“I know I express myself incoherently, but I’ve tried to hammer out the idea.  It came to me as you were talking, so I was not primed and ready to deliver it.  You spoke yourself of the human frailty that prevented one from taking all the factors into consideration.  And you, in turn,—­or so it seems to me,—­leave out the biological factor, the very stuff out of which has been spun the fabric of all the arts, the warp and the woof of all human actions and achievements.”

To Ruth’s amazement, Martin was not immediately crushed, and that the professor replied in the way he did struck her as forbearance for Martin’s youth.  Professor Caldwell sat for a full minute, silent and fingering his watch chain.

“Do you know,” he said at last, “I’ve had that same criticism passed on me once before—­by a very great man, a scientist and evolutionist, Joseph Le Conte.  But he is dead, and I thought to remain undetected; and now you come along and expose me.  Seriously, though—­and this is confession—­I think there is something in your contention—­a great deal, in fact.  I am too classical, not enough up-to-date in the interpretative branches of science, and I can only plead the disadvantages of my education and a temperamental slothfulness that prevents me from doing the work.  I wonder if you’ll believe that I’ve never been inside a physics or chemistry laboratory?  It is true, nevertheless.  Le Conte was right, and so are you, Mr. Eden, at least to an extent—­how much I do not know.”

Ruth drew Martin away with her on a pretext; when she had got him aside, whispering:-

“You shouldn’t have monopolized Professor Caldwell that way.  There may be others who want to talk with him.”

“My mistake,” Martin admitted contritely.  “But I’d got him stirred up, and he was so interesting that I did not think.  Do you know, he is the brightest, the most intellectual, man I have ever talked with.  And I’ll tell you something else.  I once thought that everybody who went to universities, or who sat in the high places in society, was just as brilliant and intelligent as he.”

“He’s an exception,” she answered.

“I should say so.  Whom do you want me to talk to now?—­Oh, say, bring me up against that cashier-fellow.”

Martin talked for fifteen minutes with him, nor could Ruth have wished better behavior on her lover’s part.  Not once did his eyes flash nor his cheeks flush, while the calmness and poise with which he talked surprised her.  But in Martin’s estimation the whole tribe of bank cashiers fell a few hundred per cent, and for the rest of the evening he labored under the impression that bank cashiers and talkers of platitudes were synonymous phrases.  The army officer he found good-natured and simple, a healthy, wholesome young fellow, content to occupy the place in life into which birth and luck had flung him.  On learning that he had completed two years in the university, Martin was puzzled to know where he had stored it away.  Nevertheless Martin liked him better than the platitudinous bank cashier.