RAINEY, ON DENTAL TISSUES. 223 
further found, when the jaw of the foetal calf with the tooth- 
sacs entire within it, had been kept until decomposition 
commenced, that on opening these sacs the cusps were 
coated in parts with phosphate-crystals sufficiently large to 
be visible without the aid of the microscope. This circum- 
stance is most probably due to the decomposition of some 
animal substance required to keep the phosphates in solution, 
and the subsequent dissipation of its elements in the condi- 
tion of carbonate of ammonia, &c. Now, if we suppose that 
this albuminous fluid, holding in solution phosphates and 
some of the other constituents of enamel, elaborated by the 
enamel-organ, be applied by the ends of the enamel-cor- 
puscles, to the external surface of the previously formed 
layer of enamel-matrix ; and that this matrix is moistened 
by a fluid containing in solution a salt or salts capable of 
decomposing those furnished by the enamel-organ, and so 
combining with them as to precipitate coalescing particles of 
enamel such as have been described, we shall have, in 
principle, exactly what takes place in the formation of shell- 
tissue. (See this demonstrated in my work ‘ On the Forma- 
tion of Shell and other hard structures.’) As to the manner 
in which these organs act in elaborating their respective 
substances with the albumen necessary to give them their 
globular coalescing property is not at present known, and 
a more refined chemistry than has yet been applied to this 
branch of physiology would be required to throw light upon 
the subject. What has been stated in reference to enamel 
and the enamel-pulp will apply equally to dentine and its 
pulp, as also to bone, as has been shown in the article 
“Bone,” in the volume before alluded to. As in the preced- 
ing explanation of the mode of formation of the dental 
tissues, no mention is made of any influence but what is 
chemical and mechanical, it is probable that if this paper 
were thus to conclude, it would be inferred that I had no 
belief in the participation of vitality in the several processes 
concerned in the production of these tissues; and thus an 
opportunity would be afforded of representing all that has been 
stated as absurd and ridiculous. Consequently a few remarks 
on the influence of vitality in the processes above explained 
will be necessary. Now, it is certain, from the foregoing 
account of the formation of the dental tissues, as observed 
in tracing their development from the condition in which 
they are found on first assuming a visible existence up to 
their completion, that both chemical and physical effects 
have been produced,—that new compounds have been formed 
is a proof of the one, and the definite forms which have 
