"We know that, too," agreed Drake. "We have no choice."
"Why?" cried Rose. "Harg Tholan gave you the solution. He made no suggestions or threats of war between worlds. He suggested that we combine with the other intelligences and help to wipe out the parasite. And we can! If we, in common with all the others, put every scrap of effort into it - "
"You mean we can trust him? Does he speak for his government or for the other races?"
"Can we dare to refuse the risk?"
Drake said, "You don't understand." He reached toward her and took one of her cold, unresisting hands between both of his. He went on, "I may seem silly trying to teach you anything about your specialty, but I want you to hear me out. Harg Tholan was right. Man and his prehistoric ancestors have been living with this parasitic intelligence for uncounted ages; certainly for a much longer period than we have been truly Homo sapiens. In that interval, we have not only become adapted to it, we have become dependent upon it. It is no longer a case of parasitism. It is a case of mutual cooperation. You biologists have a name for it."
She tore her hand away. "What are you talking about? Symbiosis?"
"Exactly. We have a disease of our own, remember. It is a reverse disease; one of unrestrained growth. We've mentioned it already as a contrast to the Inhibition Death. Well, what is the cause of cancer? How long have biologists, physiologists, biochemists and all the others been working on it? How much success have they had with it? Why? Can't you answer that for yourself now?"
She said, slowly, "No, I can't. What are you talking about?"
"It's all very well to say that if we could remove the parasite, we would have eternal growth and life if we wanted it; or at least until we got tired of being too big or of living too long, and did away with ourselves neatly. But how many millions of years has it been since the human body has had occasion to grow in such an unrestrained fashion? Can it do so any longer? Is the chemistry of the body adjusted to that? Has it got the proper whatchamacallits?"
"Enzymes," Rose supplied in a whisper.
"Yes, enzymes. It's impossible for us. If for any reason the parasitic intelligence, as Harg Tholan calls it, does leave the human body, or if its relationship to the human mind is in any way impaired, growth does take place, but not in any orderly fashion. We call the growth cancer. And there you have it. There's no way of getting rid of the parasite. We're together for all eternity. To get rid of their inhibition Death, extraterrestrials must first wipe out all vertebrate life on Earth. There is no other solution for them, and so we must keep knowledge of it from them. Do you understand?"
Her mouth was dry and it was difficult to talk. "I understand, Drake." She noticed that his forehead was damp and that there was a line of perspiration down each cheek. "And now you'll have to get it out of the apartment."
"It's late at night and I'll be able to get the body out of the building. From there on - " He turned to her. "I don't know when I'll be back."
"I understand, Drake," she said again.
Harg Tholan was heavy. Drake had to drag him through the apartment. Rose turned away, retching. She hid her eyes until she heard the front door close. She whispered to herself, "I understand, Drake."
It was 3 a.m. Nearly an hour had passed since she had heard the front door click gently into place behind Drake and his burden. She didn't know where he was going, what he intended doing - She sat there numbly. There was no desire to sleep; no desire to move. She kept her mind traveling in tight circles, away from the thing she knew and which she wanted not to know.
Parasitic minds! Was it only a coincidence or was it some queer racial memory, some tenuous long-sustained wisp of tradition or insight, stretching back through incredible millennia, that kept current the odd myth of human beginnings? She thought to herself, there were two intelligences on Earth to begin with. There were humans in the Garden of Eden and also the serpent, which "was more subtil than any beast of the field." The serpent infected man and, as a result, it lost its limbs. Its physical attributes were no longer necessary. And because of the infection, man was driven out of the Garden of eternal life. Death entered the world.
Yet, despite her efforts, the circle of her thoughts expanded and returned to Drake. She shoved and it returned; she counted to herself, she recited the names of the objects in her field of vision, she cried, "No, no, no," and it returned. It kept returning.
Drake had lied to her. It had been a plausible story. It would have held good under most circumstances; but Drake was not a biologist. Cancer could not be, as Drake had said, a disease that was an expression of a lost ability for normal growth. Cancer attacked children while they were still growing; it could even attack embryonic tissue. It attacked fish, which, like extraterrestrials, never stopped growing while they lived, and died only by disease or accident. It attacked plants which had no minds and could not be parasitized. Cancer had nothing to do with the presence or absence of normal growth; it was the general disease of life, to which no tissue of no multicellular organism was completely immune.
He should not have bothered lying. He should not have allowed some obscure sentimental weakness to persuade him to avoid the necessity of killing her in that manner. She would tell them at the Institute. The parasite could be beaten. Its absence would not cause cancer. But who would believe her?
She put her hands over her eyes. The young men who disappeared were usually in the first year of their marriage. Whatever the process of reproduction of the parasite intelligences, it must involve close association with another parasite - the type of close and continuous association that might only be possible if their respective hosts were in equally close relationship. As in the case of newly married couples.