68 
of horticulture, and gathering. up the records of the introduction, 
from time to time, of new species and varieties ; second, by closely 
scanning wild plants for the discovery of probably mutating 
forms ; and third, by laborious and long-continued test cultures 
of plants, for the purpose of detecting mutations and of determin- 
ing the laws of heredity and variation. In each of these fields, 
he has been eminently successful. He has shown that in times 
past, new varieties and species have without doubt sprung into 
existence unobserved. He has discovered wild plants with their 
mutants growing beside them. He has raised hundreds of species 
in his garden and actually beheld new species spring from them, 
and he has followed seedlings and cuttings through generation 
after generation, until he has disclosed many of the laws govern- 
ing the transmission of their characters 
While throwing light upon the question of the relative impor- 
ance of heredity and environment, he has, in large measure, 
cleared up the confusion which has long existed with reference 
to the meanings and connotations of the terms ‘‘species”’ and 
‘‘varieties.’’ His pedigree cultures and extended observations 
have quite satisfactorily confirmed the theory that the characters 
which we regard as varietal, specific and generic, are fundamen- 
tally elecurey in their nature, and he has furnished evidence 
in confirmation of Mendel’s law, and in consonance with the most 
important ene of modern cytology. He pays Darwin the 
compliment of saying that he has based his field researches and 
his testing of native plants on the idea of unit-characters deduced 
from Darwin’s hypothesis of pangenesis. In many directions de 
Vries has moved forward of Darwin’s positions, +4 let us admit, 
on the line of Darwin’s own advances over his predecessors. 
pre 
Their work is really continuous, as de Vries himself generously 
declares. 
The most striking of his discoveries are those relating to the 
evening primroses, by which he has demonstrated for the first 
time that a new and veritable species may descend by a single 
step from a parent species. Under his very eye Onagra Lamarc- 
kiana gave birth to over a dozen novel forms, most of which are 
entitled to be ranked as species, although a few are considered 
