“Hm.” For a moment, he got a faraway look in his eyes, as though he were listening to something. “Do you know the term synaptic plasticity?”
“No, sir. I know what a synapse is.”
“The gap between one nerve cell and the next, yes. Synaptic plasticity is the tendency of the connection across the synapses to change in strength, either with use or with disuse. Among other things, it means the ability to change the quantity of neurotransmitters released into a synapse, and how well the next neuron in the chain responds to them. It’s an important factor in learning.”
“Okay …”
“Aspirin can affect synaptic plasticity. One of aspirin’s metabolic by-products, salicylate, acts on the NMDA receptors in cells, and that affects the flow of calcium ions across a neural synapse.”
At this point, Dr. Francis was way over my head. I had absolutely no idea what an NMDA receptor might be.
He must have sensed my confusion. “Don’t worry about it. My guess is Howell had a resident population of nanobots in his brain, programmed to give him an orgasm anytime he wanted, okay?”
I nodded.
“Dopamine is a neurotransmitter. One of the characteristics of neurotransmitters is you get a weakening effect each time you fire them.” He waved his hand in a descending series of peaks to illustrate. “You get this much of a jolt, then a little less, and a little less, like this. In an addiction, you need to boost the dosage of your drug of choice to get the same bang for your buck, right?”
“Yes, sir.” This was more familiar territory.
“Well, the same thing happens with dopamine. He might even have been going into withdrawal. Dopamine affects the same parts of the limbic system that heroin and cocaine hits.”
“Yeah. Headache. Runny nose. General aches and pains.”
“Symptoms like the flu,” Francis said. “Exactly. So he came to you to get you to prescribe a shot of nano, with the idea that more is better. He could reprogram what you gave him … or it looks like the nanobots he already had were set to reprogram anything new. You gave him aspirin instead. Maybe he took them back to the berthing compartment and downed them all, just hoping something would happen. The full chem workup we pulled on him this afternoon showed elevated salicylate levels.
“He might have boosted the programming on his nanobots, too. Upped the power, and maybe set them to deliberately give him an hour of multiple orgasms. We’ll know that if we find his N-prog in his locker. One way or another, though, the aspirin increased the efficiency of neurotransmitter uptake—specifically of dopamine. It also might have increased the triggering receptivity of his muscles. Aspirin is a decent muscle relaxant.”
The realization of what he was saying had just hit me, bam. “You’re saying I … I poisoned Howell, sir. I gave him that aspirin, and that’s what triggered the convulsions.”
“Not at all. I’m saying that when you’re working with these people, you need to be suspicious. Paranoid, even. What are they trying to put over on you?” He scowled. “It’s ridiculous. Most of them have fuck buddies in the squad bay, for God’s sake. Virtual reality feeds from the ship’s library let them have sex in their heads with all the hottest erotic stars on the Net. And still they screw with illegal nano programmers, trying to get a bigger kick, or they o-loop them to get a whole lot of them in a row.
“What happened wasn’t your fault. You didn’t know he was doing an onan, or that he was o-looping. But, damn it, be suspicious! If they’re showing fuzzy symptoms, or symptoms that don’t really make sense, do a scan and check for resident nano! If Howell had access to the stuff, it’s a sure bet that a dozen others on the Clymer are using, too. I’m going to need to take this to the skipper.”
“Yes, sir. Uh …”
“What?”
“What about me, sir? Am I on report?”
“Why would you be on report?”
“I screwed up. I missed the nano, I didn’t think of addiction when I saw him at sick call this morning, and I gave him enough aspirin to trigger those convulsions.”
Francis sighed. He raised his hand and began ticking points off on his fingers. “One, you didn’t ‘screw up.’ You could have been a little more persistent, a little more observant. But his symptoms looked like a clear call. The flu.
“Two. You’re not a doctor, nor do you have training in neurophysiology. At sick call, you screen the patients so that I don’t have to see all of them, and sort out the malingerers from the ones who are really sick. You’re trained to handle routine stuff. Colds and STDs and stubbed toes. Nanogenic dopamine addictive response is not routine.
“Three. One of the most complicated and difficult aspects of medicine is understanding how drugs or nano programs can interact or interfere with one another. It’s amazing how complicated things can get, with different drugs either reinforcing one another, or cancelling each other out—and with illegal nano, all bets are off!
“Four. Aspirin has been around since the late nineteenth century, unless you count shamans prescribing willow bark for pain, which is where the stuff came from. We’ve understood in general how it works since the late twentieth. But, believe me, even something that’s been around as long as aspirin can still surprise you. People have unusual sensitivities, or allergies, or they’re on drugs or nano treatments, or they’re shooting themselves full of crap that could kill them.
“And no one can keep up with all of the possibilities. That’s why we have expert systems, AIs with medical databases that let them guide us through the jungle of drug interactions. When in doubt, use them.”
I sagged a bit inside. “I do, when there’s a question,” I said. “But I didn’t have a question this time. I really thought Howell had a cold.”
“It happens to all of us, Carlyle. We make mistakes, we’re not perfect. Things could have turned out a lot worse for Private Howell, believe me. They didn’t. So … you made a mistake. Learn from it. Okay?”
“Yes, sir.”
“Good. Questions?”
“Just … is this going to affect my FMF training?”
“Hell, no. You’re a good Corpsman, and I want you on my team. So as far as I’m concerned, you’re in.”
“Thank you, sir.”
“You want liberty tonight?”
I thought about it. Right then, I really wanted to get off the ship. There was this bar in Supra-Cayambe I really liked: the Earthview.
“Yes, sir. If that’s okay …”
“Absolutely. Give me your hand.”
I extended my left hand, and he passed a wand over it. All military personnel have a programmable chip implanted in their left wrist and another in the back of their head. They serve as ID—what the military used to call dog tags—and can also carry orders and authorizations. My CDF in-head hardware—my Cerebral Data Feed implants—could also carry orders, of course, but the Navy takes a dim view of enlisted personnel writing or rewriting their own.
What Dr. Francis had just done was give me an authorization, signed by him, my department head, to leave the ship for twelve hours, what both the Navy and the Marine Corps refer to as liberty.
I was free for the evening, unless, of course, we had an emergency recall.
“Have you heard anything about when we’re shipping out again, sir?” I asked.
“Not a word. I wouldn’t worry about it. If they’re putting together an out-system expeditionary force,