"_Ergo,_ you believe that what is behind affects what is in front?"

_"Nego!"_ the student cried with still more ardor, feeling another
jerk at his coat.

Juanito, or rather Placido, who was prompting him, was unconsciously
adopting Chinese tactics: not to admit the most inoffensive foreigner
in order not to be invaded.

"Then where are we?" asked the professor, somewhat disconcerted,
and looking uneasily at the refractory student. "Does the substance
behind affect, or does it not affect, the surface?"

To this precise and categorical question, a kind of ultimatum, Juanito
did not know what to reply and his coat offered no suggestions. In vain
he made signs to Placido, but Placido himself was in doubt. Juanito
then took advantage of a moment in which the professor was staring
at a student who was cautiously and secretly taking off the shoes
that hurt his feet, to step heavily on Placido's toes and whisper,
"Tell me, hurry up, tell me!"

"I distinguish--Get out! What an ass you are!" yelled Placido
unreservedly, as he stared with angry eyes and rubbed his hand over
his patent-leather shoe.

The professor heard the cry, stared at the pair, and guessed what
had happened.

"Listen, you meddler," he addressed Placido, "I wasn't questioning
you, but since you think you can save others, let's see if you can