The doctor thought for a few minutes.  “Let’s see.  Suppose we assume that a certain human once happened to be in the neighborhood of a hive, just when it was attacked by a drove of ants.  Ants are great lovers of honey, you know.  Suppose the man stepped among the ants and was bitten.  Naturally he would trample them to death, and smash with his hands all that he couldn’t trample.  Now, what’s to prevent the bees from seeing how easily the man had dealt with the ants?  A man would be far more efficient, destroying ants, than a bee; just as a horse is more efficient, dragging a load, than a man.  And yet we know that the horse was domesticated, here on the earth, simply because the humans saw his possibilities; the horse could do a certain thing more efficiently than a human.

“You notice,” the doctor went on, with great care, “that everything I’ve assumed is natural enough:  the combination of an ant attack and the man’s approach, occurring at the same time.  Suppose we add a third factor:  that the bees, even while fighting the ants, also started to attack the man; but that he chanced to turn his attention to the ants first. So that the bees let him alone!

“We know what remarkable things bees are, when it comes to telling one another what they know.  Is there any reason why such an experience—­all natural enough—­shouldn’t demonstrate to them that they, by merely threatening a man, could compel him to kill ants for them?”

Billie was dubious for a moment; then agreed that the man, also, might notice that the bees failed to sting him as long as he continued to destroy their other enemies.  If so, it was quite conceivable that, bit by bit, the bees had found other and more positive ways of securing the aid of men through threatening to sting.  “Even to cultivating flowers for their benefit,” she conceded.  “It’s quite possible.”

Smith had been thinking of something else.  “I always understood that a bee’s stinging apparatus is good for only one attack.  Doesn’t it always remain behind after stinging?”

“Yes,” from the doctor, quietly.  “That is true.  The sting has tiny barbs on its tip, and these cause it to remain in the wound.  The sting is actually torn away from the bee when it flies away.  It never grows another.  That is why, in fact, the bee never stings except as a last resort, when it thinks it’s a question of self-defense.”

“Just what I thought!” chuckled Smith.  “A bee is helpless without its sting!  If so, how can you account for anything like a soldier bee?”

The doctor returned his gaze with perfect equanimity.  He looked at Van Emmon and Billie; they, too, seemed to think that the engineer had found a real flaw in Kinney’s reasoning.  The doctor dropped his eyes, and searched his mind thoroughly for the best words.  He removed his bracelets while he was thinking; the others did the same.  All four got to their feet and stretched, silently but thoroughly.  Not until they were ready to quit the study did the doctor make reply.