HISTORY OF ORGANIC EVOLUTION—-COULTER 321 
doned by some of their descendants. In these days, it has become the 
habit to call these rudimentary structures “ vestiges.” Many such 
illustrations could be given. One in the human body is the vermi- 
form appendix. It seems safe to say that we are walking museums of 
antiquity. 
As technique developed still further, the embryology of plants 
and animals began to be studied in detail, the whole progress from 
egg to adult being observed. In very many cases, during the prog- 
ress, glimpses of fleeting structures and resemblances were obtained, 
which had disappeared when the adult stage was reached, but which 
related the form to other species. 
After this succession of facts, there came a revelation which con- 
vinced more men that evolution is a fact than any evidence which 
had preceded. The geologists had begun to uncover that wonderful 
succession of plants and animals from the earliest geological periods 
to the present time. ‘They saw in the oldest periods forms unlike any 
now existing; they saw gradual changes with each succeeding hori- 
zon; they saw a steady approach to forms like those of to-day. 
until by insensible gradations the present flora and fauna were 
ushered in. This geological record, becoming continuously more 
detailed in its interpretation, set men to thinking seriously. 
Finally, after all this evidence was in, men began to look around 
them and to realize what they had been doing for centuries in 
domesticating animals and plants. They had been bringing them 
from the wild state and changing them so much by the methods of 
culture that in many cases the wild originals could not be recognized. 
Most of our cultivated plants, if found in nature associating with 
their wild originals, would be regarded as extremely distinct species. 
In the presence of such an array of facts, is it to be wondered at 
that certain men began the serious, scientific study of evolution? 
As a result, the second period in the history of evolution was ushered 
in, and evolution became a science. 
(2) Observation and inference.—In time, this period extends from 
1790 to 1900. It is characterized by the appearance of a succession 
of explanations of evolution. It is important to remember that the 
men who offered these explanations are not responsible for the idea 
of evolution, but merely attempted to explain the fact of evolution. 
They were explainers rather than authors. It is also important to 
realize the method used. It may be called the method of comparison 
and inference. Plant and animal forms were observed, and re- 
semblances were assumed to indicate relationship through descent. 
It was not demonstration, but inference based on observation. Dar- 
win carried the method to the limit of its possibilities, observing not 
a small range of forms, but observing through several years a world- 
wide range of forms, in connection with the famous voyage of the 
