gray matter

Being short on gray matter as well as on stature, he wasn't getting it at all.

Of what use are the ganglia (gray matter) in the spinal cord?

The brain has not yet revealed its mysterious mechanism of gray matter.

And then, of course, there is the superior quality of our gray matter.

He tickled men's gray matter and kneaded it in his microscopic claws.

I can't trust my gray matter—I should make a dreadful fiasco.

You think, you will, you act according as that gray matter works.

Observe the soft, almost watery condition of that gray matter.

The organ is asthmatic and the wheezing gets on my gray matter.

"By using the gray matter at the back of my head," was the reply.