EVOLUTION OF INSTINCTIVE BEHAVIOUR 109 
action; instinct, as inherited habitual voluntary action, or 
the capacity for such action.” 
Turning now to the opposite end of the scale of opinion, 
we find that Professor Weismann, commenting on the supposed 
inheritance of acquired habit, says,* “I believe that this is an 
entirely erroneous view, and I hold that all instinct is entirely 
due to the operation of natural selection, and has its founda- 
tion, not upon inherited experiences, but upon variation of 
the germ.” Ziegler and Groos in Germany, Whitman and 
Baldwin in America, Poulton and Wallace in England, either 
deny the existence of secondary instincts, due to the inheritance 
of acquired habits, or question the sufficiency of the evidence 
adduced in support of such transmission. In their explanation 
of the manner in which that inherited co-ordination, which is 
biologically the central fact in instinctive behaviour, has been 
evolved they rely mainly or entirely on the principle of natural 
selection. 
What, then, were the facts which appeared to Romanes 
sufficient to justify a belief in the existence of a class of 
instincts dependent on inherited habit for their origin? He 
tells us that he only gives a few examples “amongst almost 
any number” that he could quote. It is certainly unfortunate 
that, out of more than one hundred and fifty pages devoted to 
instinct in his work on “ Mental Evolution in Animals,” only 
three ¢ are assigned to secondary instincts ; or six, if we include 
one dealing with inherited peculiarities of hand-writing in 
_man, and two showing the force of heredity in the domain 
of instinct, “ whether of the primary or secondary class.” It 
is true that many pages are devoted to instincts of blended 
origin, but the co-operation of the Lamarckian factor is here 
rather assumed than proved. We must, however, be content 
to take the few examples that are actually given. They are 
four in number. First, that ponies in Norway are used with- 
out bridles, and are trained to obey the voice; and that, as 
a consequence, a race-peculiarity has been established, for 
* « Hssays on Heredity ” (1889), p. 91. 
¢ Op. cit, pp. 196-198. 
