1903.] BAILEY—MOVEMENT IN PLANT-BREEDING. 55 
constitutes a variety is increasingly more difficult to define, because 
we are constantly differentiating on smaller points. The growth 
of the variety-conception is really the growth of the power of 
analysis. 
The earlier recognized varieties seem to have come into exist- 
ence unchallenged. There is very little record of inquiry as to 
how or why or even where they originated. That is, the quest of 
the origin arose long after the recognition of the variety as a 
variety. Even after inquisitive search into origins had begun 
there was little effort to produce these varieties. The describing of 
varieties and the search into their histories was a special work of 
the nineteenth century. One has only to consult such American 
works as Downing’s Fruzts and Fruit Trees of America and Burr’s 
field and Garden Vegetables of America, te see how carefully and 
methodically the descriptions and synonymy of the varieties were 
worked out. These are types of excellent pieces of editorial and 
formal systematic work. 
There have been isolated efforts at producing varieties for many 
years. These efforts began before the time of the general dis- 
cussion of organic evolution. In fact, it was on such experiments 
that Darwin drew heavily in some of his most important writings. 
Roughly speaking, however, the conception that the kinds of 
plants can be definitely modified and varied by man is a product of 
the last half century. We now believe that there is such a possi- 
bility as plant-breeding. It is really a more modern conception, 
so far as its general acceptance is concerned, than animal-breeding. 
But both animal-breeding and plant-breeding are the results of a 
new attitude toward the forms of life—a conviction that the very 
structure, habits and attributes are amenable to change and control 
by man. This is really one of the great new attitudes of the mod- 
ern world. 
Formerly, and even up to the present time, the variety has been 
taken as the unit for plant-breeding work, as it has been for 
descriptive and classificatory work. Whether we believed it or not, 
we have accepted it as a fairly definite thing or entity. Yet, what 
is a variety? Only the ideal of one man or a set of men. 
Custom may define its boundaries, but in fact it has no boundaries. 
At best, a variety is only an assemblage of forms that agree rather 
more than they differ: and any one of these forms may, with equal 
propriety, be called another variety. Shall we continue to 
