100 ON THE INFLUENCE OF HEREDTTAKY 



wearing of one tooth upon the other. A very 

 remarkable instance of the first kind occurred in 

 a patient under my care at the Ophthalmic Hos- 

 pital for chronic keratitis, a disease which I hold 

 to be always of specific origin. A process of 

 horizontal growing of the teeth has been described 

 by dental authors, which differs from that I have 

 described, by being situated nearer the neck of 

 the tooth. It is often associated with other 

 imperfections in the enamel, and is very well 

 shown in Fig. 6, Plate II., which represents those 

 teeth termed craggy teeth. 



Softness is another* peculiar condition of 

 these teeth. They do not appear especially liable 

 to caries, but wear down remarkably early, a pro- 

 cess of eburnation preventing their decay. Very 

 frequently, the characteristic notch of which I 

 have spoken, is obliterated by this process of 

 premature wearing down. The colour of these 

 teeth is almost always altered, aad they present 

 a dead greyish-white tint, instead of being clear 

 and ivory-like. 



I should like, at this place, to make the obser- 

 vation, that we do not consider what are called 

 " bad teeth " as in any special manner associated 

 with syphilis. The first set undoubtedly decay 

 early, but the permanent teeth do not appear to 

 be unusually liable to caries. 



I shall be asked whether strumous patients do 

 not shoAY teeth presenting the appearance I have 



