'em
standin' here beside me, hand in hand, doc!"

The doctor, even by that dim light, had changed colour. He passed his
hand slowly across his forehead.

"You expect to see that?"

"I expect nothin'. I only hope!"

The bitterness of Byrne's heart came up in his throat.

"It will be an oddly suited match," he said, "if they marry. But they
will not marry."

"Ha!" cried Cumberland, and starting up in bed he braced himself on a
quaking elbow. "What's that?"

"Lie down!" ordered the doctor, and pressed the ranchman back against
the pillows.

"But what d'you mean?"

"It would be a long story--the scientific explanation."

"Doc, where Dan is concerned I got more patience than Job."

"In brief, then, I will prove to you that there is no mystery in this
Daniel Barry."

"If you can do that, doc, you're more of a man than I been guessing you
for. Start now!"

"In primitive times," said Doctor Randall Byrne, "man was nearly related
to what we now call the lower animals. In those days he could not
surround himself with an artificial protective environment. He depended
on the unassisted strength of his body. His muscular and sensuous
development, therefore, was far in advance of that of the modern man.
For modern man has used his mind at the expense of his body. The very
_quality_ of his muscles is altered; and the senses of sight and
hearing, for instance, are much blunted. For in the primitive days the
ear kept guard over man even when he slept in terror of a thousand
deadly enemies, each stronger than he; and the eye had to be keenly
attuned to probe the shadows of the forest for lurking foes.

"Now, sir, there is in biology the thing known, as the sport. You will
have heard that all living organisms undergo gradual processes of
change. Season by season and year by year, environment affects the
individual; yet these gradual changes are extremely slow. Between steps
of noticeable change there elapse periods many times longer than the
life of historic man. All speed in changes such as these comes in what
we call 'sports'. That is, a particular plant, for instance, gradually
tends to have fewer leaves and a thicker bark, but the change is slight
from age to age until suddenly a single instance occurs of plant which
realises suddenly in a single step the 'ideal' towards which the species
has been striving. In a word, it has very, very few leaves, and an
extraordinarily thick bark.

"For a particular instance, one