156 FRAGMENTS OF SCIENCE. 



But Descartes deviated strangely from the idealism 

 implied in his fundamental principle. He was the 

 first to reduce, in a manner eminently capable of bearing 

 the test of mental presentation, vital phenomena to 

 purely mechanical principles. Through fear or love, 

 Descartes was a good churchman ; he accordingly re- 

 jected the notion of an atom, because it was absurd to 

 suppose that God, if He so pleased, could not divide an 

 atom ; he puts in the place of the atoms small round 

 particles, and light splinters, out of which he builds the 

 organism. He sketches with marvellous physical insight 

 a machine, with water for its motive power, which shall 

 illustrate vital actions. He has made clear to his mind 

 that such a machine would be competent to carry on 

 the processes of digestion, nutrition, growth, respiration, 

 and the beating of the heart. It would be competent 

 to accept impressions from the external sense, to store 

 them up in imagination and memory, to go through the 

 internal movements of the appetites and passions, and 

 the external movements of the limbs. He deduces 

 these functions of his machine from the mere arrange- 

 ments of its organs, as the movement of a clock, or 

 other automaton, is deduced from its weights and wheels. 

 * As far as these functions are concerned,' he says, ' it is 

 not necessary to conceive any other vegetative or sen- 

 sitive soul, nor any other principle of motion or of life, 

 than the blood and the spirits agitated by the fire which 

 burns continually in the heart, and which is in nowise 

 different from the fires existing in inanimate bodies.' 

 Had Descartes been acquainted with the steam-engine, 

 he would have taken it, instead of a fall of water, as 

 his motive power. He would have shown the perfect 

 analogy which exists between the oxidation of the food 

 in the body, and that of the coal in the furnace. ^ He 

 would assuredly have anticipated Mayer in calling the 



