460 FRAGMENTS OF SCIENCE. 



functions of his machine from the mere arrangements 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 sensitive 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 blood which the heart diffuses, "the oil of 

 the lamp of life," deducing all animal motions from the 

 combustion of this oil, as the motions of a steam-engine 

 are deduced from the combustion of its coal. As the 

 matter stands, however, and considering the circum- 

 stances of the time, the boldness, clearness, and precision, 

 with which Descartes grasped the problem of vital dynam- 

 ics constitute a marvelous illustration of intellectual 

 power.* 



During the middle ages the doctrine of atoms had to all 

 appearance vanished from discussion. It probably held its 

 ground among sober-minded and thoughtful men, though 

 neither the church nor the world was prepared to hear of 

 it with tolerance. Once, in the year 1348, it received 

 distinct expression. But retractation by compulsion im- 

 mediately followed; and, thus discouraged, it slumbered 

 till the seventeenth century, when it was revived by a 

 contemporary and friend of Hobbes of Malmesbury, the 

 orthodox Catholic provost of Digne, Gassendi. But, 

 before stating his relation to the Epicurean doctrine, it 

 will be well to say a few words on the effect, as regards 

 science, of the general introduction of monotheism among 

 European nations. 



"Were men," says Hume, " led into the apprehension 

 of invisible intelligent power by contemplation of the 

 works of Nature, they could never possibly entertain any 



*See Huxley's admirable "Essay on Descartes." "Lay Sermons," 

 pp. 364, 365. 



