“Binding to D-alanine takes almost no time here on Grass because there’s so much D-alanine around. Someplace like Terra, where there are maybe only a few accidental molecules, it could take a long, long time. That’s why the plague was so slow to start elsewhere. It’s also why there isn’t any plague here on Grass. As soon as we started breathing on Grass, all our cells got supplied with D and L both.
“So, here on Grass, the virus inverts L, which we need in order to live, to D, which our bodies can’t use. However, since both D and L are plentiful, it turns both forms around simultaneously, and each of our cells finds enough L-alanine to go on living. On other planets there was little or no D-alanine to start with. When L was reversed, only D was left, and the cells couldn’t use it. When human cells died, the viruses escaped into neighboring cells in their immediately infective stage, and the process was repeated. People got sores that spread. Bandages, wash water, anything that touched the body served as a source of infection, and the dead cells provided the co-factor for newly infected cells.”
“But not here,” Rigo said stiffly.
“Not here. On Grass, both D-alanine and L-alanine are plentiful; our cells survive. The virus’s life cycle is interrupted, the cells die naturally. People come here and get infected and go away, never knowing it….”
“And it was spread by bats?” Father Sandoval asked.
“Lees says the bats don’t use alanine. It’s only one of a number of amino acids, and the bats just don’t use it. However, the blood of other animals has alanine in it. The bat doesn’t need it, so the viruses and the co-factors exist in the bat’s blood bladder. When bats die and dry, their insides are powdery with virus-rich material, as packed with viruses and with co-factors as a puffball is with spores. Dead blood-sucking bats are about as good a carrier as you could get.”
“You haven’t said what the cure is,” Father Sandoval said, finding on Rigo’s face an expression which reinforced his own mood, one of frustrated anger. One could not be angry that a cure had been found; one was, however, annoyed at the way it had been found.
“The cure?” She looked up, puzzled. “Well, of course, Father. I thought that was self-evident. All that’s needed is to spread massive quantities of D-alanine around. Small doses are no good. If somebody gets small doses of D, it will bind to the enzyme and they’ll die. But
grass •413
if they get massive amounts, more than is needed to bind, then there will be equal mixtures of L to D and D to L conversion And, of course, Semling found that it was extremely easy to make. They just used the virus to manufacture it out of L-alanine.”
Father Sandoval shook his head. “It sounds so simple the way you describe it. But the Arbai couldn’t cure it, as wise as they were?” He would not believe in their wisdom, no matter what Father James had said. Furthermore, he felt the church would disbelieve in their wisdom as well. Doctrine, as he knew it, had no room for other children of God.
“Perhaps they died faster than we did. My informant doesn’t know.
“Your informant?” Rigo said, his voice ugly. “A foxen! Horses weren’t enough for you, Marjorie?”
She frowned at him warningly, repressing her sudden anger. “Don’t, Rigo. If you are ambassador to Grass, you are ambassador to them, as well. They aren’t animals.”
“That is not for you to decide,” the priest said, echoing her anger with a sullen fury of his own. “That is a question for the church, Marjorie. Not for you. They may be intelligent and still be animals. Your relationship with them may be a serious error. I caution you!”
“You what?” she asked, incredulous. “You what?”
“I caution you. On pain of excommunication, Marjorie. Do not continue in this mindless adulation of these creatures.”
She looked at the priest, betraying nothing. His face was red, then white. His hand, resting upon the table, was clenched. Rigo looked much the same. They had been discussing her again. Talking over how she was to be controlled, no doubt. Her mind scuttered in its usual pattern of evasion, of compromise, then stopped as though it had run into a wall.