describes and 
figures processes extending from the peripheral cells of the dentinal pulp in developing 
teeth'f', but he does not recognize the tube-fibril ; indeed he, as before cited, describes 
the tubes as filled with fluid. M. Lent, in a paper published last year, gives a 
similar description to that of M. Kolliker, but says that the cell-fibres are best seen 
in teeth which are but little advanced in development^. Mr. Huxley states that in 
a solitary instance he observed a fibre pass a short distance into the dentine^. 
Both M. Kolliker and M. Lent regard the process which they observed extend- 
ing from the peripheral cells of the pulp in forming teeth, as organisms for the deve- 
lopment of the dentinal tubes. The latter author, near the conclusion of his article 
on the development of dentine, states, the processes of the cells are the dentinal tubes. 
He observes further on, that the fact first observed by Muller and then by Kolliker, 
that the dentinal tubules possess separate walls, which can readily be isolated, is 
explained by the history of the development ; the wall of the dentinal canal is iden- 
tical with the cellular membrane of the ivory cell. 
I do not propose entering upon the subject of dentinal development in the present 
communication, but shall confine myself to showing that the dentinal tubes are in the 
* Lecture on Dental Physiology and Surgery, by John Tomes. Published by Parker, West Strand. 
t Loc. cit. 
X Zeitschrift fiir wissenschaftliche Zoologie, herausgegeben von C. T. Siebolu und A. Kolliker, Sechster 
Band, 1855, p. 121. 
§ On the Development of the Teeth, and on the Nature and Imports of Nasmyth’s “ persistent capsule,” 
by Thomas Huxley, F.R.S., Quarterly Journal of Microscopical Science, No. 3, 1853. 
