NOVEMBER, 1905. OECOLOGICAL FEATURES OF EVOLUTION. 
177 
or Onagrathe (Oenothera lamarckiana) . This weed was intro- 
duced into Europe from Virginia in 1613. Introduced into Hol- 
land it soon became acclimated and is cultivated there ; it also 
grows there in a wild and uncultivated state having: escaped from 
gardens. One species the lamarckiana is especially abundant 
about the city of Hilversum. In 1875 it was noticed that in this 
district this species showed unusual vigor and remarkable powers 
of dispersal and multiplied in profusion. 
Here is evidently, a case where a species has found a chance 
to grow to large numbers in a new environment, it has evidently 
found hospitality ; but that the hospitality attained is not abso- 
lute is shown by the fact that the species was in a violent state of 
change, variants being produced in large numbers and indiscrim- 
inately for DeVries notes that many of the varieties are evidently 
less well fitted to survive than the parent. His idea is that the 
mutation is a period of the species life and independent of en- 
vironment but its history shows that it is essentially a migrant 
form in a new environment. He says "ordinarily the principal 
period of mutation is found at the earliest stage of the species, at 
the time of its birth, but this is not absolute. However, the phase, 
or the entire group of phases, of plasticity, is more or less brief in 
comparison with the rest of its existence." This idea Burbank 
denies in that he says it is not a period of the species existence 
but a condition of the species which he claims to be able to pro- 
duce at will. As quoted by Harwood in the April Century, 1905, 
Burbank says: "The life forces are constantly pressing forward to 
obtain any space which can be occupied, and, if they find an open 
avenue, always make use of it as far as heredity permits." His 
idea of DeVries mutation is the disturbance of the life processes 
of a plant by crossing and the resultant confusion of hereditary 
processes, the inertia of the influence of each parent in the off- 
spring in an automatic attempt to produce characters which were 
proper for its own environment resulting in abundant sporting. 
Both have evidently recognized the disturbed condition of the 
environment which Burbank has produced and DeVries dis- 
covered ; the environment of both is changed or changing and 
the species and individual are responding in the abundant var- 
iants. 
The most prominent objection to the explanation by this 
means is that a species in a changed environment does not al- 
ways produce heterogeneous variants but that they some times 
vary toward a definite type, new or atavistic. 
Under the term Vital Principle has been expressed, the idea 
