An old man with six fingers total saws lugubrious anthems of loss and love on a zither with a caved-in box and crooked plectrum. His only lyric: ¿por qué? repeated over and over like incantation. He sits on an old barber’s chair perched against a crumbling wall along one of the Zócalo walkways. He has breadcrumbs in his moustache, and the graffiti behind his sombrero’d head, reads, in Spanish: Fuck Your Mother. We drop a few sweaty coins into the empty yogurt dish at his feet. His eyes drop like bats feeding.

Vendors flash their wares. Leather wallets with big silver snaps. Purses of all sorts of hides bearing the ecstatic faces of the toothy gods, handbags made of tortoise shell and obsidian. Earrings of snail shells, snakeskin belts. Something about this commerce stirs in us a sly uneasiness, but admiration. This is a market without middleman, and the directness of it—the chance to place the pesos for a turtle purse into the durable hands of the man who, just last week, ripped the small wriggling body from the shell—is chilling, as it is alluring.

Like somnambulists, we zombify the market, wide-eyed and stiff-legged, not saying a word or looking at each other, Mexico City the only reaction shot we need. I want to know everything Louisa is thinking, if thoughts of Chicago evaporating like tea steam rush her with their thin whistle, if she is only in the moment or already forcing upon it reflection from some unknowable, but probable future. I want to know, but stare straight ahead until she speaks.

“I’d really like an agua fresca.

Her voice is like the hand that pulls me from the bottom of the pool, where I lost myself gathering pennies to the point of drowning; the same penchant for blind engrossment that caused me as a child to piss myself while watching Sesame Street. I suck air. It’s filthy and wonderful. All sewage and roasting corn.

“We have to find the kind that’s all fruit, or mixed with milk,” I say, “the ones mixed with water can hurt us.”

“It’s so tempting though,” she whines, gesturing to a stand mixing prickly pear drinks, cantaloupe, coconut, tamarind.

“Those are the water ones, baby,” I say, “Trust me, you don’t want to get sick.” And immediately I hate playing the role of reason, of lack of surrender, but I’ve been struck with parasites many times before; once, years ago in Mérida, Yucatán, when I couldn’t help but eat a guyaba berry rolled in chile powder, handed to me by a cloaked 100-year-old Mayan woman sitting streetside on a blue plastic crate. I paid for such surrender with high fever and higher intestinal duress for weeks, cut with no sleep and freezing cold sweats. It was only later that I found out that, in Taíno mythology, that the guyaba was typically reserved for opías, or the walking dead, who would parade the Ceiba forests and make of the berry the edible centerpiece for their night-feasts, taking the form of pale navel-less humans, or bats. In fact, according to the legend, the ruler of these dead bore the name of Maquetaurie Guayaba, Lord of Sweet Delight. The nectar of the berry was often used as the base of a black body paint used to evoke the nature of death in various rituals and rites. So, maybe that had something to do with it.

“Oh, I know,” Louisa croons as we pass the fruit drink stands, “but they look so good.”

Restraint, especially when it comes to ingestibles, when we’re traveling has thankfully never been our strong suit as a couple. But pass the stands we do. Soon, as if antidote, we’re looking to buy a knife from a short middle-aged man in a tank-top, serpentine scar tattoos adorning both of his shoulders, moustache guyaba berry-death paint-dark, straw sombrero ripped open at the top, exposing his wet knotted hair. Surely we need something sharp with which to excise our agua fresca loss. We make this transaction wordlessly. The scarred man shows us various knives—thick-bladed, thin-bladed, switch-bladed, stone. Bright knives inlayed with jewels, knives used and stained with old blood and rust. When we shake our heads, he retrieves a new one from its slumber on his crowded blanket. He is barefoot and his foot-tops bear old puncture wounds.

After seven failed attempts, he retrieves a stunning obsidian knife with an Aztec design carved handle of green onyx. It is ancient-looking and beautiful, fresh from some painful sacrifice—agua fresca or otherwise. This is the one. The eyeballs convince us; carved into the handle, they bug-out at us, hypnotic enough for Louisa, continuing our opera of silence, to grab my unscarred shoulder. The man sees this, nods, and immediately wraps the knife in bubble-wrap and scotch tape. We pay him the 150 pesos (about twelve bucks) without bargaining, he touches our scalps as if blessing us, his tepid hands the texture of hessian, and we move on to the section of city on the other side of the Zócalo, where we have not yet been. Stone knife safely sheathed in packing material, we stroll the streets, teeming with life and neighborhood, dollies overloaded with wares of all kinds—carpets, jugs, cow heads, clothing—small cars honking, open flatbeds rattling, bicycles swerving, barely navigating the madness of street stand and pedestrian. We think of that man and his zither, can’t decide whether everything or nothing we see answers his endless question of Why? We barely navigate this madness ourselves, oblivious to the rules, the imbroglio of smell and sound, looking for anything alive to eat.

From a certain perspective the human body is little more than a conduit or a tube, taking in and emitting in roughly equal measure.

It’s an elemental conception of human life that sees two reasonably balanced, opposite streams alternately feeding the organism essentials and sluicing away waste. It’s a perspective common to Chinese medicine and Hinduism (among other systems of esoteric thought), which makes it of heightened significance to the Indian city of Mumbai.

In Mumbai, the dividing line between the flow of ingress and egress is often so fine that the distinction is blurred. To a large extent, and for a large section of the population there is very little distinction at all.

People everywhere seem to be ingesting what has previously been passed and excreting almost to feed rather than to vent. The attitude to water supply and sewage in Mumbai has been so compromised by the demands of overpopulation and the environmental rigours of breakneck growth that its no wonder typhoid is rife in the slums. In a very real, and frightening sense, there’s a kind of Faustian toxic alchemy at work, switching the poles of ‘in’ and ‘out’, mixing the waters, crossing the streams.

A wet, vegetable smell, redolent of human vomit and loam wafts into the office. Workers immediately reach for the take-away menus. “Mmmm… Shall we order lunch, guys?” A sewage pipe is simply being de-blocked outisde the building. Reports abound of food poisoning from street food in the days when the sewers are exposed.

The bathroom I use in the home I recently rented a room in in Mumbai is separated from the kitchen of the family of four by a chipboard partition that doesn’t quite reach the outer wall. When I am sitting on the toilet and the lady of the house is frying, there’s the continual possibility of a fine mist of burning fat droplets fountaining over the wall to enliven early morning ablutions.

With a bit of effort, we could shake hands during our respective processes like the first excited penetrators of the Berlin wall. I wonder how the aromas emanating from my bathroom don’t enter the flavour of the delicious food she makes. If I leave a cut raw onion in a fridge with a pot of opened yoghurt, I can’t really complain if the stuff turns out tasting more like raitha than Müller Lite, now can I?

Years ago, a very dear friend of mine came up with an ingenious method of balancing the flows. He called it the ‘Shit/Weight Plan’.

According to this system, weight can be easily controlled, gained or lost through the judicious application of weighing scales at the two ends of the process. His theory was that if one only consumed an equal poundage to that amount dropped off, a steady weight would be maintained. If one troughed more than one sloughed, weight would be put on; if one dumped more than one scrumped then weight would be shed.

The domestic setup that my landlady and I have is ripe for a field test of the Shit/Weight Plan. If she pushes them far enough to her right, Sibyl and I could cut out the middle man and share the kitchen scales, one pan each; shouting the differentials to each other through the partition as we go.