1890] * The Teeth as Evidence of Evolution, 235 
are for theirs. But even within the question of the perfect angle 
of the human jaw there is something suggestive®of evolution, for 
among the mammals there is every gradation from the long jaw 
with its acute anterior angle and narrow base to the ampler 
anterior angle and broader base of the human jaw. There is a 
constant shortening and recession of the jaw as we approach 
man, and even in the races of man himself, we see the same gra- 
dation, for in the inferior races, such as the Negro and Australian, 
the lower jaw protrudes farther than does that of the superior 
races. But even the perfect, equilateral triangular jaw of modern 
man is being transformed into something different by civilization. 
Darwin in the “ Descent of Man” remarked that “ it appears 
as if the posterior molar or wisdom-teeth were raise to become 
rudimentary in the more civilized races of man.’ 2 
From a careful study of 1,249 skulls, of which 844 were os 
the highly civilized modern races, 277 of modern inferior races, 
and 128 were of the Romans, Etruscans, Phoenicians, and other 
nations of antiquity, Prof. Mantegazza furnishes corroborative 
evidence of this tendency, for he finds that the wisdom teeth are 
more frequently absent in the superior than in the inferior types, 
the percentage of absence being more than twice as great in the 
former as in the latter. He concludes that at a period more 
or less remote the third molar will disappear from the human jaw. 
It has been also observed that the third molar or wisdom 
tooth is smaller than the other molars in man, and the same has 
been found true of the chimpanzee and orang, the apes which 
most closely approximate man. 
In the superior races of man the wisdom teeth frequently re- 
main imperfectly developed beneath the gum, and when they 
emerge early decay, and they have only two separate fangs, 
while in some inferior (Melanian) races these teeth are usually 
sound, and generally have three fangs, thus more nearly 
approaching the typical mammalian third molar. 
This loss of size of the wisdom teeth is due, according to 
Prof. Schaaffhausen, “to the posterior portion of the jaw being 
always shortened in the more civilized because they use soft 
cooked food, and use their jaws less.” 
