As the oysters lie there, raw, moist, tender and glistening, in their half-shell, waiting to be devoured, it is easy to conjure up erotic associations, to which many authors have drawn attention. To paraphrase a comment passed by Rebecca Stott in her book Oyster, ”eat oysters and try not to think of sex” (2004, 170). And what better animal is there to be bestowed with aphrodisiac qualities than the hermaphrodite oyster, as it changes sex back and forth for the betterment of its own species? Once the baby oyster has found somewhere to settle after its 2 or 3 weeks of floating freedom, it’s stuck there for life. The life of attachment it leads could be the envy of many humans, some of whom never achieve such a feat. However, it will never be wooed nor courted and the only visitor or suitor it is likely ever to entertain is one with evil intent – a predator, waiting to get into its insides and eat it. So in its state of complete solitude, like many of its other sessile cousins, its only sexual activity possible (and hopefully enjoyment) is to play around with itself. And that it does, in a truly amazing way! Moreover, both the common genera of Ostrea and Crassostrea oysters have their own way of changing sex, of growing female and/or male gametes, which they do so as the summer seas start to warm up. Though to be fair, they are never desperate enough to mate with themselves. No, they release either their eggs or their sperm, but never both at the same time, which shows just how ingenious Oyster Nature is. Whereas the female of the Ostrea genus incubates the fertilised eggs inside her shell for about 10 days before expelling them into the open sea, the male and female members of the Crassostrea genus spawn directly into the open water column, possibly because they tend to inhabit warmer seas.

Ever since Roman times, we have written sources that claim the sexual potency of the oyster. Imperial orgies were never complete without provisions of oysters in their thousands. Galen of Pergamon (129-199), possibly the most accomplished physician of all antiquity, prescribed oysters as a cure for declining sexual desire. During the Middle Ages, it was generally known that the oyster “exciteth Venus”- and so on throughout history and literature. There was even a Victorian underground magazine of erotica, published in the 1880’s, called The Oyster, and devoted to more heterosexual material than its predecessor, The Pearl. So it was no small wonder that the poor country girls, the oysterwenches who stalked the streets of the growing cities, hawking their wares, were often regarded as prostitutes.

But even in earlier societies, there has been overwhelming evidence of the magical beliefs in shells, as the resemblance between the mollusc shell and the female genital organ helped spawn associations. As Mircea Eliade, the famous historian of religions, wrote “belief in the magical virtues of oysters and of shells is to be found all over the world, from prehistoric until modern times” (1952/1961, 125). Mollusc shells, in particular, seem to have been associated with fertility, and were a valued gift and amulet to girls on reaching puberty. They have been found in places connected with agricultural, nuptial and funerary rites, and symbolised the magical powers of the womb, of birth and rebirth. And the Greek legend of the birth of Aphrodite, the goddess of love, from a shell (often mistaken for an oyster’s but in fact more a scallop’s) in the foam of the sea is a metaphor for the same belief. So this symbolism of mollusc shells is the first part of the aphrodisiac equation of the oyster. As with other aphrodisiacs like avocados, figs, asparagus, bananas, or nuts, because of their appearance or form, we naturally succumb to the temptation to follow the paths of our associations and jump from the idea of fertility enhancers to substances that arouse sexual excitement.

In this context, the name of Giacomo Casanova faithfully rears its head and his own (be it probably all too partial) description (volume 12 of his Histoire de ma vie [Story of my Life], chapter 2, 54-57) of eating his beloved oysters in female company deserves to be quoted in full, as he and his insatiable appetite for oysters are so often taken for granted. In these memoirs of his, most mentions of oysters refer to social gatherings where he is entertained and plied with platefuls of them. But on this special occasion, he is in Rome, amongst friends; it’s 1771 (more than 20 years before he wrote his memoirs) and after an evening at the opera with Armellina and Emilia, two young women from a convent whom he has got to know through common acquaintances, has ordered oysters, rum and champagne in the private rooms of an inn and is introducing them to his “oyster game”, one of his ways of enjoying them:

“I put the shell to her [Emilia’s] mouth, I told her to suck in the liquid and keep the oyster between her lips. She performed the feat to the letter after laughing heartily, and I took the oyster by pressing my lips to hers with the greatest decency. She was delighted by the delicacy with which I took the oyster from her lips…….It was by chance that a fine oyster which I gave Emilia, putting the shell to her lips, dropped into her bosom; she made to recover it, but I claimed that it was mine by right, and she had to yield, let me unlace her, and gather it with my lips from the depth to which it had dropped. In the course of this she had to bear with my uncovering her bosom completely; but I retrieved the oyster in such a way that there was no sign of my having felt any pleasure except that of having recovered, chewed and swallowed it. Armellina watched the whole procedure without smiling, surprised that I appeared to show no interest in what I had seen. Four or five oysters later I gave one to Armellina, who was sitting on my lap, and I cleverly dropped it into her bosom, which brought a laugh from Emilia, who at bottom was annoyed that Armellina had escaped a test of an intrepidity such as she had shown me. But I saw that Armellina was delighted by the mishap, though she refused to give any sign of it.

“I want my oyster,” I said.

“Take it.”

I unlaced her whole bodice, and, the oyster having dropped as far down as possible, I complained that I would have to bring it up with my hand. Good God! What torment for a man in love to have to hide the excess of his delight at such a moment! Armellina had not the slightest pretext to accuse me of anything, for I did not touch her beautiful breasts, hard as marble, except in searching for the oyster. After retrieving and swallowing it, I took hold of one of her breasts, demanding the liquid from the oyster which had spilled on it; I seized the rosebud with my avid lips, surrendering to all the voluptuous feelings inspired in me by the imaginary milk which I sucked for a good two or three minutes.”

However tempting this may indeed seem, it can hardly be recommended form in a public oyster bar or restaurant! On the other hand, there are many accounts from both males and females of their very first taste of oysters, often in the company of their fathers, almost as if they had been initiated into a sexual rite of passage, and lost their virginity, or at least their childhood innocence. One such appealing narrative, with a twist, can be found in Hector Bolitho’s book The Glorious Oyster (1929).

Stott wrote in the prologue to her book, “as a sea creature, it is quintessentially alien to the human form and to human experience” (p. 10): but it is just this alienation, the encounter with “not-me”, that fires our fantasy and stirs a primeval sense of recognition – almost atavistic, as though in that flash we are emerging from our own aquatic (inter-uterine) existence – of the resemblance of oyster flesh with the lips of female genitalia, similar to a freshly-opened sweet fig. Indeed, the oyster has wormed its way into urban slang as another word for “pussy”. Moreover, on a deeper level, there may be a subliminal realisation of human-animal kinship and of our own primordial, aquatic existence that takes on an almost evanescing quality which turns the binary opposites of raw and cooked, of land and sea, of savage and cultured and of revulsion and rapture into turmoil and allows the open “sore” of flesh assume sexual meaning, in our attempt to reclaim some guise of order.

This leads quite naturally to the burning question of why as such are oysters an aphrodisiac. For, they are nowadays hardly the fare of everyday life, as they were in the 19^th century; they are eaten on special occasions, at festive moments. Moreover, although belief in the aphrodisiac quality of oysters has survived throughout history and in various cultural contexts, the power of shared fantasies, however mythic, performs a self-fulfilling function and as humans we are suckers for the placebo effect! This embraces many of our belief structures, as the more appeal a belief carries, the more embedded it becomes. So here is another element in the notion, which we no doubt celebrate every time we decide to eat oysters. These social and psychological factors are potent in themselves, but there seems as if there are other more biochemical explanations, which tend to support the oyster’s claim to fame. Because of the similarity of the oyster’s own developed anatomy to very early stages of the human fertilised egg, much of the oyster’s constitution is reflected in those chemicals needed for reproduction and fertilisation. And it is possible for the wild oyster during early summer to convert up to 75% of its flesh into male or female gametes, so that in some sense it may be considered a highly charged and sophisticated egg, or spawning machine.

As regards the protein content in the oyster, which amounts to 9-10% of 100g of meat and is equivalent to a fifth of the RDA for a normal sized adult, like all shellfish, it consists of every one of the nine essential amino acids that the body, as it cannot synthesise them itself, needs to obtain from food, and also several of the non-essential amino acids (alanine, arginine and glycine, which the human body produces) and which are the building blocks of protein. Another interesting point to stress is the relatively high level found in oysters of both aspartic acid and glutamic acid, two more non-essential amino acids and two of the most common excitatory neurotransmitters, which may seem also to account partly for the taste of umami. In addition, in its relatively simple nervous system and its gills, the oyster does contain both significant amounts of serotonin and dopamine, another two vital neurotransmitters. Even more intriguing, according to Italian and American researchers working on the neurochemistry of amino acids, is the occurrence in oysters and other bivalve molluscs of an even rarer amino acid, crucial for neurosynaptic efficiency, N-methyl-D-aspartate (NMDA). This also plays a role in the induction of the gonadotropin-releasing hormone in the hypothalamus and lutropin in the pituitary gland, both of which stimulate ovulation and help to produce progesterone in females and testosterone in males, thereby enhancing the libido. A boring caveat is that oral digestion of such acids does not always lead to the release of enough sex hormones really to matter. Even the considerable presence of omega-3 fats and another of the non-essential amino acids, arginine, has beneficial effects on bloodflow and general well-being. And if the huge amount of zinc, present particularly in oysters, is taken also into account, and which is well known as an important factor also in the function of the pituitary gland and testosterone production, then it is possible to discern very good grounds for the assertion that oysters are indeed an aphrodisiac, or as near as can be! At least they try their best in more ways than one!