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conditions of environment in which they lived. They did not die 
before their time, overcome by the mythical fittest who are said to 
survive in the struggle. They were the fittest, and died natural deaths, 
having provided before they gave up the struggle for their progeny to 
succeed them. The hard parts record the history of adults which have 
endured the struggle, and thus represent the royal line of succession 
for the geological ages.”’ 
Evolution is a fundamental law in the geological history of organ- 
isms. The “morphological differentiation (evo/wfion) is as characteristic 
of the history of organisms in geological time as organic growth 
(development) is characteristic of the history of the individual organ- 
ism in its lifetime.” With the progress of time the morphological 
characters assumed by organisms have been gradually and incessantly 
changing from the beginning. ‘This constant change or evolution isa 
- fundamental law of organisms. Inorganic things on the contrary are 
unchangeable. The chemical composition and properties of things are 
the same as far back as we can trace them. A quartz crystal formed 
in Archean time has exactly the same form with exactly the same 
angles as a crystal of the same substance formed today. 
A certain analogy between ontogenesis and phylogenesis is com- 
monly recognized. As each individual has a life history, so also has 
each species, genus, family, etc., but this fact must be emphasized, that 
in the individual development a change of function is associated with 
the several stages of ontogenesis; while it is difficult to imagine any 
corresponding change of function in the successive representatives of 
a common race. For this reason great caution is necessary not to force 
the theory of correspondence between the ontogenetic stages of 
functional activity and the order of differentiation of new characters 
expressed in the phylogenetic history of organisms. The two series of 
phenomena present this marked contrast, that in ontogenesis each 
phase of development is a repetition of phenomena which have been 
repeated in the same way from the beginning of organic life, while 
in phylogenesis each step is a step in advance of anything that has 
occurred before. 
Evolution and adaption are both observed facts. The continuous 
morphological change of organisms, codrdinate with the progress of 
time, is evolution. In this onward progress of organisms they are 
everywhere locally adapted to the particular environment in which 
they are placed. This adaptation to environment is brought about 
