II4 THE HISTORY OF CREATION. 
violent cataclysmic revolutions ; and in general the incon- 
ceivableness of any miracle, of any supernatural interference, 
in the natural course of the development of matter. 
The fact that Lamarck’s wonderful intellectual feat met 
with scarcely any recognition, arises partly from the im- 
mense length of the gigantic stride with which he had 
advanced beyond the next fifty years, partly from its 
defective empirical foundation, and from the somewhat one- 
sided character of some of his arguments. Lamarck quite 
correctly recognizes Adaptation as the first mechanical 
cause which effects the continual transformation of organic 
forms, while he traces with equal justice the similarity 
in form of different species, genera, families, ete, to their 
blood-relationship, and thus explains it by Inheritance. 
Adaptation, according to him, consists in this, that the per- 
petual, slow change of the outer world causes a corre- 
sponding change in the actions of organisms, and thereby 
also causes a further change in their forms. He lays the 
greatest stress upon the effect of habit upon the use and 
disuse of organs. This is certainly of great importance 
in the transformation of organic forms, as we shall see 
later. However, the way in which Lamarck wished to 
explain exclusively, or at any rate mainly, the change of 
forms, is after all in most cases not possible. He says, for 
example, that the long neck of the giraffe has arisen from its 
constantly stretching out its neck at high trees, and from 
the endeavour to pick the leaves off their branches; as 
giraffes generally inhabit dry districts, where only the 
foliage of trees afford them nourishment, they were forced 
to this action. In like manner the long tongues of wood- 
peckers, humming-birds, and ant-eaters, are said by him to 
