CHAPTER XXXIII 
EXPERIMENTAL EVOLUTION 
445. A New Method of Study. Previous to Darwin's 
time the study of plants and animals, was carried on 
chiefly by observations in the field. The science was 
largely descriptive a record of what men had observed 
under conditions over which they did not endeavor to 
exercise any control; it was accurately named "Natural 
History" a description of Nature. But Darwin and a 
few of his contemporaries, especially among botanists, be- 
gan to make observations under conditions which they 
determined and largely regulated. In this way the 
problems were simplified, observation became more ac- 
curate, and the endeavor was made to assign the prob- 
able causes of the observed phenomena. With the intro- 
duction of this experimental method, science began to make 
rapid strides, and, more than ever before, facts began to 
be, not only recorded; but interpreted and explained. 
446. Hugo de Vries. The director of the Botanic Gar- 
den in Amsterdam, Holland, Hugo de Vries, was among 
the first to demonstrate that the method of experiment 
may be applied to the study of evolution. His plan was 
to secure seed of a given species from a plant which he 
'believed to be pure with reference to a given character, 
that is, not contaminated or mixed by being cross-pollin- 
ated with another variety or species. The characters of 
the parent plant were carefully noted and recorded by 
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