variation is a general phenomenon among the best known species of 
animals and plants. Unfortunately very few naturalists pay attention 
to individual variations.”—(Fortnightly Review, vol. xl., p. 307.) 
If we represent the differences which occur among the 
inevitable variations associated with sexual reproduction 
from the point of view of direction, we shall find a similar 
difference of opinion. 
They are represented as divergent, as varying in all 
directions. 
“ Natural Selection, or survival of the fittest, among divergent 
varieties of offspring, is the distinctive Darwinian factor.”—(Le Conte. 
Evolution and its Relation to Religious Thought, ft. 74.) 
“ The theory requires—variations of all parts in all directions.— 
(Mivart. The Genesis of Species, ft. 60.) 
“ All that this theory has to do, is to take the principle of promis 
cuous variation in all directions, as a datum supplied by observation.” 
—(Romanes. Nature, vol. xxxiv., ft. j6o, note.) 
“The Darwinist can point to the results of‘artificial selection’ 
unquestionably to demonstrate that, in our domesticated plants, and 
animals, variation is so far omniferous as to lend itself to all the 
morphological changes in divergent lines which have been produced 
by the continuous, or cumulative, selection of the horticulturist and 
the breeder.”—(Romanes. Contemporary Review, vol. liii., p. 850.) 
In the second place it is asserted that the variations 
cluster around a central line, from which a few variants 
diverge on either side. 
Professor George H. Darwin says :— 
“ One may assume, with some confidence, that under normal 
conditions, the variation of any organ in the same species—may 
be symmetrically grouped about a centre of greatest density.”— 
(Nature, vol. viii., p. jog.) 
“ If one were to draw a vertical line on a wall, and were to measure 
the heights of several thousand men of the same race against this 
line, recording the height of each by driving in a pin, the pins 
would be densely clustered about a certain height, and the density 
of their distribution would diminish above and below. Quetelet 
experimentally verified that the density of the pins at any distance