228 The American Naturalist. [March, 
To discover that the human jaw and teeth are so perfect an 
instrument that human ingenuity cannot conceive of any improve- 
ment, but must crudely imitate the pattern nature furnishes when 
artificial assistance is needed, is no exception; is it not the same 
with the human eye, the ear, the hand, the foot? A manufac- 
turer of artificial legs might with equal justice claim that he has 
discovered that the line of junction of the human foot to the leg 
was a right angle; that all races have it, and that it has so ex- 
isted from the advent of the first man; that it belongs exclu- 
sively to man; that a right angle is the quarter of a perfect 
circle, and the only angle which will equally divide both a circle 
and a half circle; that consequently the human foot was a special 
creation, and could not have been evolved from something lower, 
and could not have been evolved into something higher ; that he 
had made an artificial leg, which performed all the functions of 
the natural one, even to the complex movements of the ankle- 
joint, so perfectly as to deceive all beholders ; that—ad infinitum 
et ad 
Is it not already evident that such a line of reasoning may lead 
one to the most absurd conclusions ? 
There is one other question which has no direct bearing upon 
the argument from the teeth, but which I notice because Dr. 
Bonwill makes so much ofit. He claims that since according to 
the first law of motion a body once set in motion will continue 
to move in a straight line forever unless deflected by surrounding 
bodies, and made to describe an orbit; and as no world ever did 
go in a straight line, but began at once to move in a circle or 
ellipse, “it is plain that it never began the universe by making 
one world at a time and throwing it into space, it being absolutely 
necessary that there should be at least three worlds in order to 
counterbalance each other, and make the first law of motion a fact.” 
There are some arguments which, like a two-edged sword, cut 
both ways. If such a condition of things be true, I would like an 
explanation of the first chapter of Genesis, which both Dr. Bonwill 
and I believe, where we are told that the Lord created the earth, 
gave it globular form, made dry land appear, and vegetation grow, 
for three days before the sun, moon and stars werecalled forth. 


