The Fact and. Philosophy of Variation 9 



importance of the individual plant, rather than the im- 

 portance of the species ; for thereby we put ourselves as 

 nearly as possible in sympathetic attitude with nature, and, 

 resting upon the ultimate object of her concern, we are 

 able to understand what may be conceived to be her motive 

 in working out the problem of life. Recall the fact that 

 the whole tendency of contemporary civilization, in soci- 

 ology and religion, is to deal with the individual person 

 and not with the mass. The present-day method of study- 

 ing the evolution of plants and animals is essentially an- 

 alytical. As the chemist attempts to discover the smallest 

 units from which the substances of nature have been built 

 up, so the student of biology and evolution is seeking for 

 the smallest heritable units of which plants and animals 

 are composed. This is only an unconscious feeling after 

 natural methods of solving the most complex of problems, 

 for it is exactly the means to which every organic thing 

 has been subjected from the beginning. 



Conception of unit-characters. The student of evolution 

 now conceives animals and plants to be composed of what 

 he terms " unit-characters," analogous, roughly, to the 

 atoms of the chemist. These are the smallest heritable 

 units that a plant or animal may possess. Any distinct 

 entity that can be traced from one generation to another, 

 such as the presence or absence of pubescence on the leaves 

 or stems, the height of the plant, whether dwarf or tall, 

 the color of the flower or fruits, and very many others are 

 now known as unit-characters. The more any group of 

 plants is studied, the more definite and distinct these 

 unit-characters become. The time may come when the 

 gardener, from long experience, shall become acquainted 



