المركبات الكيميائية - تراث الطبيب السومري .. من کیمیائی ما قبل التاريخ

Chemical Compounds - The Sumerian Physician's Legacy.. From Prehistoric Chemist to Chemical Philosopher

Chemical Compounds

Ancient chemists had a reasonable stock of chemical compounds that they could use in various processes, in addition to pure metals and their alloys. As with therapeutic materials, these chemical compounds have not reached us in the pristine state they were in ancient times, so we have to guess their uses from the artifacts discovered in excavations such as pestles, mortars, mills, refineries, distillation units and crucibles. One of the Mesopotamian discoveries was a pottery vessel in the form of a double-rimmed pot, which was probably used to extract vegetable oils or aromatic extracts. The raw material was placed between the two rims, the pot was covered with a lid, and a solvent (water or oil) was boiled at the bottom. The vapor of the boiling solvent condensed on the lid and ran over the raw material, extracting the desired ingredient and then dripping back to the bottom of the pot—the same principle used today to filter coffee by extraction (11).

We now have an idea of ​​some other common compounds, because one fine day in the third millennium in Mesopotamia, an anonymous Sumerian physician took a clay tablet six inches long and four inches wide, and inscribed on it a list of his favorite recipes.

The Sumerian Physician's Legacy

Some of the ingredients in the recipes were salts whose names were repeated many times in our story: sodium chloride (known as table salt - found in the form of natural deposits or obtained by evaporating sea water), sodium carbonate (later known as soda ash by Europeans and found in natural deposits or produced by burning plants rich in sodium), and ammonium chloride, later known as ammonium salt by Europeans and obtained by burning large blocks of coal or heating camel dung that had been exposed to the atmosphere for a long time). As for minerals such as alum or aluminum and potassium sulphate, and gypsum or calcium sulphate, they were collected and ground for medicine, and gypsum was also used as a type of mortar (12).

Sodium nitrate or potassium nitrate also appear in these recipes, both of which were later called Peter's salt or nitre by Europeans (and nitre was attributed with many therapeutic properties throughout the ages, and was prescribed for conditions as diverse as impotence, asthma, and sexual arousal - but most of these treatments proved ineffective.

However, nitre rose in value greatly when it was found to be an essential component of gunpowder. The colorless crystalline compounds that make up nitre are produced by the action of bacteria on nitrogenous wastes such as urine and manure. These compounds are familiar to anyone who has come into contact with stables. From our later experience, the Sumerians may have collected nitre from the sides of sewers and animal farms, and it undoubtedly contained many impurities. Of course, it was not a compound as clean and crystalline as the ones found on pharmacy shelves today. They were often dirty mixtures, and even one of the most famous chemical compounds, water, was often a dark, cloudy, brownish substance.

Recipes included other ingredients from animals (milk, snake skin, tortoise shell) and plants (myrtle, thyme, willow, pear, fig, and date). These ingredients were used directly or in powdered form. Sometimes recipes called for the desired ingredient to be extracted with boiling water, but if the ingredient was insoluble in water, it could be extracted with beer or wine. Wine or beer, of course, contained ethanol—a chemical that was just as important today. Ethanol is produced when certain single-celled algae called yeast consume sugar in a process called fermentation. The yeasts that cause fermentation are found naturally on vines, so fermentation can occur spontaneously in sugar-rich grape juice. The conditions that encourage fermentation and ethanol production have been known and used for probably the past ten thousand years, making fermentation one of the oldest, if not the most famous, chemical processes. Ethanol is an excellent solvent for extracting carbon-containing organic materials such as vegetable oils and alcohol. The organic end of the ethanol molecule, which contains carbon and hydrogen, mixes well with plant materials, which are also organic. The alcoholic end of ethanol, which consists of oxygen and hydrogen, mixes well with water, which also contains oxygen and hydrogen in the familiar ratio of H2O. The organic materials mixed with ethanol can be converted into an aqueous solution, and these extracts can then be preserved and stored in solid, liquid, or powder form, as is the case today.

The Sumerian physician also used vegetable oils and animal fats as extracts and ointments, but unfortunately we do not have information about the medicinal value of the medicinal herbs and for which diseases they were used, perhaps because the physician was restricted by the limited space of the tablet or because of the cumbersome and slow nature of cuneiform writing. However, some of the therapeutic effects can be guessed. For example, in the twelfth recipe the physician advises:

Sieve and knead together - all together - the shell of the turtle and the first-sprouting sodium-containing naga plant, salt, and mustard. Wash the diseased spot with good beer or hot water. Rub the diseased spot with all of this. After rubbing, anoint with vegetable oil and cover with fir powder (13).

The washing prescribed in this treatment cleans the affected area, while the salt and alcohol undoubtedly act as disinfectants or antiseptics. Two of the bar's recipes call for the use of an alkali salt, sodium or potassium, with natural fat - which produces soap - and this again helps to clean the wound or affected area if used externally.

It is interesting that our Sumerian physician did not record any magical ritual incantations to be used with medicine, which indicates that rituals were either not used or were not considered important enough to occupy a place on the specified tablet. However, magicians later became more important than doctors in treating diseases in Babylonian society, which produced one of the most prolific lists of medicines (14). In fact, illness was considered possession or demonic possession caused by committing vice, and drugs were used to expel evil spirits rather than to purify the patient. The medicine was deliberately made disgusting in order to expel the devil (and the poor patient had no choice but to submit), so the treatment consisted of raw meat, the body of a snake, tree bark, oil, rotten food, crushed bones, fat, filth, and human or animal feces. We have mentioned this here because the theory of demonic possession resurfaced in Europe in the 1600s AD. The need for such drastic medical procedures can be understood if we consider the quality of life in those ancient civilizations. People routinely died from tooth decay, minor cuts, infections, and fevers that could be treated within an hour with the medicines available today. They suffered from anorexia and blindness. Pain and parasites were accepted constants of life. Women had about the same chance of surviving childbirth as they would have had to go to war, which was often the case, and children had no greater chance of surviving childhood.

Means of escape from life were often as important as means of preserving it, and one of these was through art. Although the word art here suggests painted objects and walls, there was a familiar medium used to convey the idea of ​​personal beautification. The story of Joseph in the Bible is a case in point. In this story, Joseph’s brothers throw him into a well and leave him to die. His crime? They were jealous of his colorful robe.

Paint and dye

Clothes were made of wool, cotton, and linen, but wool was the most common, and dyes were generally organic, the name given to a class of compounds consisting of carbon and hydrogen, or hydrocarbons, which were extracted at that time from animals and plants.

Inorganic is the name given to compounds that are not hydrocarbons, which are extracted from minerals. A group of inorganic salts are used as dye fixatives, substances that fix the dye by chemically bonding the dye to the protein structure of the clothing. Indigo, extracted from the indigo plant, was the preferred blue dye, and we will see how this dye would remake chemical and social history again with the beginning of the 1900s of the present era). The dye after fermentation in the rag (a large vessel) was colorless. However, clothes dipped in it and then exposed to air would turn dark blue in a few seconds. Other plants were used for dyeing, such as saffron, which produces a yellow dye, and madder, which produces a red dye, found on the clothes of Egyptian mummies. In Mesopotamia, the red dye came from cochineal, which is the powder of a scale insect called cochineal (plant louse) that lives on oak trees in the Mediterranean region. The most expensive dye was purple, which was obtained from a gland in a mussel (a mollusk found only in special locations on the Mediterranean coast.

Each of these creatures gives only a small amount of an oily liquid with a garlic smell. Some record that 12,000 mussels are needed to obtain a sample the size of one drop of dye (15), but when used, it gives an unusual and captivating purple dye.

In addition to clothing and its decorations, cosmetics were used to improve personal appearance, such as perfumes. One Babylonian text in particular indicates that women worked In the preparation of perfumes like men, women have at least contributed to this industry of chemical technology and most likely they have contributed in other fields. Over time these chemical techniques have developed until craftsmen can produce many interesting and useful materials. Glass was one of the most interesting of these materials and it resembled gold at first as it had no purpose other than beauty.

Glass

Silicon makes up about twenty-five percent of the Earth's crust, second only to oxygen in prevalence. Most of the earth we stand on is silicon-oxygen silicate, or what is commonly known as sand. Glass, made from molten silicates, was produced naturally by lightning strikes, volcanoes, or in places where meteorites have carved into the Earth's surface. Egyptians have used glass for glazing since Neolithic times, but glass production as a separate material for purpose did not occur until 3000-2000 BC in Mesopotamia.

Originally, craftsmen made glass from sand or quartz (silicon dioxide) and raw sodium carbonate, which in Egypt was found in layers beneath the lakes near Alexandria. Without sodium carbonate, a high-temperature flame of 1700 °C was required to melt the sand. Adding sodium carbonate lowers the melting point because it produces a molten sodium oxide. Glass made with sodium dissolves to some extent in water, which is often used in art. However, glass vessels were produced for the privileged few) to store ointments or other materials that were absorbed by ceramic pots (16). Around 1300 BC, craftsmen found that the introduction of calcium oxide, another chemical compound known to the ancients, reduced the solubility of glass. Later Europeans called it quicklime or quicklime (unslaked lime or lime), which was formed by heating calcium carbonate found in shells or by heating natural deposits of limestone or chalk.

As soon as this technique was discovered, glass factories began immediately in ancient Egypt. In these ancient civilizations, glass was cast and not blown. It was a cloudy blue (coloured by copper compounds and sometimes cobalt), with some other colours acquired by the glass. The Assyrians used tin oxide and lead antimony to colour their ornamental glass white and yellow respectively. It was believed that the Assyrians knew how to make aqua regia (a mixture of nitric and hydrochloric acids), because they used gold salts to give their glass a red colour, and aqua regia was necessary to dissolve the gold.

Other Materials and Methods

While the above techniques constitute an impressive list, they are not exhaustive of the achievements of antiquity. We have not delved into the expertise of the Hindus in tanning hides or the art of metal casting in Central America. Another technique that we will discuss here, more because of its mystique than because of its high degree of technical expertise, is the famous Egyptian art of mummification.

To make a mummy, the Egyptians would eviscerate the body and stuff it with wine and perfume. They would extract the brain piece by piece from the nostril using an iron hook (this is perhaps the most mysterious part of the process). They would then soak the body in a bath of natron (a salt of sodium, aluminum, silicon, and oxygen) for 70 days. This process kills the bacteria that cause decomposition and strips the cells of water, so that in the future bacteria would not be able to find a suitable home. The body was then wrapped in strips of cloth coated with gum and placed in a sealed grave, isolated from the spoiling moisture and air, a process no more mysterious than that of salting meat.

With the development of mummification, glass, and dyeing, societies became successful enough to devote time and materials to tasks not directly related to the daily labor of survival. This trend culminated in a profession that required no manual labor and produced no product other than the thought of philosophy. Civilization and chemistry gave philosophers time to think and a subject to think about.

From about 2000 to 300 BC: The Philosophers

While chemical facts were continually being accumulated by craftsmen, they were also studied by philosophers—who also worked as mathematicians, astronomers, anatomists, physicists, theologians, and political theorists. In fact, it was not until the early nineteenth century that European scientists began to think of their work as separate from philosophy. Although philosophy was prevalent in all cultures, the philosophers of Greece were the most influential in the development of modern chemistry. These thinkers derived hypotheses about the nature of matter and the interactions between substances that helped or hindered chemical developments over the next two thousand years.