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THE POPULAR SCIENCE MONTHLY. 



applied the learning of Aristotle to his practice of medicine. 

 Man, he said, is but matter containing certain properties. If 

 these properties be in correct proportion, well and good ; but if 

 the balance be upset, sickness results. The therapeutics of Galen 

 consisted, therefore, in restoring the lost property. If the patient 

 had a chill, he put him in a warm bath ; if he had a fever, he put 

 him in a cold bath. 



Van Helmont, whose work belongs chiefly to the first half of 

 the seventeenth century, tells us of the existence of an Archeeus, 

 and in this theory he was supported by Paracelsus. The Archseus 

 was a spirit which had its abode in the stomach of man. If the 

 Archseus were well nourished, he was pleased and happy ; but if 

 anything disagreeable reached him, he made his displeasure pain- 

 fully evident, and if something were not done to appease his 

 anger, he betook himself off, arid the man was dead. 



Our present views are entirely different. Properties are not 

 separable from matter. Properties are inherent in matter. Upon 

 this knowledge our modern opinions are based. We have spoken 

 of a belief that life depended on a property a "vital force." 

 A "force" may be defined as something that can not be ex- 

 plained. The laws of gravitation stand as Newton left them, but 

 what the force of gravitation is no man can say. Hence, the 

 expression " vital force " was but a confession of ignorance. No, 

 there is no such thing as a " vital force." There are in living Na- 

 ture and in the inanimate world the same materials, ruled in both 

 cases by the same natural chemical and physical laws, only the 

 conditions in living Nature are different from the conditions in 

 the inanimate, and consequently the phenomena observed are like- 

 wise different. 



Let us now look at some of the discoveries which have caused 

 us to accept this material view of life. 



Harvey, in 1616, first taught the true doctrine regarding the 

 circulation of the blood, and compared the heart to a pump. 



Scheiner, a Jesuit priest, declared the action of the eye to be 

 like that of a camera obscura, the lens of the eye acting to form a 

 picture on a background. 



Keppler developed the theory of spectacles. 



Borelli explained how the mechanism of breathing was due to 

 the elasticity of the lungs and to the muscles acting as power 

 upon levers the ribs. 



Lavoisier showed that animal heat was due to the decomposi- 

 tion of higher chemical compounds of the food eaten, just as the 

 heat of the candle is produced by the combustion of its constitu- 

 ents. 



All these facts are easily seen to be but followings after Na- 

 ture's laws. Chemistry brings many proofs confirming the doc 





