The Periodic Table

by Primo Levi

  in which O is oxygen, C is carbon, H hydrogen, and N nitrogen. It is a pretty structure, isn’t it? It makes you think of something solid, stable, well linked. In fact it happens also in chemistry as in architecture that “beautiful” edifices, that is, symmetrical and simple, are also the most sturdy: in short, the same thing happens with molecules as with the cupolas of cathedrals or the arches of bridges. And it is also possible that the explanation is neither remote nor metaphysical: to say “beautiful” is to say “desirable,” and ever since man has built he has wanted to build at the smallest expense and in the most durable fashion, and the aesthetic enjoyment he experiences when contemplating his work comes afterward. Certainly, it has not always been this way: there have been centuries in which “beauty” was identified with adornment, the superimposed, the frills; but it is probable that they were deviant epochs and that the true beauty, in which every century recognizes itself, is found in upright stones, ships’ hulls, the blade of an ax, the wing of a plane.

  Having recognized and appreciated the structural virtue of alloxan, it is urgent that my chemical alter ego, so in love with digressions, get back on the rails, which is that of fornicating with matter in order to support myself—and today, not just myself. I turned with respect to the shelves of the Zentralblatt and began to consult it year by year. Hats off to the Chemisches Zentralblatt: it is the magazine of magazines, the magazine which, ever since Chemistry existed, has reported in the form of furiously concise abstracts all the articles dealing with chemistry that appear in all the magazines in the world. The first years are slender volumes of 300 or 400 pages: today, every year, they dish out fourteen volumes of 1,300 pages each. It is endowed with a majestic authors’ index, one for subjects, one for formulas, and you can find in it venerable fossils, such as the legendary memoir in which our father Wohler tells the story of the first organic synthesis or Sainte-Claire Deville describes the first isolation of metallic aluminum.

  From the Zentralblatt I ricocheted to Beilstein, an equally monumental encyclopedia continually brought up to date in which, as in an Office of Records, each new chemical compound is described as it appears, together with its methods of preparation. Alloxan was known for almost seventy years, but as a laboratory curiosity: the preparation method described had a pure academic value, and proceeded from expensive raw materials which (in those years right after the war) it was vain to hope to find on the market. The sole accessible preparation was the oldest: it did not seem too difficult to execute, and consisted in an oxidizing demolition of uric acid. Just that: uric acid, the stuff connected with gout, intemperant eaters, and stones in the bladder. It was a decidedly unusual raw material, but perhaps not as prohibitively expensive as the others.

  In fact subsequent research in the spick and span shelves, smelling of camphor, wax, and century-old chemical labors, taught me that uric acid, very scarce in the excreta of man and mammals, constitutes, however, 50 percent of the excrement of birds and 90 percent of the excrement of reptiles. Fine. I phoned the tough and told him that it could be done, he just had to give me a few days’ time: before the month was out I would bring him the first sample of alloxan, and give him an idea of the cost and how much of it I could produce each month. The fact that alloxan, destined to embellish ladies’ lips, would come from the excrement of chickens or pythons was a thought which didn’t trouble me for a moment. The trade of chemist (fortified, in my case, by the experience of Auschwitz) teaches you to overcome, indeed to ignore, certain revulsions that are neither necessary or congenital: matter is matter, neither noble nor vile, infinitely transformable, and its proximate origin is of no importance whatsoever. Nitrogen is nitrogen, it passes miraculously from the air into plants, from these into animals, and from animals to us; when its function in our body is exhausted, we eliminate it, but it still remains nitrogen, aseptic, innocent. We—I mean to say we mammals—who in general do not have problems about obtaining water, have learned to wedge it into the urea molecule, which is soluble in water, and as urea we free ourselves of it; other animals, for whom water is precious (or it was for their distant progenitors), have made the ingenious invention of packaging their nitrogen in the form of uric acid, which is insoluble in water, and of eliminating it as a solid, with no necessity of having recourse to water as a vehicle. In an analogous fashion one thinks today of eliminating urban garbage by pressing it into blocks, which can be carried to the dumps or buried inexpensively.

  I will go further: far from scandalizing me, the idea of obtaining a cosmetic from excrement, that is, aurum de stercore (“gold from dung”), amused me and warmed my heart like a return to the origins, when alchemists extracted phosphorus from urine. It was an adventure both unprecedented and gay and noble besides, because it ennobled, restored, and reestablished. That is what nature does: it draws the fern’s grace from the putrefaction of the forest floor, and pasturage from manure, in Latin laetamen—and does not laetari mean “to rejoice”? That’s what they taught me in liceo, that’s how it had been for Virgil, and that’s what it became for me. I returned home that evening, told my very recent wife the story of the alloxan and uric acid, and informed her that the next day I would leave on a business trip: that is, I would get on my bike and make a tour of the farms on the outskirts of town (at that time they were still there) in search of chicken shit. She did not hesitate; she likes the countryside, and a wife should follow her husband; she would come along with me. It was a kind of supplement to our honeymoon trip, which for reasons of economy had been frugal and hurried. But she warned me not to have too many illusions: finding chicken shit in its pure state would not be so easy.

  In fact it proved quite difficult. First of all, the pollina—that’s what the country people call it, which we didn’t know, nor did we know that, because of its nitrogen content, it is highly valued as a fertilizer for truck gardens—the chicken shit is not given away free, indeed it is sold at a high price. Secondly, whoever buys it has to go and gather it, crawling on all fours into the chicken coops and gleaning all around the threshing floor. And thirdly, what you actually collect can be used directly as a fertilizer, but lends itself badly to other uses: it is a mixture of dung, earth, stones, chicken feed, feathers, and chicken lice, which nest under the chickens’ wings. In any event, paying not a little, laboring and dirtying ourselves a lot, my undaunted wife and I returned that evening down Corso Francia with a kilo of sweated-over chicken shit on the bike’s carrier rack.

  The next day I examined the material: there was a lot of gangue, yet something perhaps could be gotten from it. But simultaneously I got an idea; just at that time, in the Turin subway gallery an exhibition of snakes had opened: Why not go and see it? Snakes are a clean species, they have neither feathers nor lice, and they don’t scrabble in the dirt; and besides, a python is quite a bit larger than a chicken. Perhaps their excrement, at 90 percent uric acid, could be obtained in abundance, in sizes not too minute and in conditions of reasonable purity. This time I went alone: my wife is a daughter of Eve and doesn’t like snakes.

  The director and the various workers attached to the exhibition received me with stupefied scorn. Where were my credentials? Where did I come from? Who did I think I was showing up just like that, as if it were the most natural thing, asking for python shit? Out of the question, not even a gram; pythons are frugal, they eat twice a month and vice versa; especially when they don’t get much exercise. Their very scanty shit is worth its weight in gold; besides, they—and all exhibitors and owners of snakes—have permanent and exclusive contracts with big pharmaceutical companies. So get out and stop wasting our time.

  I devoted a day to a coarse sifting of the chicken shit, and another two trying to oxidize the acid contained in it into alloxan. The virtue and patience of ancient chemists must have been superhuman, or perhaps my inexperience with organic preparations was boundless. All I got were foul vapors, boredom, humiliation, and a black and murky liquid which irremediably plugged up the filters and displayed no tend
ency to crystallize, as the text declared it should. The shit remained shit, and the alloxan and its resonant name remained a resonant name. That was not the way to get out of the swamps: by what path would I therefore get out, I the discouraged author of a book which seemed good to me but which nobody read? Best to return among the colorless but safe schemes of inorganic chemistry.

  TIN

  It’s bad to be poor, I was brooding as I held an ingot of tin from the Straits over the flame of the gas jet. Very slowly the tin melted, and the drops fell with a hiss into the water of a basin: on the basin’s bottom a fascinating metallic tangle of ever new shapes was forming.

  There are friendly metals and hostile metals. Tin was a friend—not only because, for some months now, Emilio and I were living on it, transforming it into stannous chloride to sell to the manufacturers of mirrors, but also for other, more recondite reasons: because it marries with iron, transforming it into mild tin plate and depriving it on that account of its sanguinary quality of nocens Jerrum; because the Phoenicians traded in it and it is to this day extracted, refined, and shipped from fabulous and distant countries (the Straits, precisely: one might say the Sleepy Sonda Islands, the Happy Isles and Archipelagos); because it forms an alloy with copper to give us bronze, the respectable material par excellence, notoriously perennial and well established; because it melts at a low temperature, almost like organic compounds, that is, almost like us; and finally, because of two unique properties with picturesque, hardly credible names, never seen or heard (that I know) by human eye or ear, yet faithfully handed down from generation to generation by all the textbooks—the “weeping” of tin and tin pest.

  You have to granulate tin so that afterward it can be easier to attack with hydrochloric acid. So you asked for it. You were living under the wings of that lakeshore factory, a bird of prey but with broad, strong wings. You decided to get out from under its protection, fly with your own wings: well, you asked for it. So fly now: you wanted to be free and you are free, you wanted to be a chemist and you are one. So now grub among poisons, lipsticks, and chicken shit; granulate tin, pour hydrochloric acid; concentrate, decant, and crystallize if you do not want to go hungry, and you know hunger. Buy tin and sell stannous chloride.

  Emilio had managed to carve a lab out of his parents’ apartment, pious, ill-advised, long-suffering people. Certainly, when they let him take over their bedroom, they had not foreseen all the consequences, but there’s no way back: now the hallway was a storeroom jammed with demijohns full of concentrated hydrochloric acid, the kitchen stove (outside of mealtime) was used to concentrate the stannous chloride in beakers and six-liter Erlenmeyer flasks, and the entire apartment was invaded with our fumes.

  Emilio’s father was a majestic, benign old man with a white mustache and a thunderous voice. He had had many different trades during his life, all adventurous or at least odd, and at seventy he still had a preoccupying avidity for experimentation. At that period he held the monopoly of the blood of all the cattle slaughtered at the old Municipal Slaughterhouse on Corso Inghilterra: he spent many hours of the day in a filthy cavern, its walls brown from dried-up blood, its floor soaked with putrefied muck, and frequented by rats as large as rabbits; even his invoices and ledgers were stained with blood. The blood was turned into buttons, glue, fritters, blood sausages, wall paints, and polishing paste. He read exclusively Arabic newspapers and magazines, which he had sent from Cairo, where he had lived many years, where he had had three sons, where he had defended, rifle in hand, the Italian Consulate from an enraged mob, and where his heart remained. He went every day on his bicycle to Porta Palazzo to buy herbs, sorghum flour, peanut fat, and sweet potatoes: with these ingredients and the slaughterhouse blood he cooked experimental dishes, a different one each day; he bragged about them and made us taste them. One day he brought home a rat, cut off its head and paws, told his wife that it was a guinea pig, and had her roast it. Since his bicycle did not have a guard over the chain and the small of his back had become a bit stiff, he would put clips on the cuffs of his pants in the morning and wouldn’t take them off all day. He and his wife, the sweet and imperturbable Signora Ester, born in Corfu of a Venetian family, had accepted our laboratory in their house, as if keeping acids in the kitchen was the most natural thing in the world. We would carry the demijohns of acid to the fourth floor in the elevator; Emilio’s father looked so respectable and authoritative that no tenant dared object.

  Our laboratory looked like a junk shop and the hold of a whaler. Apart from overflows that, as I said, invaded the kitchen, the hallway, and even the bathroom, the lab consisted of a single room and the terrace. On the terrace were scattered the parts of a DKW motorcycle which Emilio had bought dismantled and which, he said, he would put together again someday; the scarlet gas tank was perched on the railing, and the motor, inside a fly net, rusted away, corroded by our exhalations. There were also some tanks of ammonia left over from an epoch preceding my arrival, during which Emilio made ends meet by dissolving gaseous ammonia in demijohns of potable water, selling them, and befouling the neighborhood. Everywhere, on the terrace and inside the apartment, was scattered an incredible amount of junk, so old and battered as to prove almost unrecognizable: only after a more attentive examination could you distinguish the professional objects from the domestic ones.

  In the middle of the lab was a large ventilation hood of wood and glass, our pride and our only protection against death by gassing. It is not that hydrochloric acid is actually toxic: it is one of those frank enemies that come at you shouting from a distance, and from which it is therefore easy to protect yourself. It has such a penetrating odor that whoever can wastes no time in getting out of its way; and you cannot mistake it for anything else, because after having taken in one breath of it you expel from your nose two short plumes of white smoke, like the horses in Eisenstein’s movies, and you feel your teeth turn sour in your mouth, as when you have bitten into a lemon. Despite our quite willing hood, acid fumes invaded all the rooms: the wallpaper changed color, the doorknobs and metal fixtures became dim and rough, and every so often a sinister thump made us jump: a nail had been corroded through and a picture, in some corner of the apartment, had crashed to the floor. Emilio hammered in a new nail and hung the picture back in its place.

  So we were dissolving tin in hydrochloric acid: then the solution had to be concentrated to a particular specific weight and left to crystallize by cooling. The stannous chloride separated in small, pretty prisms, colorless and transparent. Since the crystallization was slow, it required many receptacles, and since hydrochloric acid corrodes all metals, these receptacles had to be glass or ceramic. In the period when there were many orders, we had to mobilize reserve receptacles, in which for that matter Emilio’s house was rich: a soup tureen, an enameled iron pressure cooker, an Art Nouveau chandelier, and a chamber pot.

  The morning after, the chloride is gathered and set to drain: and you must be very careful not to touch it with your hands or it saddles you with a truly disgusting smell. This salt, in itself, is odorless, but it reacts in some manner with the skin, perhaps reducing the keratin’s disulfide bridges and giving off a persistent metallic stench that for several days announces to all that you are a chemist. It is aggressive but also delicate, like certain unpleasant sports opponents who whine when they lose: you can’t force it, you have to let it dry out in the air in its own good time. If you try to warm it up, even in the mildest manner, for example, with a hair dryer or on the radiator, it loses its crystallization water, becomes opaque, and foolish customers no longer want it. Foolish because it would suit them fine: with less water there is more tin and therefore more of a yield; but that’s how it is, the customer is always right, especially when he knows little chemistry, as is precisely the case with mirror manufacturers.

  Nothing of the generous good nature of tin, Jove’s metal, survives in its chloride (besides, chlorides in general are rabble, for the most part ignoble by-products, hygroscopic, not good
for much: with the single exception of common salt, which is a completely different matter). This salt is an energetic reducing agent, that is to say, it is eager to free itself of two of its electrons and does so on the slightest pretext, sometimes with disastrous results: just a single splash of the concentrated solution, which dripped down my pants, was enough to cut them cleanly like the blow of a scimitar; and this was right after the war, and I had no other pants except my Sunday best, and there wasn’t much money in the house.

  I would never have left the lakeshore factory, and I would have stayed there for all eternity correcting varnishes’ deformities, if Emilio had not insisted, praising adventure and the glories of a free profession. I had quit my job with absurd self-assurance, distributing to my colleagues and superiors a testament written in quatrains full of gay impudence: I was quite aware of the risk I was running, but I knew that the license to make mistakes becomes more limited with the passing of the years, so he who wants to take advantage of it must not wait too long. On the other hand, one must not wait too long to realize that a mistake is a mistake: at the end of each month we did our accounts, and it was becoming ever more obvious that man does not live by stannous chloride alone; or at least I did not, since I had just married and had no authoritative patriarch behind me.

  We didn’t surrender right away; we racked our brains for a good month in an effort to obtain vanillin from eugenol with an output that would permit us to live, and didn’t succeed; we secreted several hundred kilos of pyruvic acid, produced with equipment for troglodytes and a work schedule for slaves, after which I hoisted the white flag. I had to find a job, even if it meant going back to varnishes.