much about mutation. Some claimed a
little radioactivity would cause it, some said a whole lot, and some
said it wouldn't hurt a bit."

"Whaa mootyaaonn?" asked the calf which was not yet assured of the
extinction of Atomic Bomb.

"Well, you-all are all mutations. I've told you how life starts from one
cell. This cell has thread-like things in it called chromosomes, and the
chromosomes are made up of things called genes. Mutations, sort of
unexpected changes, can take place in either the chromosomes or the
genes. You see, when this one cell starts dividing, every gene makes a
copy of itself; but, sometimes, the copy is a little different from the
original. Lots of things, like x-rays and ultraviolet rays, heat,
chemicals, disease, can cause this. Radioactivity had caused mutation in
some experiment, so the scientists were anxious to see what happened
with these cattle.

"Genes determine the way an animal develops. Two mutant genes can start
reactions that end up as a man with one leg, or maybe as a bull with the
intelligence of an eight-year-old man. Lots of mutations are recessive.
They may be carried along for generations. But, when two like mutant
genes come together in reproduction, the animal is bound to be something
different, the way you eleven calves are.

"Now. The scientists watched the Atohmy cattle for fifteen or twenty
years, and nothin' much happened. They started sayin' radioactivity
wasn't dangerous, and a man could walk into a place right after Atomic
Bomb went off, and it wouldn't matter. They should be here to see the
mess in Japan today. All the time, though, I think the cattle were
changing. It may have been in little things like the length of hair, or
the shape of an eyeball, or the curve of a horn, so the scientists
couldn't tell without they made exact measurements all the time.

"Then, a bull-calf was born. He had shaggy black hair, and his horns
grew in a spiral like a ram's. Some scientists said, 'I told you so! It
speeded the mutation rate!'

"Others said, 'He's a natural mutation, or else, a throw-back to
prehistoric wild cattle. It happens in every breed. Atomic Bomb had
nothing to do with it.'

"They married the bull, and then they fixed to slaughter 'im to see what
his insides was like. The bull fooled 'em, though. He came down with
contagious pleuro-pneumonia, the first case in years, 'cause it was
supposed to have been wiped out in this country away back in the
Nineteenth Centu