54 EVOLUTION AND THE 
ov 
pendent elemental mode of origin. Thus, living 
matter may have been continually coming into being 
all over the surface of. the Earth ever since the time 
of man’s first appearance upon it, and yet the 
fact that no member of the human race has ever 
“seen (or is ever likely to see) such birth, throws 
even no shade of doubt upon the probability of 
its occurrence. 
What then becomes of the supposed validity of this 
much respected phrase, omne vivum ex vivo? No 
more requires to be said than that it is an instance 
of one of those rude and loose inductions, common 
amongst the uneducated, and in early days even 
amongst scientific men. As the late Mr. Mill* 
said :— The unprompted tendency of the mind is 
to generalize its experience, provided this points all 
in one direction ; providing no other experience of a 
conflicting character comes unsought. The notion of 
seeking it, of experimenting for it, of dzterrogating 
Nature (to use Bacon’s expression) is of much later 
growth. The observation of nature by uncultivated 
intellects is purely passive; they accept the facts 
which present themselves, without taking the trouble 
of searching for more.... But though we have 
always a propensity to generalize from unvarying 
experience, we are not always warranted in doing so, 
* System of Logic, 6th edit., vol. i., p. 349. 
