MUTATION IN ENOTHERA 145 
formation of the pollen was very defective. None of 
the others was lacking in either of these respects. Each 
new form was distinguished by certain definite features 
which affected almost all its parts, not by one new 
character only; and these features were never separable, 
but always appeared in common on the same plant. 
The new species, of course, showed normal fluctuat- 
ing variability, and, as an extreme result of this varia- 
bility, forms occasionally appeared midway between 
one of the new species and the parental type. In such 
cases, when the self-fertilized seed of the plant showing 
such an intermediate character was sown, the offspring 
were found to group themselves round the normal 
form of the new species oy round that of the parent 
Lamarckiana, thus affording evidence as to the true 
nature of their parent. 
Whether or not we are prepared to accept the whole 
of de Vries’ conclusions from his experiments, we can 
see at least that from one point of view they are of the 
very greatest importance. For before de Vries pub- 
lished this work it had been supposed to be quite im- 
possible to make direct observations upon the manner 
of origin of new species in Nature. De Vries has now 
shown that such observations can be made, and this 
is in itself a most valuable piece of information. He 
has introduced an entirely new method into the domain 
of species research, and one by the use of which it is 
to be hoped that before long a definite answer will be 
obtained to the question whether species in general 
arise by definite steps, or with an imperceptible degree 
of slowness. 
Bae) 
