SCIENTIFIC MATERIALISM. 117 



Now there is nothing in this process which necessarily 

 eludes the conceptive or imagining power of the purely 

 human mind. An intellect the same in kind as our own 

 would, if only sufficiently expanded, be able to follow the 

 whole process from beginning to end. It would see every 

 molecule placed in its position by the specific attractions 

 and repulsions exerted between it and other molecules, the 

 whole process and its consummation being an instance of 

 the play of molecular force. Given the grain and its envi- 

 ronment, the purely human intellect might, if sufficiently 

 expanded, trace out a priori every step of the process of 

 growth, and by the application of purely mechanical prin- 

 ciples demonstrate that the cycle must end, as it is seen to 

 end, in the reproduction of forms like that with which it 

 began. A similar necessity rules here to that which rules 

 the planets in their circuits round the sun. 



You will notice that I am stating my truth strongby, 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 stalk and 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 directly derived from 

 the food of the animal, as the motion of Trevethyck's walk- 

 ing-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, regard- 

 ing the plant may be restated with regard to the animal. 

 Every particle that enters into the composition of a muscle, 

 a nerve, or a bone, has been placed in its position by mo- 



