1 Our Relationship with the Snail
So attached was the author Patricia Highsmith to snails that they became her constant travelling companions. Secreted in a large handbag or, in the case of travel abroad, carefully positioned under each breast, they provided her with comfort and companionship in what she perceived to be a hostile world.1
Theirs was an unusual relationship: one normally reserved for a dog or a cat. For most human beings just the mention of the word snail brings out a negative response; certainly not warmth or affection or a desire to share living space. It seems as though the relationship we have with this animal has been influenced by the harm it has inflicted over the years on our cabbage crops, strawberries and garden seedlings. Britain is a nation of gardeners and doesn’t take kindly to animals that threaten that pastime. Try looking at the shelves of any bookshop for a volume on snails that is complimentary to them and you will be disappointed. The language is often heated and full of military metaphors. ‘Understand the enemy as a first step to banishment’, says one, while another urges us to ‘stop them in their tracks with a barrier or a trap’. The Royal Horticultural Society makes slugs and snails the number one pest. Andrew Holgate, writing for the Sunday Times in a piece appropriately entitled ‘Hostas at Dawn – Showdown in the Garden’, singles them out as the worst offenders in the garden and amongst the most unpleasant of the creatures to be found there. America is similarly unimpressed by slugs and snails. There they have been described as ‘fun to hate, easy to kill, but maddeningly difficult to control’.2 While the majority of gardeners would agree with these sentiments, Steve Jones, an acknowledged snail expert, is of the opinion that snails aren’t just beautiful creatures that deserve our respect, but efficient machines capable of turning grass into flesh. He points out that while it takes at least five pounds of high-quality grain to make a pound of beef, snails are known to be twice as efficient on a much feebler diet. Instead of being our enemies, they should be our servants, providing food for hungry mouths.3
Our response to the snail is rarely one of indifference, especially seeing its body fully extended. This example is Helix algira, from Dupuy’s 1848 Histoire Naturelle des Mollusques.
For my own part, the relationship with the snail started when I was young, staying at my aunt’s house perched precariously on a Welsh hillside. I remember them emerging, as if by magic, on the stone steps leading down to the river after a shower of rain. To this day I associate the smell of wet concrete and coal dust with Helix aspersa, the common garden snail. Only later did I realize that the majority of land snails were much smaller and less conspicuous than these well-fed creatures. My curiosity quickly extended to sea snails when, like Eustace in L. P. Hartley’s Shrimp and the Anemone, I would stare for hours into rock pools and become drawn in to the secret world of winkles, limpets and top shells. The discovery of snails in ponds and streams advanced the relationship one step further and made me realize what a diverse group of animals I was witnessing.
Though I was never tempted to keep snails as pets, as I believe Beatrix Potter did, and certainly never achieved the affinity for them that Patricia Highsmith enjoyed, I was surprised to read the depiction of snails as rather sinister, far from comforting, creatures in two of Highsmith’s short stories.4 In the first, ‘The Snail-Watcher’, snails are responsible for the macabre death of the man who bred them. Locked in his laboratory, layers deep in snails, he finds himself unexpectedly overwhelmed:
Mr Knoppert tried to brush the snails off his arms. But for every hundred he dislodged, four hundred seemed to slide upon him and fasten to him again, as if they deliberately sought him out as the only comparatively snail-free surface in the room. There were snails crawling over his eyes . . . he swallowed one . . . choking, he widened his mouth for air and felt a snail crawl over his lips on to his tongue. He was in hell! He could feel them gliding over his legs like a glutinous river, pinning his legs to the floor.
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Rock pools offer man a place for contemplation. For dog whelks, they are a hunting-ground for food – here, the barnacles affixed to weedfree rocks. |
In the second, ‘The Quest for Blank Claveringi’, Avery Clavering, a professor of zoology, encounters a giant snail on the uninhabited island of Kuwa. As the two draw near to one another, the snail lifts its head in a menacing way and the professor gets more than he bargains for:
The professor angrily flung handfuls of water at the snail’s face. The snail only lifted its head higher, out of the professor’s range. Its form was slender now, and it had, oddly, the grace of a horned gazelle, of some animal of the deer family. The snail lowered its snout, and the professor trudged away, but not quickly enough: the snail came down on his shoulder and the suctorial mouth clamped . . . He realised as the thousands of pairs of teeth began to gnaw at his back, that his fate was both to drown and to be chewed to death.
The idea of a snail as a human aggressor sounds like revenge for all those hostile acts committed by man on the animal. Maybe it was Highsmith’s way of redressing the balance. There is no doubt that inflating the size of the snail or imagining overwhelming numbers of the creatures can make you shudder, but transpose the snail to a watery environment and the threat recedes. Snails that live in water, despite being sometimes larger than those that live on land, are undoubtedly far less threatening. I can find only one reference to a murderous sea snail on film in The Monster that Challenged the World (1957) and the reviews suggest it was rather unconvincing.5
Far from being threatening, sea snails such as whelks and winkles have provided man with welcome food for aeons. Their shells epitomize the sea and many are collected for their sheer beauty. As Peter Dance, a world authority on shells and shell collecting, points out, the spirally twisted shell of the sea snail has more appeal to the collector than that of the hinged bivalve shell.6 It might be thought that snails found on land and in freshwater would have less appeal, but even as far back as the seventeenth century many of their shells were thought desirable.7 The appeal of land snails as food was and is more variable, much of it culturally determined. Mary Fisher, the food writer, once described herself as being ‘dizzy for days’ after eating enough land snails in Dijon to make her feel she had ‘old rubber boiled in garlic’ inside her. The experience didn’t put her off eating them again, however. ‘I like snails’, she quipped defensively, ‘After all, most people like snails!’8 She was, I suspect, reflecting a French, gastronomic view of land snails, not one shared by the inhabitants of Great Britain. When it came to slugs, Mary Fisher’s attitude proved quite different:
I have tried to be callous about slugs. I have tried to picture the beauty of their primeval movements before a fast camera, and I have forced myself to read in the Encyclopaedia Britannica the harmless ingredients of their oozy bodies. Nothing helps. I have a horror deep in my marrow, of everything about them. Slugs are awful; slugs are things from the edges of insanity.9
Slugs have been described as ‘impossible land animals’ because they have a high water content but a permeable skin. Despite this, they are very successful and the leopard slug (Limax maximus) is one of the largest around.
In zoological terms, slugs are merely snails that have lost their shells, a process that has occurred on several occasions in the course of evolution. While numerous recipes exist for snails, virtually none exists for slugs. Most people show an aversion to picking up a slug; few are averse to picking up a snail. The distinction between the two may be a narrow one, but the human response is fundamentally different.
The reason, I believe, lies in the distinction we make between snail body and snail shell. The safe, non-aversive bit is undeniably the shell, particularly if empty or fragmented; the unsafe, potentially revolting bit is the soft body, revealed in its fullest extent in the slug. Though the shell is the product of the body, secreted by its covering or mantle, the two are usually seen as being unconnected, as though a living animal occupies an otherwise empty shell. As one writer put it:
It comes as a shock to many people that an animal is involved at all; their surprise always comes as a shock to me. These are the moulded-by-waves theorists who believe that shells are actually mineral deposits or the calcified remains of vegetation. They repeat ‘animal’ numbly after me, obviously visualising something with four legs and a tail, totally lost. It is hard for some people to think of a snail as an animal, but then it is hard for some people to classify themselves in that category.10
We are conditioned to think of the snail as an animal that uses its shell solely for protection, in much the same way that a hermit crab uses an empty mollusc shell as a refuge. It comes as a surprise that as the body of the animal grows the shell enlarges as well. Rather than being shed, like a snake’s skin when it gets too small, the snail shell is simply added to, preserving its shape. Some of the earliest drawings of snails, such as those from Hortus Sanitatis in the sixteenth century, show the occupant’s head peeping out from a protective tube as though it has just found shelter.11
It is with reference to the shell alone that early classifications of snails were based and, as if to emphasize this distinction between the hard and soft parts, students of snails are designated either conchologists, those who are primarily interested in the shell, or malacologists, whose main interest is in the soft body.
These early woodcuts (from Hortus sanitatis, c. 1511) suggest snail shells could be occupied by some unusual creatures.
This 2003 Cuban stamp shows a tree snail local to the island (Polymita picta). Known as the ‘painted snail’, it has numerous coloured varieties.
When considering our relationship with the snail, it seems that there is an unconscious need to keep the two bits apart, rather than countenance one, integrated creature. Following this line of thought, I wish to consider man’s relationship with the snail’s shell, then with its body and the products of that body, before re-examining the relationship with the animal as a whole.
MAN AND SHELL
Shells have proved irresistible to man because of their colour and variety. Man’s search for the colourful and the collectable inevitably brought him into contact with marine snails but also with tropical land snails, particularly those found on the Pacific islands. Early in the nineteenth century, visitors to the island of O‘ahu in the Hawaii archipelago noted that on shaking the trees, instead of insects falling on their heads, brightly coloured snails rained down on them. These tree snails were called pupukanioe by the natives, meaning ‘the shell that sounds long’, because they appeared to sing as they crawled over the foliage.12 I say ‘appear’ because they have no sound-producing apparatus and the probable source of the sound is a tree cricket. Colonies of these snails remained in a single locality, sometimes a single tree, for generations and this isolation over long periods of time encouraged the formation of new species. The result was a diverse population of colourful snails. This state of affairs was repeated on other Pacific islands. Each island ended up with its own endemic species so that one renowned conchologist, William Clench, once remarked that if transported blindfold to any tropical Pacific island and shown the shells of the land snails that lived there, he would be able to work out exactly where he was from their colour and patterning.13 So attractive were these island shells that it wasn’t long before the early explorers were shipping home vast quantities to satisfy an acquisitive urge on the part of collectors in Europe. The most diverse population of land snails was found on the islands of Hawaii. Over 99 per cent of the 750 species there were endemic. The same was true in Samoa, where two thirds of the species of land snail were found nowhere else, the remaining third being found on neighbouring islands such as Fiji and Tonga. This pattern was repeated again and again throughout the Pacific.
From the 1920s onwards surveys of these oceanic islands were conducted in which each island’s land snail population was estimated. What they showed was that throughout the twentieth century there was a decline in the number of native species and a corresponding rise in the number of non-native species of snail. Of the introduced species, most had spread to displace the native species from their own habitats, resulting in a homogenization of Pacific island faunas. Robert Cowie, an authority on the island snails, attributed the decline in native species to a number of causes, all due in some way to man’s activities; first, over-enthusiastic collecting of the animals for their shells, and second, habitat destruction.14 Replacement of native forest with new introduced species of plants, for example, often created a habitat less well suited to the needs of indigenous snails. There was, however, another reason for the decline of native species, and that was man’s deliberate introduction of a predatory land snail, Euglandina rosea, to control another non-native land snail, Achatina fulica, a pest of banana crops. Originally Achatina had been introduced as a source of food in the 1960s but some of the snails had escaped. Euglandina, instead of preying on Achatina, turned its attention to the indigenous tree snails of the family Partulidae. These snails proved much the more appetizing. This caused a dramatic decline in the population of partulid snails with relatively little impact on Achatina. The whole experiment had backfired, and all because man had meddled where he should have known better. Partulid snails have since become the flagship species for conservation of island populations in the Pacific and the story of man’s well-meaning but clumsy interference with nature, a lesson in the relationship between man and native species.
If land snails from the Pacific were collected in their thousands during the nineteenth century, the sea snail known as the cowrie received even greater attention, then and previously. Nowhere has the influence of a snail shell been greater. While the scallop shell has a long pedigree as far as man is concerned as a symbol in ancient times, as the badge of St James and as a cradle for Venus, the shell of the cowrie achieved world-wide recognition. Its distinctive round shape – instead of being spirally wound it has a large body whorl which envelops the other whorls – and its smooth, glossy surface gave it the name ‘porcelain’ or ‘little pig’. The word derives from Hindi and Urdu kauri and has a Sanskrit origin. The Latin name Cypraea derives from the island of Cyprus where Aphrodite was worshipped as a goddess of fertility. Cowries were used particularly amongst the South Sea Islanders for personal adornment, but the cult of the cowrie extended far beyond the Pacific. Mary Saul, an author and collector of tropical shells, had this to say about the cowrie and our relationship with it:
The Giant African Land Snail, Achatina fulica, reaches eight inches in size; it has proved to be a highly invasive snail worldwide. |
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A snail shell with teeth. The smooth durable shell of the money cowrie (Cypraea moneta) combined with its small size makes it ideal currency. |
The cowrie was believed to have the power of conferring fertility, to be a protection against sterility and to increase sexual potency. It was the repository of the vital principle or ‘soul substance’, the ensurer of life and resurrection, which is life’s continuance. It became the symbol of womanhood, the source of life, dwelling place of the deity who made fertile both the woman and the crops and the murmur of whose voice could be heard in the shell. Such shells have been found among the most prized possessions of primitive peoples all over the world. No other objects have been so widely revered.15
In this floor mosaic from Piazza Armerina, Sicily, a lady holds a conch in her right hand. |
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Two cowrie shells, Cypraea moneta and Cypraea annulus, found widespread use as currency. Their small size, durability and relative abundance over a wide area of the Pacific and Indian oceans made them particularly well suited as a medium of exchange. Because they proved impossible to counterfeit, King Gezo of Dahomey reputedly told the explorer Richard Burton that he preferred them to gold.16 Cowrie currency was used in countries as far apart as China (where they were in circulation as money as early as the seventh century bc), Africa and India, even after metal coins were introduced. Indeed, the further from the source of the shells, the more the cowrie’s value increased. These snail shells were exchanged for gold, ivory and even land, as is shown in this extract from the narrative of an expedition to the river Niger in 1841:
For the purchase of this territory, we agreed to give seven hundred thousand cowries. In the presence of the sons and some of the headmen of the chief of the mountain villages of Lucojah, fourteen bags of cowrie shells were delivered for the Attah of Eggarah as the first instalment. We had been supplied with an even large quantity, bought in London by the ton, from the price of which we estimated the value of one thousand to be about fifteen pence. So large a treasure, amounting to about nine pounds in our money, is seldom known to change hands at one transaction between merchants in this country and many were the eyes that gloated upon it. Power was reserved to her Majesty the Queen of Great Britain to assume sovereignty of the aforesaid territory at her pleasure.17
It was their use in the slave trade, however, that earned them the epithet ‘despicable currency’. Cowries were shipped by the barrel-load to West Africa, arriving there by a circuitous route. The Maldives in the Indian Ocean were the commonest source of those cowries entering world trade. Shipped originally by Arab merchants who took them to North Africa for export across the Sahara and later by European traders who carried them to Lisbon, Amsterdam and London as ballast in their ships, they eventually arrived at the west coast of Africa to be exchanged for slaves.18
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A Ghanaian cedi coin showing a cowrie shell. Cedi is a Ghanaian word for cowrie, the original currency in that country and brought there in the fourth century through trade with Arabia. |
The conch, blown at the start of ceremonial events, can be heard as far as two miles away. This one comes from Hawaii. |
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Some of the magical powers of the cowrie transferred to another much larger sea shell, the conch. Those of us who are familiar with William Golding’s Lord of the Flies will know of its importance in the book. In this tale about children shipwrecked on a desert island, a conch shell was used to summon the boys to meetings. Holding the shell gave a boy the right to speak. As a symbol of democratic power its influence declined once cracks developed in the civilized behaviour of the group and when a boy was eventually killed, the conch too was destroyed.
This shell has played a recurring role in ceremonial and religious rituals throughout the world. The Hawaiian pu and the Korean na are both conch trumpets with mouth holes cut into the apex of the shell, while ‘Triton’s trumpet’, used throughout the Pacific and Indian oceans, is a conch with a hole cut into the side of the body whorl. Vishnu’s conch is a symbol of Dharma in the sense of divine order. Held in his inner, left hand, it is blown at the start of religious events and its sound heralded the great battle of Kurukshatra in the Mahabharata. In Tibet the conch makes an appearance as the dung-kar or white conch. Usually one note is produced from its sonorous chamber, though the pitch of the note is capable of being modified by inserting a hand into the conch’s aperture. Incidentally, the shape of the conch is special in two ways. First, its spire is symbolic of the path of death and rebirth. Second, its triangular shape and deep opening have a feminine connotation. In the iconography of Central America the conch is a symbol of life and wind. In the creation myth the god Quetzalcoatl creates life with the aid of a conch.
As far as the collectors of the shells of marine snails were concerned the appeal of the cones came second only to cowries. A tomb in Uruk in the Tigris-Euphrates valley yielded a 5,000-year-old necklace made from cone shells while Conus gloriamaris, the so-called Glory of the Sea, proved to be one of the most prized of all sea shells in the eighteenth and nineteenth centuries. Cones, mitre shells, volutes and many more kinds of shells found their way into the hearts of men and women because of the sheer aesthetic satisfaction they gave; as Robert Louis Stevenson speculated: ‘It is perhaps a far more fortunate destiny to have a taste for collecting shells than to be born a millionaire.’19
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The textile cone (Conus textile) is amongst the most venomous of this family of sea snails. Sometimes found buried in the sand, it can inflict a fatal sting to humans who unwittingly pick it up. |
MAN AND BODY
If the shell of the snail was perceived historically as its most attractive feature, the body of the snail appears to have had the opposite effect on man. Hidden from view, soft, extensile and often covered in a film of mucus, there seemed little reason to examine it and it is small wonder that the snail’s body was ignored, except as a source of sustenance.
The demonstration of the complex anatomy of the snail’s body was left to those of a scientific bent, and one of the first to produce anatomical drawings based on snail dissection was Jan Swammerdam, a seventeenth-century Dutch naturalist. He pioneered the use of the microscope and what he discovered both fascinated him and convinced him of the ingenuity of God’s handiwork. Of ‘the miraculous, viviparous, crystalline snail’ (Viviparus viviparus) he had this to say:
In this early (1730s) dissection of the viviparous snail by Jan Swammerdam, the young snail is seen within the adult body. |
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On the twelfth of March I began my observations upon this snail and collected a great number of the kind, which I put into a large basin filled with rain-water, and fed for a long time with potter’s earth, dissolved in the water about them. On the thirteenth of the same month I opened one of these snails, when I found nine living snails in its womb: the largest of these were placed foremost, as the first candidates for exclusion. I put them into fresh-water, and they lived till the eighteenth of the same month, moving and swimming, like snails full grown; nay, their manner of swimming was much more beautiful.20
What Swammerdam had demonstrated was ‘viviparity’, a phenomenon where the young of an animal are retained by the parent until fully developed. Edward Ruestow, in his book about the early Dutch microscopists, points out that despite the undoubted thrill Swammerdam experienced in uncovering such a phenomenon, to him it was a reminder of man’s ignorance and impotence. It left Swammerdam both with a sense of awe and ‘deep spiritual peril’.21 His contemporary, Antoni van Leeuwenhoek, was less disturbed by what he saw, but equally fascinated. Leeuwenhoek, however, was more concerned with improving the microscope’s ability to look at smaller and smaller animals than with pursuing a particular interest in snail anatomy. That was left to the English anatomist Martin Lister, whose microscopical studies of the internal organs of snails revealed a level of organization not previously appreciated.
Lister’s interest in snails led him to produce Historia sive synopsis methodica conchyliorum, a major work published in several parts and containing copper engravings done by his two daughters. Some were issued under the title De cochleis towards the end of the seventeenth century. There was little accompanying text, but his proved to be the first illustrated guide to snails produced in Great Britain and made the public aware of the diversity of these animals.
The soft body of the snail was disposed of by the shell collectors of the seventeenth and early eighteenth centuries, who classified their finds according to the hard, enduring shell. Today the classification of land snails is based as much on internal anatomy, particularly the reproductive system, as on shell characteristics. It wasn’t until the late eighteenth/early nineteenth century that the body of the snail received attention for its own sake. Thomas Say (1787–1834), an American naturalist, was one of the first to stress the importance of the animal within: ‘The animals that inhabit shells should guide us in our researches; they alone are the fabricators of the shell, and the shell is only their habitation to which they give the form, the bulk, hardness, colours and all the peculiarities of elegance we admire.’22
Philip Pearsall Carpenter (1819–1877), a conchologist from Warrington, made a telling observation of man’s relationship with the snail’s body in a lecture given to the Smithsonian Institution in 1861:
It is only in late years that enquiries have even attempted to gain information about the animals of shells. The very beauty of the shell has contributed to this result. Every sailor could collect shells and every lady could lay them on cotton in a drawer: the animal was a nuisance, liable to rot if not carefully extracted, only to be preserved in bottles of spirit, and then presenting nothing but a shrivelled or shapeless mass, fit only for the dissector’s knife.23
In one important respect, however, the bodies of land snails and slugs have always received man’s attention: as potential remedies for human ills. Pliny the Elder recommended they be taken for cough and stomach ache. He urged that they be swallowed in ‘uneven numbers’ so as to have the maximal beneficial effect. For dysentery, he chose African slugs, roasted and beaten to a powder with acacia and swallowed down with myrtle wine. For headaches, he suggested a head poultice made of slugs, but only with their heads chopped off. Toothache arising from an exposed cavity was said to be cured by introducing ‘the small grits of sand found in the horns of snails’.24 In Horace’s time African land snails were used as stimulants for the appetite, but it wasn’t until the seventeenth century that much more was heard about the medicinal properties of snails. Sir Kenelm Digby, seeing his wife fading away as a result of consumption, imported specimens of the Roman snail, Helix pomatia, from France in a desperate bid to save her life. Whether they proved successful isn’t recorded, but certainly his country estate at Gayhurst by the end of the twentieth century boasted a thriving population of Roman snails, probably the descendants of those early settlers.25
M. S. Lovell quotes a recipe for consumptives in which twenty-four garden snails and two sheep’s trotters are combined with half an ounce of comfrey root, a quart of spring water and a quart of milk, boiled so as to reduce the stock by half and then consumed twice a day. The same author quotes the example of a celebrated French tenor with a weak chest who every morning would crush a few live snails with a stone, pick off the pieces of broken shell, roll them in sugar and swallow them whole. As Lovell says, ‘the remedy was evidently efficacious as twenty years later M. Laborde still held a position as tenor and sang at the theatre at Brussels and at the opera in Paris’.26
Charles Pettitt, writing for the Conchological Society’s newsletter, points out that while snails were regarded as being particularly useful in lung complaints, by the seventeenth century they were also used to ‘ripen tumours, imposthumes and carbuncles’ and were considered a good remedy for gout.27 A mixture of pounded snails and crushed parsley, used as a poultice, was also believed to cure ‘scrofulous swellings’, while a local application of snails was thought to be beneficial in cases of stubborn eczema. Such was the faith in the snail’s healing power that in some quarters a live specimen was carried around the neck in a bag, then thrown on a fire in an attempt to transfer the ‘ague’ from an affected human onto the sacrificed snail. To be rid of warts, all that was necessary was to prick a snail as many times as there were warts and then impale the creature on a blackthorn bush. Warts, along with snail, withered magically to nothing!
The magical curative properties of snails remained in the public imagination well into the nineteenth century. Midway through the century you had only to take a walk through Covent Garden market to see two common snails, Helix pomatia and Helix aspersa, being sold in large numbers for medicinal purposes. Either the soft flesh was eaten whole or made into a mucilaginous broth, or the shell of the animal was pricked to enable the patient to suck out the ‘oozing liquor’. Such curative properties that they had were, I fear, largely in the mind. Fit only for the apothecary’s shelf or, in the case of snails found on the coast, enjoyed as a cheap meal, the snail’s body remained the province of the apothecary and the seafood merchant. Only later was the importance of land snails in the transmission of certain tapeworm and nematode worm infections recognized and the significance of freshwater snails as intermediate hosts for bilharzia appreciated.
The snail as a source of chemical compounds useful to man has an even longer and a much more noble history. Knowledge that the bodies of certain marine snails were capable of producing chemicals of use in dyeing cloth goes back to Classical times. Large numbers of the snail genus Murex were harvested as a source of a dye known as Tyrian purple. Legend has it that this property was first discovered when Hercules’ dog bit into a Murex on the shores of Tyre, an act that left the dog’s mouth stained with purple. The secretion from this snail’s hypobranchial gland is, in fact, a yellowish clear fluid which, in the presence of ultraviolet light, becomes purple on a cloudy day and sky blue on a cloudless day. The purple colour is remarkably stable, resisting most solvents, so making it an ideal dye. Pliny the Elder described the process by which the dye was extracted back in the first century ad.28 Twelve thousand Murex shells were needed to produce just 1.5 gm of purple dye, enough for a single toga. The three snail species used were Murex trunculus, Murex brandaris and Purpura haemastoma, all of which existed in abundance on the shores of the eastern Mediterranean. The manufacture of Tyrian purple led directly to the growth of Tyre, then capital of ancient Phoenicia, which prospered in consequence as a trading and commercial centre. Today in Lebanon mounds of broken Murex shells can still be found at the sites of ancient dye works. ‘Wearing purple’ became the prerogative of emperors, senators and priests while the term ‘born to the purple’, a concept that derives from the Roman Imperial and Byzantine concept of ‘porphyrogenitos’, acquired the connotation of a royal birth. Throughout antiquity purple was regarded as one of the most precious and beautiful of colours and it was not until the middle of the fifteenth century and the end of the Middle Ages that its supremacy waned.
Another product of the snail’s body has come in for more recent attention. It has long been known that the majority of marine snails are predatory animals and cones in particular use venom to paralyse their prey and to defend themselves against other predators. The cones offer examples of sophisticated systems for delivering toxins. Conus magus, a fish eater, detects its prey using chemical sensors. When these are activated, a proboscis is extended and if contact is made with a fish, a single tooth, shaped like a harpoon and hollowed inside, is released. Through the tooth is injected venom and, once paralysed, the prey is swallowed whole. Conus geographicus possesses a sting fatal to man. There is no antidote to its poison. The venom proved complex to analyse and was found to contain several active pharmacological agents or ‘conopeptides’, each with its own mode of action but functioning together as a coordinated ‘cabal’.29 It has been shown that as well as having harmful properties, some of the venom components have therapeutic potential as far as man is concerned. Several have reached the stage of human clinical trials as therapeutic agents for relieving pain. While combination drug therapy is as yet little used in medicine, experience of the chemical constituents of cone venoms successfully working together suggests that more drug combinations could be tried in some of the more intractable conditions that affect man.
Murex brandaris, a sea snail commonly used for the extraction of Tyrian purple, from G. B. Sowerby’s 1848 Thesaurus Conchyliorum. |
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MAN AND CREATURE
The artificial distinction I have drawn between body and shell reflects, I believe, a fragmented attitude towards the snail. Interest in the creature was driven mainly by what it could provide us with. Our relationship over the years has been largely one of exploitation. As we have seen, the shells of many species were seen as collectable objects; one, the cowrie, provided us with useful coinage, while another, the conch, provided us with a ceremonial instrument. Likewise, the bodies of certain snails provided us both with food and medicine and, on occasions, useful chemicals. A relationship with the snail that took account of how the creature behaved or interacted with its surroundings took much longer to develop. The literature reflecting this new way of viewing the snail came out piecemeal, written in language designed for the specialist and often hidden away in journals that were difficult to access. There were of course passing references to snails amongst the writings of different authors who found qualities in the animal that reflected aspects of human behaviour, but no substantial book. Like the marginal illustrations in medieval manuscripts, where the snail’s image unexpectedly popped up from the page, the snail found itself, almost by accident, introduced into literature for its metaphorical qualities or as a creature onto which man could project his feelings. It is those attributes of a snail that were given it by man, its quintessential properties, that I want to examine next.