ON THE ENAMEL AND DENTINE OF THE TEETH 359 



truth I must confirm — a discovery which greatly enhances the 

 difficulty of accounting for the formation of the enamel." 



Again at page 133 : "From what has been said, it is pretty clear 

 that the membrana preformativa, which may be detached from the 

 enamel in the fcetal tooth, subsequently becomes the so-called cuticle 

 of the enamel, as, indeed, Huxley states." 



Again, at page 130: "When, however, I tested Huxley's new 

 statements, the matter appeared in quite a new light — the more as I 

 could never succeed in discovering a trace of a nucleus in an enamel 

 prism. Huxley, in fact, asserts that the enamel is formed beneath the 

 membrana preformativa, and that the membrana preformativa and 

 cuticle of the enamel are identical. In this point — as I have found by 

 examining the fresh teeth of a new-born child and those of a six 

 months' fcetus — he is about right " 



I wish I could give the entire force of M. Lent's exquisite and 

 polite acknowledgment of the truth of a fundamental fact for all 

 further theories of dental development, but here is the original, for 

 those who can appreciate it : " Hiermit hat es seine Richtigkeitr 



In this part of M. Lent's paper a second misstatement occurs, 

 somewhat more gross, if possible, than that which I have already had 

 occasion to notice. 



At page 131 he says : "Of nuclei such as Huxley describes and 

 figures (in the membrana preformativa), I have seen nothing." 



I have carefully re-examined my own paper, to see if I could find 

 any excuse for a statement so utterly contrary to fact as this ; and, for 

 the sake of MM. Lent and Kolliker, I really almost regret to say I can 

 find none whatever. 



I invariably call the membrana preformativa a structureless mem- 

 brane. I state that Nasmyth's membrane is " about i-25ooth to 

 i-i6ooth inch thick, perfectly clear and transparent, and, under a 

 high power, exhibits innumerable little ridges upon its outer surface,, 

 which bound spaces sometimes oval and sometimes quadrangular, and 

 about i-i sooth of an inch in diameter." And I go on to say that 

 this membrane is nothing but the altered structureless membrana 

 preformativa. I am equally at a loss to discover any figures of these 

 " nuclei ; " though it is possible that in consequence of the reticulation 

 not having been carried evenly all over Nasmyth's membrane in fig. 2, 

 a very careless person might misunderstand the figure — the text 

 however, would at once correct this misapprehension. 



I have neither space nor inclination to follow M. Lent further ; as 

 what has been said proves abundantly the only point worth discussing 

 at all : viz., that the two main facts asserted in my paper are admitted 



