"They—they aren't dangerous to man?"

The sideways rocking motion.

"They're a danger to some men—Baxter's men!"

A nod, but with a kind of hesitation about it.

"But also to the boys?" I marvelled.

The yes-no motion.

"Under certain conditions, they're a danger to the boys!"

Yes.

"These conditions; do they have anything to do with Baxter?"

Yes.