He implants it in a young woman he has been having an affair with, a woman who lives on Starlight Island. She sleeps with some of the other men in the building and spreads the parasite. A stubby worm the size of a child’s foot, it lives in people’s guts and passes from mouth to mouth during a kiss. It transforms people into sexual monsters, attacking each other in apartments, laundry rooms, elevators. Rape, incest, and all sorts of other depravity erupt.
The physician for Starlight Island spends most of the movie trying to stop the parasite from spreading. At one point he has to shoot a man attacking his nurse (and girlfriend), and they escape to the basement. As they cower there, the nurse tells him that she had a dream the night before in which she was making love to an old man. The old man told her that everything is erotic, everything is sexual, “that disease is love of two alien kinds of creatures for each other.” Whereupon she tries to kiss the doctor, with a parasite crouched in her mouth ready to spring. He knocks her out cold. He tries to escape the building, but hordes of infected hosts ring him in and herd him into the building’s swimming pool. His nurse is there, and she finally gives him a fatal kiss. Later that night, all the residents drive out of the garage and leave the island, to spread the parasite and its mayhem throughout the city.
As I watched these movies, I was struck by how easy it was to translate biological reality into movie horror. The creature in Alien comes as no surprise to the entomologist who studies parasitic wasps. Heinlein may not have known that parasites can take over the behavior of their hosts, but he nailed the essence of their control. It may seem ridiculous that the parasites in Shivers can spread themselves by making people have sex, but it’s no more ridiculous than what actual parasites do. The fungus that I discussed earlier, which infects flies and forces them to climb up grass in the evening, actually uses a second trick to spread itself as well. It makes the corpse of its host a sexual magnet. Something about the fly—something brought about by the fungus itself—makes it irresistible to uninfected male flies. They will try to mate with it, preferring it to living flies. As they grope the corpse they become covered with spores themselves. When they die, they themselves become irresistible. When will someone make their movie?
Of course, these parasites are more than just parasites. In Shivers, Cronenberg uses them to expose the sexual tension buried under the blandness of modern life. In The Faculty, parasites represent the stupefying conformity of high school, which only outsiders can fight. And in The Puppetmasters, written in the McCarthyite fifties, the parasites are Communism: they hide within ordinary-seeming people, they spread silently across the United States, and they have to be destroyed by any means necessary. At one point the narrator says, “I wonder why the titans [the narrator’s name for the aliens] had not attacked Russia first; Stalinism seemed tailormade for them. On second thought, I wondered if they had. On third thought, I wondered what difference it would make; the people behind the Curtain had had their minds enslaved and parasites riding them for three generations.”
But all these works do have something in common: they play on a universal, deep-seated fear of parasites. This horror is new, and for that reason it’s interesting. There was a time when parasites were treated with contempt, when they stood for the undesirable, weak elements of society that got in the way of its progress. Now the parasites have gone from weak to strong, and now fear has replaced contempt. Psychiatrists actually recognize a condition they call delusional parasitosis—a terror of being attacked by parasites. The old parasite metaphors, the ones used by people like Hitler and Drummond, were remarkably precise in their biology. And, judging from movies like Alien and The Faculty, so is the new one. It is not just a fear of being killed; it’s a fear of being controlled from within by something other than our own minds, being used for something else’s ends. It’s a fear of becoming a flour beetle controlled by a tapeworm.
This precise horror of parasites has its roots in how we now see our relationship to the natural world. Before the nineteenth century, Western thought saw humans as distinct from the rest of life, created by God with a divine soul in the first week of Genesis. It became harder to keep that dividing line fixed as scientists compared our bodies with those of apes and found the differences to be pretty minor. And then Darwin explained why: humans and apes are related by common descent, as is all of life. The twentieth century has given his realization a fine-grained detail, moving from bones and organs down to cells and proteins. Our DNA is only a shade different from that of chimpanzees. And like a chimpanzee, or a turtle or a lamprey, we have brains that consist of crackling neurons and flowing neurotransmitters. These discoveries may give some comfort if you look at them one way: we belong on this planet as much as the oak and the coral reef, and we should learn to get along better with the rest of the family of life.
But look at them another way, and they bring horror. Copernicus took the Earth out of the center of the universe, and now we have to accept the fact that we live on a watery grain in an overwhelming void. Biologists like Darwin did a similar thing, taking humanity out of its privileged place in the living world—a biological Copernicanism. We still go through life pretending that we are exalted above other animals, but we know that we too are collections of cells that work together, kept harmonized not by an angel but by chemical signals. If an organism can control those signals—an organism like a parasite—then it can control us. Parasites look at us coldly—as food, or perhaps as a vehicle. When an alien bursts out of a movie actor’s chest, it bursts through our pretenses to be more than brilliant creatures. It is nature itself that is bursting through, and it terrifies us.
5
The Great Step Inward
Whence, thinkest thou, kings and parasites arose?
There are billion-year-old secrets at the University of Pennsylvania, but they are well hidden from view in the laboratory of a biologist named David Roos. The sunlight of a soft Philadelphia sky flows through high windows into the lab, where Roos’s graduate students are laying flasks of cherry-colored liquids under microscopes, kneading data on computers, clicking pipettes in test tubes, and working in incubator rooms, cool rooms, warm rooms. Overhead, the sunlight strikes the vines and aloe plants on the shelves. The plants take in the summer light, each photon falling onto the surface of a microscopic, blob-shaped structure called a chloroplast. A chloroplast is essentially a solar-powered factory. It uses the energy of the light to manufacture new molecules out of raw materials such as carbon dioxide and water. The new molecules are trundled out of the chloroplasts and used by the plants to sprout new roots, to send out new feelers along the shelf. Below them, Roos’s students work furiously, discovering the hidden biochemistry of a parasite and publishing scientific papers, as if within them the sun were also driving some kind of intellectual photosynthesis. At a time like this, in a place like this, who has time to think about ancient history?