III. THE MATERIAL VEHICLES OF THE 
HEREDITARY CHARACTERS. 
9. DARWIN'S PANGENESIS. 
The real meaning of the title of DARWIN'S book, 
On the Origin of Species by Means of Natural Selection, 
has often been largely misapprehended. In DARWIN'S 
mind the emphasis lay on the word "natural." He pleaded 
a natural origin of species against the accepted super- 
natural one. The whole object of his work was to show 
that the genetic relationships of animals and plants may 
be explained without invoking supernatural causes, and 
that their explanation by natural means is far more satis- 
factory and simple. For this conviction he succeeded 
in obtaining general credence, and thus laid a broad foun- 
dation for all future investigation in this sphere. 
The modern tendency, however, is to shift the em- 
phasis on the word selection and on the analogy between 
selection in nature and the artificial production of races 
in agriculture. In doing so it is often overlooked that 
half a century ago the science of the various forms of 
variability, and consequently of selection, was still in its 
infancy, and that we must not apply our present knowl- 
edge to the state of opinions which prevailed then. Xo 
distinction was drawn at that time, for instance, between 
mutability and variability; and it was DARWIN who first 
