1890.] The Teeth as Evidence of Evolution. 227 
He claims, and he puts it in italics, “ Z claim to have discovered 
that the lower jaw of man is an equilateral triangle, and that all 
races have it, and that it has so existed from the advent of the first 
man.” Also, “that it belongs exclusively to man.” He claims 
that as an equilateral triangle in a hexagon is the equal of a 
circle, and as a circle is the embodiment of perfection of form, it 
is a natural deduction that the human jaw cannot be evolved 
higher or a more perfect form conceived. Such is the discovery 
which he has made and which he classes with the law of gravita- 
tion, a claim, to say the least, which cannot be characterized as 
modest. 
I will give his own words: “I claim that as Newton discovered 
that geometry and mechanics governed the formation and action 
of the astronomical worlds, I have an equal right to the discovery 
of the relation of the same laws to the structural organic world.” 
If the human jaw be the perfect instrument claimed for it, and 
beyond the reach of further evolution, this would not, as he holds, 
prevent the contrary hypothesis ; that it is the end towards which 
nature has tended by evolution through successive forms of life, 
from the simpler to the more complex. 
That the human jaw is an equilateral triangle is an interesting 
anatomical observation, and Dr. Bonwill, if he is the first to 
notice it, should have all credit for discovering the fact; and 
_ that the teeth are perfect in position and adaptibility to their 
intended purpose, goes without saying. But to stop to even 
enumerate all the observations bearing upon the relation of the 
various organs to the principles of geometry and mechanics 
would tire the reader, and the evolutionist of all people would be 
the last to deny the perfect adaptability of the organs to their 
destined use, for it is this they bring in evidence as to the truth 
of evolution. 
The intimate relation of the eye to optics, of the ear to acous- 
tics, of the lungs to pneumatics, of the heart to hydraulics, of the 
digestive organs to chemistry, and the attachments of muscles to 
bones to the physics of levers, are familiar to every student of 
anatomy and physiology. 
