Page:Popular Science Monthly Volume 28.djvu/838

 jaw, by tracing cases of "surplus" teeth—and certain dental formations 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 present day, incisors $$\tfrac{2}{2}$$, canines $$\tfrac{1}{1}$$, premolars $$\tfrac{2}{2}$$, molars $$\tfrac{3}{3}$$; while the intellectually higher races will be distinguished by the dental formulas:

We 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 adaptability 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 intellectually 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 wisdom-teeth. The correlation is not wanting; but it makes itself felt in an opposite direction. The man who is engaged in making inventions and in scientific pursuits, and is advancing and encouraging all