28 EVOLUTION AND THE 
Much stress is laid by certain writers upon the fact 
that “the doctrine of spontaneous or equivocal gene- 
ration has been chased successively to lower and 
lower stations in the world of organized beings as 
our means of investigation have improved.”* So 
that, as another very eminent writer says, “if some 
apparent exceptions still exist they are of the lowest 
and simplest forms.” And it is usually inferred 
from this fact that further knowledge and improved 
means of observation will prove these apparent ex- 
ceptions to be no exceptions to the supposed general 
rule—ommne vivum ex vivo. A consideration of this 
kind seems to have powerfully influenced Professor 
Huxley. 
Much confusion exists in reference to this point, 
which needs to be removed. In the first place, it 
must be freely admitted that many ancient notions, 
dating from the time of Aristotle, on the subject of 
“Equivocal or Spontaneous Generation,” as a mode 
of origin for large and complex organisms, were 
altogether crude and absurd. Secondly, it is neces- 
sary to distinguish (and Professor Huxley did so) 
between two meanings of the phrase which have 
often been confounded with one another—viz., be- 
* Prof. Lister, Introductory Lecture (University of Edinburgh), 
1869, p. 12. . 
+ Mr. Justice Grove (Presidential Address), Rep. of Brit. Assoc. for 
the Advancement of Science, 1866, p. 71. 
