"They were just plain Whiteface cattle. They weren't supposed to be there, but I reckon none of the scientists bothered to warn 'em. The dust started settlin' all over your ancestors. In about a week, there were sores and blisters on their backs. The red hair dropped off. When it grew back, it was gray. "The scientists got real excited when they heard about it, 'cause they wanted to see how horrible they could make Atomic Bomb. So, they shipped fifty-nine cattle up to Oak Ridge. That was a Government town, a hundred miles southwest of here, where they made some of the stuff to put in Atomic Bomb. The University of Tennessee was runnin' an experimental farm there. They had donkeys, and pigs, and chickens, and other animals that they exposed to radioactivity. Then they killed 'em and cut 'em up to see what had happened. I know it's gruesome, but that's how it was. "The awful fact is, the scientists slaughtered more than half that original Atohmy herd for experiments. Some of the rest, they--uh--married. Wanted to see if the calves had two heads, or something; if radioactivity had speeded up the mutation rate. "Back then, they didn't understand 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.