ON OUR KNOWLEDGE 



OF THE 



CAUSES OF THE PHENOMENA 



OF 



ORGANIC NA1ITSE 



BEING 



SIX LECTURES TO WORKING MEN, 



DELIVERED AT THE 



MUSEUM OF PRACTICAL GEOLOGY. 



BY 



PROFESSOR HUXLEY, F.R.S. 



LONDON: 

 ROBERT HARDWICKE, 192, PICCADILLY. 



1863. 



