“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 species of orange tended to have few and fewer seeds.  But finally came an orange tree whose fruit had no seeds at all.  That was the origin of the navel orange.  And that was a typical ‘sport’.

“Now, there is the reverse of the sport.  Instead of jumping long distance ahead, an individual may lapse back towards the primitive.  That individual is called an atavism.  For instance, in this mountain-desert there has, for several generations, been a pressure of environment calling for a species of man which will be able to live with comparative comfort in a waste region—­a man, in a word, equipped with such powerful organisms that he will be as much at home in the heart of the desert as an ordinary man would be in a drawing-room.  You gather the drift of my argument.

“I have observed this man Barry carefully.  I am thoroughly convinced that he is such an atavism.

“Among other men he seems strange.  He is different and therefore he seems mysterious.  As a matter of fact, he is quite a common freak.  I could name you others like him in differing from common men, though not differing from them in exactly the same manner.