140 CANNON: STUDIES IN PLANT HypBrips 
In considering the probable bearing of Mendel’s discovery on 
the biological sciences I can do no better than to quote at some 
length from Bateson’s recent report, but of course I shall not at- 
tempt to present a summary of all of this author’s conclusions. 
Bateson says (/. c. 125): “ With the discovery of the Mendelian 
principle the problem of evolution passes into a new phase. It 
is scarcely possible to overrate the importance of this discovery. 
Every conception cf biology which involves a knowledge of the 
physiology of reproduction must feel the influence of the new facts, 
and, in their light, previous ideas of heredity and variation, the 
nature of specific differences, and all that depends on those ideas 
must be reconsidered, and in a great measure modified.” 
So much for the scope of the Mendelian principle. Bateson 
then cites specific examples, well known to breeders and scientists, 
which have hitherto been puzzling enough but which are appar- 
ently well explained by the discoveries of Mendel. Among these 
may be mentioned (1) the skipping of a generation, (2) the appear- 
ance in a pure strain of ‘‘ rogues,” and (3) the inability of breeders 
to fix by selection certain forms. The first is an integral part of 
the Mendelian conception and therefore need not be spoken of 
further here. The ‘rogues’? which appear in apparently pure 
strains are supposed to be recessives, while in such instances the 
characters desirable for fixation are the dominant ones. And the 
-last case will be best explained by the author himself. At page 
131 he says: “It has long been known to breeders that certain 
forms cannot be fixed by selection indefinitely continued. In other 
words, though they produce offspring like themselves, they have 
_also a large number which do not resemble them. 
‘A case of this kind is seen in breeding crested canaries. The 
kind of crest desired for exhibition can, according to canary-fan- 
ciers, be produced most easily by mating crested birds with non- 
crested, or plain heads as they are called. If it is supposed that 
the crested character is usually dominant, we have a simple expla- 
nation. When crested birds are bred together a number of birds 
are produced whose crests are coarse and stand up and others 
without crests. The latter are the recessives ; the former we may 
suppose to be the pure dominants. What the fancier wants is a 
crest composed of long feathers lying evenly down over the head. 
