Truggles stared at him, unable to answer. This interview was beginning to take on a nightmarish aspect. "What do you consider to be the principal difference between mice and men, Mr. Truggles?" pursued Allison. "Really, Dr. Allison, I don't see--I don't know what point you're trying to make, but a mouse is an animal and a man is--well, a man." "Nothing else?" "Well, a man is bigger than a mouse." He began to feel familiar ground under his feet. "A man is bigger more ways than physically. He is bigger spiritually, emotionally. He thinks. He has a--" "Ben Sands told me about his talk with you. So you don't believe in evolution? You don't believe the ancestors of men and monkeys came from a common stock?" "I do not, sir. It is inconceivable...." "How would mice strike you, then? Would you rather believe that men descended from mice than monkeys?" Again the bewildered Truggles found himself physically incapable of answering. "I have done a great deal of research, with the kind assistance of Blan Forsythe," said Allison precisely. "Blan is my friend. He has been my associate, even my experimental animal. I am preparing a paper on what I consider a revolutionary contribution to the theory of evolution--that men are related directly to the genus _rodentia_, and only more distantly so to the primates. "Blan Forsythe is the real originator of this theory, as a result of his very personal interest in sudden evolutionary changes through doubling of chromosomes. It is reasonable to suppose that the ancestor of man himself, with all of his survival advantages, arose through such a process. Man has 48 chromosomes. Now, Mr. Truggles, what sort of animal would you guess has half that number--24 chromosomes?" "Mice?" hazarded Truggles thinly. "Precisely. Mice. The common house mouse. There is also a variety of squirrel that carries 24 chromosomes. The _peromyscus_ and _apodemus_ families of mice--and some other animals, including the rhesus monkey--have 48--cousins whose chromosome doubling eons ago started them up different paths from ours. Mr. Truggles, the ancestor of man was a rodent whose doubled chromosomes gave him new attributes that worked to his evolutionary advantage." "Is that what is called a mutation?" asked Truggles, interested in spite of himself. "Mutation? A mutation is a change in one gene. Men mutate every day. How many millions upon millions of years do you think it would take simple mutations to build a man from a rodent--or a lemur, either, for that matter?" "Well, really, Dr. Allison, I believe you misunderstand what I asked you. Your theory is fine, I'm sure, among scientists, but I'm interested in information about Blan Forsythe." "That's what I've given you. Blan Forsythe is a tetraploid man. His cells carry 96 chromosomes instead of the normal 48. Every cell of his body is doubled." "Is that why his skin is liver-colored?" asked Truggles, remembering what Sands had said. Allison smiled.