Dr. Blake, the physician, on the other hand, caught a certain languor in her movements, a physical tenuity which, in a patient, he would have considered diagnostic.  So transparent was her skin that when her profile dipped forward across a bar of sunshine the light shone through the bridge of her nose—­a little observation charming to Blake, the man, but a guide to Blake, the physician.  She had the look, Dr. Blake told himself, which old-fashioned country nurses of the herb-doctor school refer to as “called.”  He knew that, in about one case out of three, that look does in fact amount to a real “call”—­the outward expression of an obscure disease.

“Her heart?” queried Blake, the physician.  The transparent, porcelain quality of her skin would indicate that.  But he found, as he watched, no nervous twitching, no look as of an incipient sack under her eyes; nor did the transparent quality seem waxy.  There was, too, a certain pinkness in the porcelain which showed that her blood ran red and pure.

Then Mr. Blake and Dr. Blake re-fused into one psychology and decided that her appearance of delicacy was subtly psychological.  It haunted him with an irritating effect of familiarity—­as of a symptom which he ought to recognize.  In all ways was it intertwined with the expression of her mouth.  She had never smiled enough; therein lay all the trouble.  She presented a very pretty problem to his imagination.  Here she was, still so very young that little was written on her face, yet the little, something unusual, baffling.  The mouth, too tightly set, too drooping—­that expressed it all.  To educate such a one in the ways of innocent frivolity!

When the porter’s “last call for luncheon” brought that flutter of satisfaction by which a bored parlor-car welcomes even such a trivial diversion as food, Dr. Blake waited a fair interval for her toilet preparations, and followed toward the dining-car.  He smiled a little at himself as he realized that he was craftily scheming to find a seat, if not opposite her, at least within seeing distance.  On a long and lonely day-journey, he told himself, travelers are like invalids—­the smallest incident rolls up into a mountain of adventure.  Here he was, playing for sight of an interesting girl, as another traveler timed the train-speed by the mile-posts, or counted the telegraph poles along the way.

So he came out suddenly into the Pullman car ahead—­and almost stumbled over the nucleus of his meditations.  She was half-kneeling beside a seat, clasping in her arms the figure of a little, old woman.  He hesitated, stock still.  The blonde girl shifted her position as though to take better hold of her burden, and glanced backward with a look of appeal.  The doctor came forward on that; and his sight caught the face of the old woman.  Her eyes were closed, her head had dropped to one side and lay supine upon the girl’s shoulder.  It appeared to be a plain case of faint.