SCIENTIFIC MATERIALISM. 405 
You will notice that I am stating the truth strongly, as 
at the beginning we agreed it should be stated. But I 
must go still further, and affirm that in the eye of science 
the animal body is just as much the product of molecular 
force as the chalk and the ear of corn, or as the crystal of 
salt or sugar. Many of the parts of the body are obviously 
mechanical. Take the human heart, for example, with its 
system of valves, or take the exquisite mechanism of the 
eye or hand. Animal heat, moreover, is the same in kind 
as the heat of a fire, being produced by the same chemical 
process. Animal motion, too, is as certainly derived from 
the food of the animal, as the motion of Trevethyck's 
walking-engine from the fuel in its furnace. As regards 
matter, the animal body creates nothing; as regards force, 
it creates nothing. Which of you by taking thought can 
add one cubit to his stature? All that has been said, then, 
regarding the plant, may be restated with regard to the 
animal. Every particle that enters into the composition 
of a nerve, a muscle, or a bone has been placed in its posi- 
tion by molecular force. And unless the existence of law 
in these matters be denied, and the element of caprice in- 
troduced, we must conclude that, given the relation of any 
molecule of the body to its environment, its position in the 
body might be determined mathematically. Our difficulty 
is not with the quality of the problem, but with its com* 
plexiiy; and this difficulty might be met by the simple 
expansion of the faculties we now possess. Given this 
expansion, with the necessary molecular data, and the chick 
might be deduced as rigorously and as logically from the 
egg, as the existence of Neptune from the disturbances of 
Uranus, or as conical refraction from the undulatory theory 
of light. 
You see I am not mincing matters, but avowing nakedly 
what many scientific thinkers more or less distinctly believe. 
The formation of a crystal, a plant, or an animal, is, in 
their eyes, a purely mechanical problem, which differs from 
the problems of ordinary mechanics, in the smailness of 
the masses, and the complexity of the processes involved. 
Here you have one half of our dual truth; let us now 
glance at the other half. Associated with this wonderful 
mechanism of the animal body we have phenomena no less 
certain than those of physics, but between which and the 
mechanism we discern no necessary connection,, A man, 
