the day after, paying twenty francs each time, but the old man had the
addresses of all his clients and shrewdly knew their needs, and soon
the right two met and eagerly exchanged their commodities.
"Commodities" was the old man's terrible word, said with a gruesome
smack of his heavy lips, for he took a pride in his business and evils
to him were goods.

I learned from him in ten minutes very much of human nature, more than
I have ever learned from any other man; I learned from him that a
man's own evil is to him the worst thing there is or ever could be,
and that an evil so unbalances all men's minds that they always seek
for extremes in that small grim shop. A woman that had no children had
exchanged with an impoverished half-maddened creature with twelve. On
one occasion a man had exchanged wisdom for folly.

"Why on earth did he do that?" I said.

"None of my business," the old man answered in his heavy indolent way.
He merely took his twenty francs from each and ratified the agreement
in the little room at the back opening out of the shop where his
clients do business. Apparently the man that had parted with wisdom
had left the shop upon the tips of his toes with a happy though
foolish expression all over his face, but the other went thoughtfully
away wearing a troubled and very puzzled look. Almost always it seemed
they did business in opposite evils.

But the thing that puzzled me most in all my talks with that unwieldy
man, the thing that puzzles me still, is that none that had once done
business in that shop ever returned again; a man might come day after
day for many weeks, but once do business and he never returned; so