8i8 THE POPULAR SCIENCE MONTHLY. 



jaw, by tracing cases of " surplus " teeth — and certain dental forma- 

 tions met with in the jaws in a large percentage of cases — back to 

 those portions of the jaw in the animal ancestors of man which have 

 disappeared in the course of ages. 



If, in former times, more teeth were met with in the group which 

 was perfecting itself into man, we must be permitted to ask — nay, we 

 are compelled in a purely scientific spirit to ask — whether things have 

 come to a stand-still in this part of our organization, or whether a 

 further reduction is to be anticipated ? Man is certainly one of the 

 so-called " persistent species," but he is not unconditionally stationary. 

 He varies as regards dentition. Imperfect as are our statistics on this 

 point, this much is certain, that the cases of disappearance or loss of 

 teeth most frequently concern the so-called wisdom-teeth, and then the 

 outer incisors. We do not, of course, know how often the question 

 has applied to the actual and complete loss of the teeth, or only to some 

 interference with the teeth cutting the gum, occasioned by a limitation 

 of the necessary space. However, it must be remembered that the 

 shortening of the jaw stands in direct correlation with the reduction 

 of the dentition. A prediction of the man of the future is given us 

 by Cope : the lower races of men will retain the dentition of the pres- 



2.1 2 3 . 



ent day, incisors — , canines --, premolars — , molars — ; while the intel- 



lectually higher races will be distinguished by the dental formulas : 



..1.1 ,2.3 



incisors — , canines — , premolars — , molars — ; 



and incisors y> canines — , premolars — , molars — . 



TVe agree with this in so far that, as a rule, the reduction of the 

 dentition — where the disappearance does not affect the whole set of 

 teeth — can be brought into connection with the idea of progress, and 

 many proofs of this have been given in the course of our discussion. 

 Still, this higher faculty of resistance and of acquiring food is not 

 necessarily accompanied by an increase in the power of the adapta- 

 bility and a perfecting of the intellectual faculties. In the cat we 

 have a more powerful, and hence a higher development of the nature 

 of the rapacious animal than in the dog, with its more old-fashioned 

 form of dentition. Yet who would think of placing cats as intellectu- 

 ally higher than dogs? It is the same with the prospects of the' 

 human races. Modifications in the human dentition are sure to take 

 place — as surely as man can not rid himself of his animal ancestors, 

 even though they may be felt to be inconvenient. But progress in 

 the intellectual and moral domain — and here our well-founded idealism 

 steps in — is not dependent upon the possession or the loss of our wis- 

 dom-teeth. The correlation is not wanting ; but it makes itself felt 

 in an opposite direction. The man who is engaged in making inven- 

 tions and in scientific pursuits, and is advancing and encouraging all 



