Jack faced around.  The doctor, meeting a calm eye that was quizzically challenging, paused abruptly, feeling that in some way he had been caught at a professional disadvantage in his outburst of emotion.

“Don’t you like Little Rivers?” asked Jack.

“I should be bored to death!” the doctor admitted, honestly.

“Well, you see this air never healed a lesion for you!  You never uttered a prayer to it for strength with every breath!  And, doctor,” Jack hesitated, while his lips were half open, showing his even teeth slightly apart in the manner of a break in a story to the children where he expected them to be very attentive to what was coming, “you can take a piece of tissue and analyze it, yes, a piece of brain tissue and find all the blood-vessels, but not what a man was thinking, can you?  Until you can take a precipitate of his thoughts—­the very thoughts he is unconscious of himself—­and put them under a microscope, why, there must be a lot of guesswork about the source of all unconventional human actions.”

Jack laughed over his invasion of psychology; and when he laughed in a certain way the impulse to join him was strong, as Mary first found on the pass.  So the doctor laughed, partly in relief, perhaps, that this uncertain element which he was finding in Jack had not yet proved explosive.

“That would make a capital excuse for a student flunking in examinations!” he said.

“It might be a worthy one—­not that I say it ought to pass him.”

“Now, Jack,” the doctor began afresh, the reassuring force of his personality again in play.

He took a step and raised his hands as if he would put them on Jack’s shoulders.  One could imagine him driving hypochondria out of many a patient’s mind by thus making his own vigorous optimism flow down from his fingertips, while he looked into the patient’s eye.  But his hands remained in the air, though Jack had been only smiling at him.  This was not the way to handle this patient, something told his trained, sensitive instinct in time, and he let his hands fall in semblance of a gesture of protest, gave a shrug and came directly to the point very genuinely.

“Well, Jack—­your father!”

“Yes.”  And Jack’s face was still and blank, while shadows played over it in a war among themselves.  “He did not even tell me you were coming,” he added.

“Perhaps he feared that it would give you time to develop a cough or you would start overland to Chihuahua so I should miss you.  Jack, he needs you!  All that fortune waits for you!”

“Now that I am strong, yes!  He did not come out to see me even during the first year when I had not the health to go to him, nor did he think to come with you.”

“He—­he is a very busy man!” explained the doctor, in ready championship.  And yet he looked away from Jack, and when he looked back it was with an appeal to conscience rather than to filial affection.  “Is it right to remain, however much you like this desert life?  Have you any excuse?”