54 BAILEY—MOVEMENT IN PLANT-BREEDING. [April 2, 
3. The nitrogen and sulphur constituents of petroleum could 
only have been formed directly from or through the agency of 
animal organic matter. 
There is an attractive field for the chemical geologist to study, 
more intimately than has ever been done, the occurrence of petro- 
leum in connection with its composition. 
CLEVELAND, O. 
THE FORWARD MOVEMENT IN PLANT-BREEDING. 
BY L. H. BAILEY. 
(Read April 2, 1903.) 
The first specific interest in cultivated plants was in the gross 
kinds or species. As the contact with plants became more inti- 
mate, various indefinite form-groups were recognized within the 
limits of the species. Gradually, with the intensifying of domes- 
tication and cultivation, very particular groups appeared and were 
recognized. These smaller groups came finally to be designated 
by names, and the idea of the definite and homogeneous cultural 
variety came into existence. The variety-conception is really a 
late one in the development of the human race. It is practically 
only within the past two centuries that cultivated varieties of plants 
have been recognized as being worthy of receiving designative 
names. It is within this period, also, that most of the great breeds 
of animals have been defined and separately named. 
All this measures the increasing intimacy of our contact with 
domesticated plants and animals. It is a record of our progress. 
The peoples that are most advanced in the cultivation of any plant 
are the ones that have the most named varieties of that plant. In 
Japan, to this day, the plums pass under ill-defined class-names. 
We have introduced these classes, have sorted out. the particular 
forms that promise to be of value to us and have given them 
specific American names. Not long ago a native professor in 
Japan wrote me asking for cions of these plums,*in order that he 
might introduce Japanese plums into Japan. ‘The Russian apples 
are designated to some extent by class-names; im fact, it was not 
until the appearance of .Regel’s work, about a generation ago, 
that Russian pomology may bé said to have been born. What 
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