“I wasn’t going to be bullied by a beast,” said Benham.

“Suppose it had been an elephant?” Prothero cried. . . .  “A mad elephant? . . .  A pack of wolves?”

Benham was too honest not to see that he was entangled.  “Well, suppose in your case it had been a wild cat? . . .  A fierce mastiff? . . .  A mastiff? . . .  A terrier? . . .  A lap dog?”

“Yes, but my case is that there are limits.”

Benham was impatient at the idea of limits.  With a faintly malicious pleasure Prothero lugged him back to that idea.

“We both admit there are limits,” Prothero concluded.  “But between the absolutely impossible and the altogether possible there’s the region of risk.  You think a man ought to take that risk—­” He reflected.  “I think—­no—­I think not.”

“If he feels afraid,” cried Benham, seeing his one point.  “If he feels afraid.  Then he ought to take it. . . .”

After a digestive interval, Prothero asked, “Why?  Why should he?”

The discussion of that momentous question, that Why? which Benham perhaps might never have dared ask himself, and which Prothero perhaps might never have attempted to answer if it had not been for the clash of their minds, was the chief topic of their conversation for many months.  From Why be brave? it spread readily enough to Why be honest?  Why be clean?—­all the great whys of life. . . .  Because one believes. . . .  But why believe it?  Left to himself Benham would have felt the mere asking of this question was a thing ignoble, not to be tolerated.  It was, as it were, treason to nobility.  But Prothero put it one afternoon in a way that permitted no high dismissal of their doubts.  “You can’t build your honour on fudge, Benham.  Like committing sacrilege—­in order to buy a cloth for the altar.”

By that Benham was slipped from the recognized code and launched upon speculations which became the magnificent research.

It was not only in complexion and stature and ways of thinking that Billy and Benham contrasted.  Benham inclined a little to eloquence, he liked very clean hands, he had a dread of ridiculous outlines.  Prothero lapsed readily into ostentatious slovenliness, when his hands were dirty he pitied them sooner than scrubbed them, he would have worn an overcoat with one tail torn off rather than have gone cold.  Moreover, Prothero had an earthy liking for animals, he could stroke and tickle strange cats until they wanted to leave father and mother and all earthly possessions and follow after him, and he mortgaged a term’s pocket money and bought and kept a small terrier in the school house against all law and tradition, under the baseless pretence that it was a stray animal of unknown origin.  Benham, on the other hand, was shy with small animals and faintly hostile to big ones.  Beasts he thought were just beasts.  And Prothero had a gift for caricature, while Benham’s aptitude was for music.