CHARLES DARWIN 309 



of the heart as a central pump (1628), long after water pumps 

 with pipes had become quite familiar, while the ideas 

 current concerning the heart and the veins had remained 

 confused and unclear.^ This shows how slow was the 

 progress in the investigation of living things. 



This example also tells us that people were for a long time 

 disinclined to apply experience gained with non-living things 

 to living. It has always been an unmistakable fact that the 

 living creature has something peculiar to itself, which in 

 human beings and the higher animals is so obvious in the 

 form of freedom of will, and that this is wanting in the case 

 of the non-living. The peculiar difference was no doubt 

 accounted for by assuming the two worlds, the living and the 

 non-living to be totally different from one another, and no 

 one was willing to imagine that the same laws of nature could 

 hold for both. In a similar way, there was a reluctance to 

 assume the same laws of motion for celestial and terrestrial 

 bodies, until Newton was able to prove beyond doubt that 

 these laws really are the same. We have already shown, in 

 treating of the age which followed Newton, that the revela- 

 tion of this fact soon led to spurious 'enlightenment,' and 

 accordingly, living things were now regarded, quite in con- 

 trast to earlier times, as pure mechanisms, of the same 

 nature as non-living things; although it was not known 

 whether really all non-living things were pure mechanism, 

 such as were known from the investigation of material bodies. 



At that time, the physics of the ether was only, as a result 

 of Huygens' work, in its initial stages; nevertheless it was 

 right, since in any case necessary, first to get to know from all 

 sides the bodily machine of living things, and to investigate 



1 See the Works of William Harvey, London, 1847, particularly chapter 

 &,. page 45. Harvey, the physician, also gave expression to the fact that 

 every animal has its origin in some egg-like structure (omne animal ex ovo). 

 The sexual reproduction of plants and the mechanism by which this 

 is effected, was only satisfactorily determined about sixty years later 

 (Camerarius in Tubingen, 1694). 



