ood with clenched hands,
contemplating the intolerable and the monstrous.

Murgatroyd picked up the blaster. He trotted over to Calhoun. He
plucked at the man's trouser-leg again. He held the blaster in the
only way his tiny paw could manage it. A dark, sharp-nailed finger
rested on the trigger.

"_Chee-chee!_" said Murgatroyd.

He offered the blaster. Calhoun jumped when he saw it in Murgatroyd's
paw. The blaster jerked, and Murgatroyd's paw tightened to hold it. He
pulled the trigger. A blaster-bolt crashed out of the barrel. It was a
miniature bolt of ball-lightning. It went into the floor, vaporizing
the surface and carbonizing the multi-ply wood layer beneath it. The
Med Ship suddenly reeked of wood smoke and surfacer. Murgatroyd fled
in panic to his cubbyhole and cowered in its farthest corner.

But there was a singular silence in the Med Ship. Calhoun's expression
was startled; amazed. He was speechless for long seconds. Then he said
blankly:

"Damnation! How much of a fool can a man make of himself when he works
at it? Do you smell that?" He shot the question at the grid operator.
"Do you smell that? It's wood smoke! Did you know it?"

Murgatroyd listened fearfully, blinking.

"Wood smoke!" said Calhoun between his teeth. "And I didn't see it!
Men have had fires for two million years and electricity for half a
thousand. For two million years there was no man or woman or child who
went a full day without breathing in some wood smoke! And I didn't
realize that it was so normal a part of human environment that it was
a necessary one!"

There was a crash. Calhoun had smashed a chair. It was an oddity
because it was make of wood. Calhoun had owned it because it was odd.
Now he smashed it to splinters and piled them up and flung
blaster-bolt after blaster-bolt into the heap. The air inside the Med
Ship grew pungent; stinging; strangling. Murgatroyd sneezed. Calhoun
coughed. The grid operator seemed about to choke. But in the white fog
Calhoun cried exultantly:

"Aromatic olefines! Acetone! Acetic acid radicals and methyl
submolecular groups! And smoke has unsaturated hydrocarbon gases. This
is the stuff our ancestors have breathed in tiny quantities for a
hundred thousand generations! Of course it was essential to them! And
to us! It was a part of their environment, so they had to have a use
for it! And it controlled the population of certain molecules...."

The air system gradually cleared away the smoke