ORIGIN OF LIFE. 45 
he might have found that the supposed impossibility 
of conception was entirely delusive. Again, it is 
well known that Professor Huxley did at the time 
discredit the now admitted fact that Bacteria will 
appear in sealed flasks (containing suitable fluids) 
whose air has been expelled by boiling.* He dis- 
credited this fact because he believed that Bacteria 
must have been destroyed by the process of boiling 
—and because he was unwilling to believe that they 
could be produced de zovoe. He went, as we have 
seen, so far as to say that he would rather discredit 
scientific evidence concerning the destructive influence 
of heat upon living matter, than believe in the present 
occurrence of a life-evolution similar to that which 
he postulates for the past—although he is quite unable 
to assign any valid reason for making such a distinction 
between present evolutional potentialities and those 
assumed to exist in an unknown past. 
What then has been the subsequent progress of | 
events? In the first place it has been shown by 
Professor Burdon Sanderson, myself, and others, that \ 
living Bacteria germs are not diffused through the i 
air to any appreciable extent,f and this is now a very \ 
widely accepted doctrine, in spite of its being, as 
Professor Huxley imagined, an impossible conception. 
* Nature, Sep. 15, 1870, p. 403. 
+ Beginnings of Life, 1872, vol. ii. p. 6. 
