72 FRAGMENTS OF SCIENCE. 



source, as I have already stated, is the sun. It is the 

 sun that separates the carbon from the oxygen of the 

 carbonic acid, and thus enables them to recombine. 

 Whether they recombine in the furnace of the steam- 

 engine or in the animal body, the origin of the power 

 they produce is the same. In this sense we are all ' souls 

 of fire and children of the sun.' But, as remarked by 

 Helmholtz, we must be content to share our celestial 

 pedigree with the meanest of living things. 



Some estimable persons, here present, very possibly 

 shrink from accepting these statements ; they may be 

 frightened by their apparent tendency towards what is 

 called materialism a word which, to many minds, ex- 

 presses something very dreadful. But it ought to be 

 known and avowed that the physical philosopher, as 

 such, must be a pure materialist. His enquiries deal 

 with matter and force, and with them alone. And 

 whatever be the forms which matter and force assume, 

 whether in the organic world or the inorganic, whether 

 in the coal-beds and forests of the earth, or in the brains 

 and muscles of men, the physical philosopher will make 

 good his right to investigate them. It is perfectly vain 

 to attempt to stop enquiry in this direction. Depend 

 upon it, if a chemist by bringing the proper materials 

 together, in a retort or crucible, could make a baby, he 

 would do it. There is no law, moral or physical, for- 

 bidding him to do it. At the present moment there 

 are, no doubt, persons experimenting on the possibility 

 of producing what we call life out of inorganic materials. 

 Let them pursue their studies in peace ; it is only by 

 such trials that they will learn the limits of their 

 own powers and the operation of the laws of matter and 

 force. 



But while thus making the largest demand for free- 

 dom of investigation while I consider science to be 



