holy water stoup (Saint-Sulpice church, Paris)
scallop (Saint-Pierre collegiate church, French Riviera)
The oldest consumption of shellfish by Homo sapiens dates back to around 160,000 years ago and they were an important source of food for coastal populations.
Marine pollution encourages us to be vigilant about the origin of seafood. In fact, most seashells are filter feeders which excrete part of the non-degradable toxins in their waste and in their shells. Four types of contaminants accumulate in shellfish
NB mussels and oysters detoxify from lead by storing it in their shells.
It will be noted that it is mainly bivalves that are consumed although half as numerous as gastropods :
The oyster Lunch
Jean-François TROY(1679-1752)
With the sedentarization of prehistoric men, at the beginning of the Neolithic, the first forms of society appeared and the only way to acquire a good (tools, animals, food, ...) was to exchange it for a service or another item (barter principle).
But barter limits the development of trade because supply does not necessarily correspond exactly to demand and perishable goods are only available at certain times of the year (harvests for food for example).
Thus the emergence of exchange units : seashells in the beginning then precious metals (silver, gold).
The shells had the advantage of bringing together the main characteristics of a currency :
It is especially the porcelains, in particular the two species below, which were used as money and which are more generally called cowries.
They are found at the museum of the "national bank of Belgium" and on the pediment of the building of the "Central Bank of the States of West Africa" in Bamako, Mali.
Monetaria moneta
Monetaria annulus
The shells were used to make various tools (scrapers, projectile's points, vase, hook, etc.).
In the Marquesas Islands, some varieties of murex or cowries were cleverly modified to serve as peelers for the breadfruit.
In classical times, in Athens, citizens who endangered democracy (because of their power) were banished for ten years. The vote for the judgment was written on oyster shells, hence the term ostracism (from the Greek ostrakon, oyster).
The filaments of mussels (byssus) were called "marine silk" and were used to make or embroider clothes.
conch primitive horn
sharply carved columella
Not to mention pearl oysters, this is the area that best contributes to the popularity of seashells.
Mother-of-pearl (the inner layer of the shell) was an element of choice in jewelry and marquetry.
haliotid frieze
shell wreath
The natural beauty of seashells has often been used in decoration. The frieze of abalone comes from the rock cave of the Chateau d'Urfé
Cameos, these small, slightly raised engravings were cut from agate. The beginning of travels around the world, in the XVIIth century, allowed the discovery of new shells which present a natural gradient in the thickness of the shell.
cowry necklace
cameo (Cassis madagascariensis)
In ancient times, the color purple, the prerogative of the Roman emperors, was much sought after. The oldest traces have been found in Crete and date back to 1600 BC.
These dyes come in particular from "Bolinus brandaris" or "Stramonita haemastoma"
Bolinus brandaris
Stramonita haemastoma
We can notice the influence of shells on the architecture of some traditional constructions
Tây Phuong pagoda
asian sea seashells
The keep of the Château de Chambord has a staircase in its center made up of two superimposed helices and ends with a single helix staircase inspired by the columella of seashells.
The roof of the Sydney Opera House represents superimposed seashells.
Lunulicardia retusa auricula
Some seashells conceal true mathematical objects :
Cymbiola innexa & Oliva porphyra
Sierpinski fractal triangles
nautilus
logarithmic spiral
The analysis of shell remains provides valuable insights into the study of archaeological sites, understanding the paleoclimate and the trade economy of prehistoric societies
In medicine, the amazing properties of toxins from certain poisonous shells (Conidae) led to analgesic treatments and are being studied for epilepsies or the recovery of damaged nerves.
The "Conus magus" cone venom has made it possible to synthesize an analgesic for severe chronic pain, 2000 times more powerful than morphine with the advantage of not causing addiction (Prialt®).
The cone venom "Conus victoriae" allowed the synthesis of a drug used in the treatment of neuropathic pain 100 times more active than last generation antiepileptics (ACV1 ɑ-conotoxin : C71H103N23O25S4).
The venom (µ-conotoxin) of certain Conidae (Conus marmoreus, geographus, striolatus, ...) contains peptides (which we do not know how to synthesize) which allow to close / open the sodium channels (propagation of the nervous signal) and therefore to study the functioning of the nervous system and to produce new insecticides, local analgesics, antiarrhythmics, anti-epileptics, etc.
Mother-of-pearl powder was the natural anti-wrinkle cream of Chinese empresses and the foundation of Japanese geishas. It is currently marketed as dietary supplements and cosmetic creams.
The nacre of the largest pearl oyster species (Pinctada maxima) contains almost all the proteins, amino acids, minerals, and trace elements involved in cellular metabolism and necessary for the body's proper functioning. It has been the subject of studies (CNRS : CE18 - biomedical innovation) highlighting its involvement in the healing processes of bones, cartilage, ligaments, muscles, tendons, and the dermis. New therapeutic applications are currently being developed (endosteal implants) and for certain pathologies (osteoporosis, osteoarthritis).
The force of gravity exerted by the Earth slows down the rotation of the Moon around the Earth. Currently, the Moon circles the Earth in 29.5 days (1 month, by definition). It has been calculated that the Earth-Moon distance increases by 3.5 cm / year which induces an extension of the rotation period. The nautilus is living proof of this slowdown: the nautilus shell is divided into a series of compartments by transverse partitions. The nautilus adds a new layer every day, marked with a new streak. At each full moon it has therefore secreted 30 streaks, it then leaves the compartment it occupied and moves into a new one that it separates from the previous one by a partition (This phenomenon is linked to the spawning instinct of the nautilus, which brought up close to the surface on each full moon). The study of fossils shows that the number of striations between two partitions decreases as the age of the fossils increases. Instead of the 30 striations of the current nautilus, there are only 9 of the fossils dating back 420 millions years. This is an indirect confirmation that at that time, a lunar month only lasted 9 days.
Surprising properties have been discovered in molluscs, promising sources of technological innovation :
The shell, made up of 95% calcium carbonate, has the property of trapping heavy metals present in the water. It would therefore be possible to design water purifiers based on shell powder.
The shell of abalones (Haliotidae) are twice as hard as the best high-tech ceramics. The pearly coating is a perfect tiling which combines rigid layers of calcium carbonate (aragonite) and flexible layers of proteins (Lustrin-A) which gives it a flexibility capable of absorbing violent shocks and supporting weights of several tonnes. Scientists are inspired to design new materials that will be revolutions comparable to the advent of the Iron Age or the Industrial Revolution.
The byssus of mussels (Mytilidae) which allows them to attach to rocks is, in fact, the most powerful glue in the world: it resists UV, salt, high and low temperatures, it is very resistant and especially glue under water. These filaments also make it possible to produce the best suture threads used in particular in cosmetic surgery.
