18 
CHOICE BRITISH FERNS. 
rendered a dark and impenetrable mystery, until some benefi- 
cent fairy should step in and restore the long noses, short 
noses, snub, Semitic and Roman noses, thick lips, thin lips, 
big mouths like caves, and little ones like rosebuds, &c., 
which now render recognition easy, enabling us skilfully 
to evade a bore on the one hand and to buttonhole our un- 
suspecting friends on the other, or to meet our new loves 
and avoid our old ones, with a fair certainty of not reversing 
the process by mistake. 
Amongst our fellow-countrymen our powers of recognition 
in this respect are sharp enough ; but if we went, say to China, 
we should find that the general characteristics of high cheek- 
bones, slanting eyes, sallow complexions, short noses, and pig- 
tails, would necessitate a certain apprenticeship before we 
could easily detect the celestial John Smith from the celestial 
Tom Robinson, though the difi'erence between the two, to 
celestial eyes, is probably striking enough. 
To descend a bit in the scale of creation. To the ordinary 
observer it would be impossible to detect, much less define, 
the difference between one sheep and another in a flock of 
the same breed, yet the breeder will have no difficulty in 
finding better or worse points among them; while it is 
notorious that many shepherds can recognise, unfailingly, every 
sheep in their care. These external differences between the 
individuals are further supplemented by, and are partly the 
result of, differences in temper and constitution, which repre- 
sent what may be termed moral variation, as distinct from 
physical. These differences, subtle or manifest, characterise 
every individual thing in creation; so that it may safely be 
affirmed that there are no two living beings, from the monad 
to the man, which, however alike apparently, would not, if 
brought together and compared, be found to differ, not only 
in one, but in many respects — i.e., would betray variation. 
The tendency of Nature is, by the free intercourse among 
the various individuals of a species, to check the growth of 
any type of variation in special directions, and so to main- 
tain a fair level of uniformity; if, however, a change of the 
conditions of existence be brought about, then any variations 
