Mr Nasmyth on the Human Mouth. 165 



1?he relative perfection of development of the organs ge- 

 nerally, and of the teeth especially, are effected by other 

 causes, viz., the circumstances connected with general deve- 

 lopment, such as the periods of womanhood and marriage, 

 and the habits of life, particularly of females. The nature 

 of the food will always materially regulate the state of the 

 teeth throughout life. 



There is a practical fact of fundamental importance, in 

 reference to this inquiry, which will materially explain and 

 illustrate the points under consideration. It is this, that the 

 natural action of the lower jaw upon the upper may push 

 out, evert, or expand the arch of the upper jaw ; but, on the 

 crther hand, it is impossible by any habitual or natural act 

 performed by the mouth, or by the individual in any way, to 

 bring in, or to contract that arch, so as to produce, out of the 

 prominent jaw of the Negro, the vertical or perpendicular 

 jaw of the Caucasian. The prominent character may, there- 

 fore, be derived from the vertical, but the vertical never can 

 be produced out of the prominent, by habit or exercise. 



The causes which produce the prominent development 

 are palpably of common occurrence, and matters of every- 

 day observation ; and this feature of a race can only be re- 

 claimed by the ameliorating influences of successive genera- 

 tions, in abstinence from practices which give rise to the 

 eversion. Unless, indeed, the perpendicular mouth had been 

 the original presentation of mankind, there is no exercise in 

 which these organs could be employed, so as to develop 

 such a feature ; but I hope presently to shew that the con- 

 stitution of the parts individually, and of man and his man- 

 ners generally, all conspire to the production of the promi- 

 nent mouth from the vertical type. ^ 



The vertical mouth is said to be the original development 

 of the infant Negro ; the advanced mouth of the adult Negro, 

 therefore, is not congenital but factitious. We are also told, 

 that the progeny of the Negro of the southern provinces of the 

 United States, owing to the different circumstances in which 

 he is placed, has not the advanced mouth and its concomitant 

 features after the second or third generations. It will be 

 necessary, however, to shew that these parts are of such a 



