XX. 



RECAPITULATION. 



I will now briefly recapitulate some of the con- 

 clusions reached in the preceding pages. In the first 

 place, I have called attention to some of the chemical 

 properties of matter, showing that the elements act 

 according to definite laws; that in combining they 

 produce compounds, the nature of which could not 

 have been predicted, and that the carbon compounds 

 especially are indefinitely numerous and wonderful in 

 their properties. 



We have seen that the chemist can prepare from 

 the elementary substances certain carbon compounds 

 which are produced by animals .and plants, but that 

 he is not able to produce matter in the organized form, 

 such as protoplasm, in which life manifests itself. 



I next considered energy, or the forces of nature. 

 Energy was defined as being that which can put mat- 

 ter in motion. It was seen that the transmission of 

 energy seems to demand a medium of some kind, and 

 that ether is believed by physicists to be a universally 

 distributed medium. 



The existence of this medium does not explain the 

 action of the force of gravity. 



It is believed that matter and ether fill all space, 

 and that they are in constant motion ; but the inten- 

 sity of their motion varies at different times and in 

 different places. 



The energy stored up in matter is being gradually 



imparted to ether, and unless there is some method 



(330) 



