They get fussed and nervous, and weaken before he's said a single word.

But it was certain now that the mystery was getting to Safety, because
otherwise he'd have laughed his head off at the mention of a hundred
dollars for these mules. Three months before he'd heard me himself offer
'em for forty a head. You see, when I bought bands of mules from time to
time I'd made the sellers throw in the little ones to go free with the
trade. I now had twenty-five or so, but it had begun to get to me that
mebbe those sellers hadn't been so easy as I thought at the time. They
was knotty-headed little runts that I'd never bothered to handle.

Last spring I had the boys chink up the cracks in the corral and put each
one of the cunning little mites into the chute and roach it so as to put
a bow in its neck; then I put the bunch on good green feed where they
would fatten and shed off; but it was wasted effort. They looked so much
like field mice I was afraid that cats would make a mistake. After they
got fat the biggest one looked as if he'd weigh close up to seven hundred
and fifty. It was when they had begun to buy mules too; that is to say,
mules! But no such luck as a new West Pointer coming to inspect these;
nothing but wise old cavalry captains that when they put an eye on the
bunch would grin friendly at me and hesitate only long enough to put some
water in the radiator. I bet there never was a bunch of three-year-old
mules that stood so much condemning.

After offering 'em for forty a head one time to a party and having him
answer very simply by asking how the road was on beyond and which turn
did he take, I quit bothering. After that when buyers come along I told
the truth and said I didn't have any mules. I had to keep my real ones,
and it wasn't worth while showing those submules. And this was the bunch
Sandy had told S.F. Timmins he could take away for a hundred a head--or