18 EVOLUTION AND THE 
would Professor Tyndall have us believe that it is 
in any essential way different from that process of 
growth which may take place in a second, third, or 
fourth increment of time? Does not the very fact 
that origination and growth so often occur simulta- 
neously in the case of crystalline matter, and under 
the influence of the same causes, show us that the 
two processes are intrinsically similar, and that con- 
ditions favourable for growth are also likely to be 
favourable for origination? And if this be true for 
crystalline matter, may we not infer that it would 
also be true for living matter? These are questions 
neither asked nor answered in any definite manner 
by those whose opinions I have already cited. They 
are, however, questions by no means unworthy of an 
attentive consideration. 
Although, as a general rule, conditions favourable 
for the growth of any particular kind of crystalline 
matter are likely to be favourable for its origination, 
still it must be acknowledged that the presence of 
a crystal will occasionally lead to its growth in a 
medium in which similar crystalline matter had 
previously shown no tendency to form independently 
—even in cases where the introduction of a non- 
crystalline nucleus would not be able to determine 
a similar formation of crystalline matter. Notwith- 
standing the general law, ,therefore, that conditions 
