L[iheritance of Acquired Characters 231 
experimental test, and it is astonishing to find that, with 
the immense amount that has been written by his followers, 
so few attempts have been made to give the theory a thorough 
test. The few results that have been obtained are not, how- 
ever, favorable to the theory, but almost the only attempts at 
experiment that have been made in this direction have been 
those of mutilating certain parts; and were it not for popu- 
lar belief to the effect that such mutilations are inherited, 
one would least expect to get evidence for or against the 
theory in this direction. Lamarck himself believed that the 
changes were slowly acquired, and I think modern Lamarck- 
ians are justified in claiming that the validity of the theory 
can only be tested by experiments in which the organism is 
subjected to influences extending over a considerable period, 
although Lamarck appears to have believed that the first 
results may appear quite soon. Before expressing any 
opinion in regard to the probability of the theory, let us 
examine what the followers of Lamarck have contributed in 
the way of evidence to the theory, rather than the applica- 
tions that they have made of the theory. We shall also find 
it profitable to consider some of the modern criticism, to which 
the theory has been subjected. 
Despite the contempt with which Darwin referred to 
Lamarck’s theory, he himself, as we have seen, often made 
use of the principle of the inheritance of acquired characters, 
and even employed the same illustrations cited by Lamarck. 
Darwin seems to have misunderstood Lamarck’s view, and 
to have accepted the current opinion that Lamarck sup- 
posed an animal acquired a new organ by desiring or need- 
ing it. Darwin says, ‘‘ Heaven forefend me from Lamarck’s 
nonsense of a tendency to progressive adaptation from 
the slow willing of the animals.” Darwin speaks of La- 
marck as stating that animals will that the egg shall be 
a particular form so as to become attached to particular 
objects. Lamarck’s latest biographer, Packard, says he is 
