An Introduction to a Biology 



It is true that Descartes endowed the human 

 body with a soul ; but it is probable that he did 

 this to avoid trouble with the ecclesiastical author- 

 ities. His placing of the soul was a pleasant fancy ; 

 he put it in the pineal body because that was the 

 only unpaired structure in the brain, and he called 

 the two diverging strands of nervous tissue which 

 extend downwards from this body the habenulce, 

 and thus gave the picture of the soul as a coach- 

 man, perched up on his box, with his reins between 

 his fingers, driving with a cheerful confidence that 

 restive team, the human body. 



But to the non-human animal Descartes did 

 not vouchsafe a soul. The orgy of vivisection which 

 followed the enunciation of the mechanistic con- 

 ception of the organism was justified by those who 

 took part in it on the ground that the cries of their 

 victims were no more than the sounds produced by 

 the disruption of machinery. The difference between 

 the noise produced by kicking a dog and kicking 

 a tin can, according to such men, is due to the differ- 

 ence between the structure of the dog and the con- 

 formation of the can. But the cause of the noise 

 in the two cases was the same, the application of 

 the requisite stimulus to an arrangement of material 

 particles ; whether such arrangement take the simple 

 form, of a tin can, or assume that complexity of 

 structure which is found in the familiar mechanism 

 to which we are accustomed to apply the name of 

 dog. 



Modern Biology, the lineal descendant of, and 

 so personally identical with, the mechanistic con- 

 ception let loose by Descartes about two centuries 



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