VIBES
READING TIME: 6M 2S
We leave traces of ourselves wherever we go, on whatever we touch. One of the odd discoveries made by small boys on exploring ventures around the house is that utility meters, the electrics and the gas, can be lifted free of the wall on a couple of long nails and gently turned around so that the dials rotate in reverse. It is a simple matter, for example, to make an electric meter run backwards, and for a while it is interesting to consider the consequences, a long cool silent summer, with fans blowing chill air and the whole house nice and dim with the lights left on all day and all night, and then one day to be paid by the electric company for all the good electricity we have put back into the grid. Then the meters get hot. The soft coat of dust behind them is revealed, itself a surprise, and is baked and blistered from the heat of the coils, and then it begins to smell like a strand of hair caught in a candle flame and soon the meter will not fit back onto the nails and the dials cannot be read and there is an elemental panic and the hands get smeared with a black powder, a hint or two of soot is left on the wall, specks of it on the roll of paper in the electric meter, and it is best to run and not return to the scene. Best not to try again. The first experiment is the only one, and the whole affair remains forever, to a few of us, as the experience of our first good scientific mystery. We cannot understand how it happened. We were careful. The meter could almost be turned back fast enough to avoid the overheating. The little boys who tried this became persons at that moment, caught out in the open by the traces left by their fingers, and for the rest of their lives they could never walk through a room without checking to see if they were leaving anything anywhere that could possibly be later touched by the hand again before being struck.
An intelligent dog with a good nose can track a man across open country, following his scent over the bare ground for distances of several miles. It surprises me that we do not feel required to take such facts into account as we tour around, but we are given, now and then, more subtle reminders. We rarely touch each other, now, I suppose we have all adopted a manner of courteous spacing between ourselves, but there are still places where we are forced to touch, where our bodies graze each other inadvertently, where we leave traces of ourselves on the backs of chairs and on the arms of people, and on the rails we grasp together in the subways. There is no doubt that this will be demonstrated scientifically, if it has not been done already, and I am resigned to the notion that someday the forensic laboratories will have the means of making precise identifications of persons from the scent left by a hand upon a doorknob, even if the hand were washed and dried before it arrived, and whether the doorknob were gripped by the hand for a short time or a long time. The odds are high that they will be able to make us out from each other as though they were made by the same man.
We are marked as self by the chemicals we leave beneath the surface of our skins and on our clothes; these include the small fatty acids derived from the bacterial breakdown of epidermal lipids, among a number of other similar compounds. Some at least are left in our clothing, and some remain in the surface antigens detectable in homografts of our tissues.
Other animals are similarly endowed with signaling mechanisms of their own, and in some instances, the messages are so vivid that we can pick them up easily; there are aggressive odors from swine, and distinctive odors from goats and other domestic animals, as well as panic odorants that throw them into disorganized panic.
Minnows and catfish can recognize each member of their own species, and individuals within their specific schools, by signals emitted into the water. Their ability to home to specific streams has often been remarked upon, but it is only recently that the role of olfactory signals in this behavior has been examined carefully. It is possible to train salmon to respond specifically to the tiniest differences in the ionic composition of waters, and there is evidence that each stream may bear a signature of its own, detectable by the salmon on returning to their grounds, whereas water from other streams causes no response.
We feel somehow inferior and left out of things by all the marvelous performances of our biochemical world. We used to think of ourselves as superior beings because of our large brains and our talent for language and music and painting, but nowadays, compared with the rest of the living creatures, we seem relatively poorly endowed. Perhaps we are designed to survive and to accomplish our work by engaging our brains on subtle and abstract matters, rather than by acquiring marvelous instruments for sniffing the environment. When our children are found to have their hands on their noses and their noses to the ground, it seems to me that our reaction is not admiration, but a kind of alarm, and we begin to think of the children as though they were elderly, dotty relatives in need of hobbies.
But we may be better at it than we think. An average man can identify about ten thousand different odors, and women are likely to be better at sniffing. We can sense differences among certain chemicals as low as the tenth power of the molar value, and we can distinguish among mixtures of various oils, perhaps not very acutely, but with enough skill to enable us to make perfumes. It is not only the perfumes that are notable for their richness of composition, but the odors of ordinary things, such as greases, which may be mixtures of many different hydrocarbons, with one or two sulfur compounds, and the smell of the ground up pismires, for which the great word pismire was originally coined.
There may even be odorants that fire off receptors in our olfactory mucosa and convey messages in a manner quite beyond our present reach of understanding. We have evidence that certain people who are studied closely can distinguish, by smell alone, one person from another. There is a report that some individuals can even tell monozygotic twins apart by smell, and there is evidence that women can distinguish differences in odor associated with the phase of the menstrual cycle, and there is a peculiar fact about the ability of some dogs to detect single human beings. In some instances, the sensitivity of the dogs seems to be related to trans-3-methylhexenoic acid, in their sweat.
Olfactory receptors for communication between different creatures are far more complex and precise than we imagined, and are never limited to single molecules; it is always a matter of complex blends. We have much to learn, and I think it will be a long time before we know enough to understand what messages are being sent by the olfactory secretions of our own species. We may turn out to be more of a problem, when we start studying our own secretions, than we are worth, but it is an experiment worth doing, if it can be done carefully, with proper controls, so as not, on the one hand, to get the romantics running away with the data, and on the other hand, to keep the latter from getting out of hand.
A very general system of chemical communication between living things appears to be in operation around us, on a global scale, for the homeostatic regulation of the biosphere. If this is true, it would provide a new dimension to ecology. We are not bystanders; by our chemical messages we are participants in the scene, evidently designed for the homeostasis of the earth.
Jorge Borges, in his recent bestiary of mythical creatures, notes the existence of beings who can communicate with each other by scent alone, passing messages without language or sound. If he is right, we may someday find that we can accomplish similar messages between all kinds of other creatures.
This is an interesting kind of problem, made to order for computer people. It is an exceedingly difficult problem, because we are in the habit of separating things that may be continuous in nature, and we give them separate names and study them as though they were different things. We shall surely need machines more complicated than any we have today to solve this problem, and I wonder if we will ever find enough graduate students.
— LEWIS THOMAS (1913–1993), THE LIVES OF A CELL, NOTES FROM A BIOLOGY WATCHER, “VIBES” PP 37–41, PENGUIN BOOKS, 1974.