The creatures that remained would propagate themselves by using other humans unless they were stopped.

Moreover, for many experiments it is not ethical or practical to use humans.

You/I agreed, long ago, to use humans against the quasi-mechanicals.

The reason they use humans here is because they are far from their Centre and very weak.

They don't use humans as hosts, There has to be some kind of mistake.

"Or plans to expand to using humans to do Hex's dirty work?"

I explained to him that we can't use humans,' he said. '

Other species of old Earth used and made tools, but only humans need them to survive.

I have to struggle to retain even the word they use to describe themselves: humans.

Scientists might be reduced to using only humans as guinea pigs.