16 
EDWARD B. POULTON. 
rous in any of the sections, the number is probably normal, as 
judged from tbe retracted fibres seen in fig. 2. The staining 
of the inner layer of recently formed dentine is peculiar 
(PI. Ill, fig. 1, d'), for as a rule this part of the tissue stains 
less in reagents. But this is also probably an accidental result, 
for I noticed that some of the decalcified teeth were normal 
in this respect. The reticulate outer margin of the recently 
formed tissue shown in fig. 1 is also peculiar ; but here again 
other sections which had been treated differently showed a 
margin nearly parallel to the dentine surfaces, such as is usually 
described. It is noteworthy that the former appearance in the 
less altered tissue shows a margin which extends irregularly 
into the calcified dentine, of which parts constricted off and 
remaining uncalcified would produce the appearances known 
as “ interglobular spaces.” The faint oblique lines on the den- 
tine in fig. 1 are probably produced by cracks in the brittle 
tissue caused by the razor. The decalcified tissue stains deeply 
(fig. 2) ; the older part of the more normal tissue remains un- 
stained (fig. 1). Interglobular spaces are represented as black 
marks. 
3. Enamel. — This tissue is of very normal appearance. 
The prisms are seen in transverse section in PI. Ill, fig. 3, 
and in longitudinal section in fig. 1, e. The line between it 
and the dentine is very smooth and continuous, while that be- 
tween it and the enamel cells (fig. 1, e. c. ) is very irregular. 
Thetisssue stains faintly round the projections of the cells into 
it, probably on account of less complete calcification. The 
prisms are oblique to the enamel cells (fig. 1). I could not 
determine whether each cell exactly corresponds to a prism, 
but this is doubtless the case. The layer is finely striated 
parallel to the surface, probably due to tbe transverse striations 
of each prism. The prisms must vary in size, for figs. 3 and 1 
are magnified to an equal extent. 
The layer of enamel is especially thick at the apex of the 
teeth. It is thinnest on the third tooth. 
4. Inner Epithelium of the Enamel Organ — the 
Enamel Cells. — These are normal, long and thin where 
