Alchemy was an ancient branch of natural philosophy, a philosophical and protoscientific tradition practiced throughout Europe and Asia, originating in Greco-Roman Egypt in the first few centuries AD. It aims to purify and perfect certain objects. Common aims were chrysopoeia, the transmutation of "base metals" into "noble metals"; the perfection of the human body and soul was thought to permit or result from the alchemical magnum opus and, in the Hellenistic and Western mystery tradition, the achievement of gnosis. In Europe, the creation of a philosopher's stone was variously connected with all of these projects. In English, the term is limited to descriptions of European alchemy, but similar practices existed in the Far East, the Indian subcontinent, the Muslim world. In Europe, following the 12th-century Renaissance produced by the translation of Medieval Islamic works on science and the rediscovery of Aristotelian philosophy, alchemists played a significant role in early modern science.
Islamic and European alchemists developed a structure of basic laboratory techniques, theory and experimental method, some of which are still in use today. However, they continued antiquity's belief in four elements and guarded their work in secrecy including cyphers and cryptic symbolism, their work was guided by Hermetic principles related to magic and religion. Modern discussions of alchemy are split into an examination of its exoteric practical applications and its esoteric spiritual aspects, despite the arguments of scholars like Holmyard and von Franz that they should be understood as complementary; the former is pursued by historians of the physical sciences who examine the subject in terms of early chemistry and charlatanism, the philosophical and religious contexts in which these events occurred. The latter interests historians of esotericism and some philosophers and spiritualists; the subject has made an ongoing impact on literature and the arts. Despite this split, which von Franz believes has existed since the Western traditions' origin in a mix of Greek philosophy, mixed with Egyptian and Mesopotamian technology, numerous sources have stressed an integration of esoteric and exoteric approaches to alchemy as far back as Pseudo-Democritus's first-century AD On Physical and Mystical Matters.
Although alchemy is popularly associated with magic, historian Lawrence M. Principe writes: Most readers are aware of several common claims about alchemy—for example... that it is akin to magic, or that its practice or now is deceptive. These ideas about alchemy emerged after. While each of them might have limited validity within a narrow context, none of them is an accurate depiction of alchemy in general." The word alchemy comes from Old French alquemie, used in Medieval Latin as alchymia. This name was itself brought from the Arabic word al-kīmiyā' composed of two parts: the Late Greek term khēmeía, khēmía, meaning'to fuse or cast a metal', the Arabic definite article al-, meaning'The'. Together this association can be interpreted as'the process of transmutation by which to fuse or reunite with the divine or original form', its roots can be traced to the Egyptian name kēme, meaning'black earth' which refers to the fertile and auriferous soil of the Nile valley, as opposed to red desert sand.
According to the Egyptologist Wallis Budge, the Arabic word al-kīmiyaʾ means "the Egyptian ", borrowing from the Coptic word for "Egypt", kēme. This Coptic word derives from Demotic kmỉ, itself from ancient Egyptian kmt; the ancient Egyptian word referred to both the country and the colour "black". However, according to Mahn, this theory may be an example of folk etymology. Assuming an Egyptian origin, chemistry is defined as follows: Chemistry, from the ancient Egyptian word "khēmia" meaning transmutation of earth, is the science of matter at the atomic to molecular scale, dealing with collections of atoms, such as molecules and metals. Thus, according to Budge and others, chemistry derives from an Egyptian word khemein or khēmia, "preparation of black powder" derived from the name khem, Egypt. A decree of Diocletian, written about 300 AD in Greek, speaks against "the ancient writings of the Egyptians, which treat of the khēmia transmutation of gold and silver"; the Medieval Latin form was influenced by Greek chymeia meaning'mixture' and referring to pharmaceutical chemistry.
Alchemy is several philosophical traditions spanning three continents. These traditions' general penchant for cryptic and symbolic language makes it hard to trace their mutual influences and "genetic" relationships. One can distinguish at least three major strands, which appear to be independent, at least in their earlier stages: Chinese alchemy, centered in China and its zone of cultural influence. Chinese alchemy was connected to Ta
A homunculus is a representation of a small human being. Popularized in sixteenth-century alchemy and nineteenth-century fiction, it has referred to the creation of a miniature formed human; the concept has roots in preformationism as well as earlier folklore and alchemic traditions. The homunculus first appears by name in alchemical writings attributed to Paracelsus. De natura rerum outlines his method for creating homunculi: That the sperm of a man be putrefied by itself in a sealed cucurbit for forty days with the highest degree of putrefaction in a horse's womb, or at least so long that it comes to life and moves itself, stirs, observed. After this time, it will look somewhat like a man, but transparent, without a body. If, after this, it be fed wisely with the Arcanum of human blood, be nourished for up to forty weeks, be kept in the heat of the horse's womb, a living human child grows therefrom, with all its members like another child, born of a woman, but much smaller. Comparisons have been made with several similar concepts in the writings of earlier alchemists.
Although the actual word "homunculus" was never used, Carl Jung believed that the concept first appeared in the Visions of Zosimos, written in the third century AD. In the visions, Zosimos encounters a priest who changes into "the opposite of himself, into a mutilated anthroparion"; the Greek word "anthroparion" is similar to "homunculus" – a diminutive form of "person". Zosimos subsequently encounters other anthroparion in his dream but there is no mention of the creation of artificial life. In his commentary, Jung equates the homunculus with the Philosopher's Stone, the "inner person" in parallel with Christ. In Islamic alchemy, Takwin was a goal of certain Muslim alchemists, a notable one being Jābir ibn Hayyān. In the alchemical context, Takwin refers to the artificial creation of life in the laboratory, up to and including human life; the homunculus continued to appear in alchemical writings after Paracelsus' time. The Chymical Wedding of Christian Rosenkreutz for example, concludes with the creation of a male and female form identified as Homunculi duo.
The allegorical text suggests to the reader that the ultimate goal of alchemy is not chrysopoeia, but it is instead the artificial generation of humans. Here, the creation of homunculi symbolically represents spiritual regeneration and Christian soteriology. In 1775, Count Johann Ferdinand von Kufstein, together with Abbé Geloni, an Italian cleric, are reputed to have created ten homunculi with the ability to foresee the future, which von Kufstein kept in glass containers at his Masonic lodge in Vienna. Dr. Emil Besetzny's Masonic handbook, Die Sphinx, devoted an entire chapter to the wahrsagenden Geister; these are reputed to have been seen by several people, including local dignitaries. References to the homunculus do not appear prior to sixteenth-century alchemical writings; the mandragora, known in German as Alreona, Alraun or Alraune is one example. In Liber de imaginibus, Paracelsus however denies, he attacks dishonest people who carve roots to sell them as Alraun. He clarifies that the homunculus’ origins are in sperm, that it is falsely confused with these ideas from necromancy and natural philosophy.
The homunculus has been compared to the golem of Jewish folklore. Though the specifics outlining the creation of the golem and homunculus are different, the concepts both metaphorically relate man to the divine, in his construction of life in his own image. Preformationism is the popular theory that animals developed from miniature versions of themselves. Sperm were believed to contain complete preformed individuals called "animalcules". Development was therefore a matter of enlarging this into a formed being; the term homunculus was used in the discussion of conception and birth. Nicolas Hartsoeker postulated the existence of animalcules in the semen of other animals; this was the beginning of spermists' theory, who held the belief that the sperm was in fact a "little man", placed inside a woman for growth into a child. This seemed to them to neatly explain many of the mysteries of conception, it was pointed out that if the sperm was a homunculus, identical in all but size to an adult the homunculus may have sperm of its own.
This led to a reductio ad absurdum with a chain of homunculi "all the way down". This was not considered by spermists a fatal objection however, as it neatly explained how it was that "in Adam" all had sinned: the whole of humanity was contained in his loins; the spermists' theory failed to explain why children tend to resemble their mothers as well as their fathers, though some spermists believed that the growing homunculus assimilated maternal characteristics from the womb environment in which they grew. The homunculus is used today in scientific disciplines such as psychology as a teaching or memory tool to describe the distorted scale model of a human drawn or sculpted to reflect the relative space human body parts occupy on the somatosensory cortex and the motor cortex. Both the motor and sensory homunculi appear as small men superimposed over the top of precentral or postcentral gyri for motor and sensory cortices, respectively; the homunculus is oriented with feet medial and shoulders lateral on top of both the precentral and the postcentral gyrus.
The man's head is depicted upside down in relation to the rest of the body such that
Folklore is the expressive body of culture shared by a particular group of people. These include oral traditions such as tales and jokes, they include material culture, ranging from traditional building styles to handmade toys common to the group. Folklore includes customary lore, the forms and rituals of celebrations such as Christmas and weddings, folk dances and initiation rites; each one of these, either singly or in combination, is considered a folklore artifact. Just as essential as the form, folklore encompasses the transmission of these artifacts from one region to another or from one generation to the next. Folklore is not something one can gain in a formal school curriculum or study in the fine arts. Instead, these traditions are passed along informally from one individual to another either through verbal instruction or demonstration; the academic study of folklore is called Folklore studies, it can be explored at undergraduate, graduate and Ph. D. levels. To understand folklore, it is helpful to clarify its component parts: the terms folk and lore.
It is well-documented. He fabricated it to replace the contemporary terminology of "popular antiquities" or "popular literature"; the second half of the compound word, proves easier to define as its meaning has stayed stable over the last two centuries. Coming from Old English lār'instruction,' and with German and Dutch cognates, it is the knowledge and traditions of a particular group passed along by word of mouth; the concept of folk proves somewhat more elusive. When Thoms first created this term, folk applied only to rural poor and illiterate peasants. A more modern definition of folk is a social group which includes two or more persons with common traits, who express their shared identity through distinctive traditions. "Folk is a flexible concept which can refer to a nation as in American folklore or to a single family." This expanded social definition of folk supports a broader view of the material, i.e. the lore, considered to be folklore artifacts. These now include all "things people make with words, things they make with their hands, things they make with their actions".
Folklore is no longer circumscribed as being chronologically obsolete. The folklorist studies the traditional artifacts of a social group. Transmission is a vital part of the folklore process. Without communicating these beliefs and customs within the group over space and time, they would become cultural shards relegated to cultural archaeologists. For folklore is a verb; these folk artifacts continue to be passed along informally, as a rule anonymously and always in multiple variants. The folk group is not individualistic, it nurtures its lore in community. "As new groups emerge, new folklore is created… surfers, computer programmers". In direct contrast to high culture, where any single work of a named artist is protected by copyright law, folklore is a function of shared identity within the social group. Having identified folk artifacts, the professional folklorist strives to understand the significance of these beliefs and objects for the group. For these cultural units would not be passed along unless they had some continued relevance within the group.
That meaning can however morph. So Halloween of the 21st century is not the All Hallows' Eve of the Middle Ages, gives rise to its own set of urban legends independent of the historical celebration; the cleansing rituals of Orthodox Judaism were good public health in a land with little water. Compare this to brushing your teeth transmitted within a group, which remains a practical hygiene and health issue and does not rise to the level of a group-defining tradition. For tradition is remembered behavior. Once it loses its practical purpose, there is no reason for further transmission unless it has been imbued with meaning beyond the initial practicality of the action; this meaning is at the core of the study of folklore. With an theoretical sophistication of the social sciences, it has become evident that folklore is a occurring and necessary component of any social group, it is indeed all around us, it does not have to be antiquated. It continues to be created, transmitted and in any group is used to differentiate between "us" and "them".
Folklore began to distinguish itself as an autonomous discipline during the period of romantic nationalism in Europe. A particular figure in this development was Johann Gottfried von Herder, whose writings in the 1770s presented oral traditions as organic processes grounded in locale. After the German states were invaded by Napoleonic France, Herder's approach was adopted by many of his fellow Germans who systematized the recorded folk traditions and used them in their process of nation building; this process was enthusiastically embraced by smaller nations like Finland and Hungary, which were seeking political independence from their dominant neighbours. Folklore as a field of study further developed among 19th century European scholars who were contrasting tradition with the newly developing modernity, its focus was the oral folklore of the rural peasant populations, which were considered as residue and survivals of the past that continued to exist within the lower strata of society. The "Kinder- und Hausmärchen" of the Brothers Grimm is the best known but by no means only collection of verbal folklore of the European peasantry of th
The precentral gyrus is a prominent gyrus on the surface of the posterior frontal lobe of the brain. It is the site of the primary motor cortex that in humans is cytoarchitecturally defined as Brodmann area 4; the precentral gyrus lies in front of the postcentral gyrus - on the lateral side of each cerebral hemisphere - from which it is separated by the central sulcus. Its anterior border is represented by the precentral sulcus, while inferiorly it borders to the lateral sulcus. Medially, it is contiguous with the paracentral lobule; the internal pyramidal layer of the precentral cortex contains giant pyramidal neurons called Betz cells, which send long axons to the contralateral motor nuclei of the cranial nerves and to the lower motor neurons in the ventral horn of the spinal cord. These axons form the corticospinal tract; the Betz cells along with their long axons are referred to as upper motor neurons. There is a precise somatotopic representation of the different body parts in the primary motor cortex, with the leg area located medially, the head and face area located laterally on the convex side of the cerebral hemisphere.
The arm and hand motor area is the largest and occupies the part of precentral gyrus, located inbetween the leg and face area. As they travel down through the cerebral white matter, the motor axons move closer together and form part of the posterior limb of the internal capsule, they continue down into the brainstem, where some of them, after crossing over to the contralateral side, distribute to the cranial nerve motor nuclei.. After crossing over to the contralateral side in the medulla oblongata, the axons travel down the spinal cord as the lateral corticospinal tract. Fibers that do not cross over in the brainstem travel down the separate ventral corticospinal tract and most of them cross over to the contralateral side in the spinal cord, shortly before reaching the lower motor neurons. Branches of the middle cerebral artery provide most of the arterial blood supply for the primary motor cortex; the medial aspect is supplied by branches of the anterior cerebral artery. Lesions of the precentral gyrus result in paralysis of the contralateral side of the body - see upper motor neuron.
Corticospinal tract Motor cortex List of regions in the human brain
The postcentral gyrus is a prominent gyrus in the lateral parietal lobe of the human brain. It is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch. Like other sensory areas, there is a map of sensory space in this location, called the sensory homunculus; the primary somatosensory cortex was defined from surface stimulation studies of Wilder Penfield, parallel surface potential studies of Bard and Marshall. Although defined to be the same as Brodmann areas 3, 1 and 2, more recent work by Kaas has suggested that for homogeny with other sensory fields only area 3 should be referred to as "primary somatosensory cortex", as it receives the bulk of the thalamocortical projections from the sensory input fields; the lateral postcentral gyrus is bounded by: medial longitudinal fissure medially central sulcus rostrally postcentral sulcus caudally lateral sulcus inferiorly The postcentral gyrus includes Brodmann areas 1, 2, 3. Brodmann area 1 occupies the apex of the postcentral gyrus.
List of regions in the human brain ancil-1040 at NeuroNames - area 1 ancil-1041 at NeuroNames - area 2 ancil-1042 at NeuroNames - area 3
Wolfgang Grodd is a German radiologist and professor emeritus of the University of Tübingen. He is known for his scientific works on the development and application of structural and functional magnetic resonance imaging in metabolic diseases, sensorimotor representation, language production and cognitive processing and thalamus. Grodd is research scientist at the Max Planck Institute for Biological Cybernetics. After serving his military duty from 1960 to 1964, Grodd completed his training to become an electronic technician. In 1968 he completed his high-school education at the Westfalen Kolleg in Bielefeld and started his university studies in biology and medicine, both at the University of Tübingen. From 1972 until 1975 he was rewarded a scholarship of the Evangelisches Studentenwerk Villigst. In 1977 he received his diploma in biology and in 1981 his approval as medical doctor MD. From 1981 until 1986 Grodd was a resident physician in the Department of Medical Radiology at the University of Tübingen augmented in 1984–85 by a research fellowship from the Deutsche Forschungsgemeinschaft to work with the Department of Radiology at the University of San Francisco.
In 1987, Grodd shifted to the Department of Neuroradiology at the University of Tübingen, where he worked as a senior physician from 1991 until 1995. In 1991 he qualified himself as a German professor in the discipline of radiology/neuroradiology by presenting his research findings on the topic of "Experimental and clinical investigations on selective proton spectroscopy of the human brain". In the same year he attained lectureship status for the subject of neuroradiology. From 1995 until his retirement in 2010, he was professor and head of the section of Experimental Magnetic Resonance of the Central Nervous System of the University Hospital of Tübingen. Grodd is an independent researcher at the department High-field Magnetic Resonance of the Max Planck Institute for Biological Cybernetics. Clinical use of proton spectroscopy Maturation and metabolic diseases of children's brains Functional imaging of fear, sociopathy and laughing Memory performance in Alzheimer's disease and dementia Language processing and speech production Functional anatomy of cerebellum and thalamus Using functional magnetic resonance imaging, Grodd was able to demonstrate somatotopic activation areas for the motor activities of lips, tongue and feet in the cortex of the cerebellum.
Cognitive processing of visual processes For his scientific research activity, Grodd was awarded the "Kurt-Decker Award" of the German Society for Neuroradiology in 1988, 1989, 1992 and in 1998. In 1989 the German Society for Neurotraumatology honored him for his outstanding scientific work. Grodd is member in various national and international scientific organizations: since 1988 International Society of Magnetic Resonance in Medicine since 1988 European Society of Magnetic Resonance in Medicine and Biology since 1996 Organization for Human Brain Mapping since 1998 American Society of Advancement of Science since 2000 German Society of Clinical Neurophysiology since 2001 Society for Neuroscience Grodd ist author and co-author of more than 250 publications in neuroscientific journals and 26 chapters in monographs and books. List of publications Wolfgang Grodd, ResearchGate list of publications Wolfgang Grodd, PubMed MPG Tübingen Wolfgang Grodd
A nerve is an enclosed, cable-like bundle of nerve fibres called axons, in the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses called action potentials that are transmitted along each of the axons to peripheral organs or, in the case of sensory nerves, from the periphery back to the central nervous system; each axon within the nerve is an extension of an individual neuron, along with other supportive cells such as Schwann cells that coat the axons in myelin. Within a nerve, each axon is surrounded by a layer of connective tissue called the endoneurium; the axons are bundled together into groups called fascicles, each fascicle is wrapped in a layer of connective tissue called the perineurium. The entire nerve is wrapped in a layer of connective tissue called the epineurium. In the central nervous system, the analogous structures are known as tracts; each nerve is covered on the outside by a dense sheath of the epineurium. Beneath this is a layer of flat cells, the perineurium, which forms a complete sleeve around a bundle of axons.
Perineurial septae subdivide it into several bundles of fibres. Surrounding each such fibre is the endoneurium; this forms an unbroken tube from the surface of the spinal cord to the level where the axon synapses with its muscle fibres, or ends in sensory receptors. The endoneurium consists of an inner sleeve of material called the glycocalyx and an outer, meshwork of collagen fibres. Nerves are bundled and travel along with blood vessels, since the neurons of a nerve have high energy requirements. Within the endoneurium, the individual nerve fibres are surrounded by a low-protein liquid called endoneurial fluid; this acts in a similar way to the cerebrospinal fluid in the central nervous system and constitutes a blood-nerve barrier similar to the blood-brain barrier. Molecules are thereby prevented from crossing the blood into the endoneurial fluid. During the development of nerve edema from nerve irritation, the amount of endoneurial fluid may increase at the site of irritation; this increase in fluid can be visualized using magnetic resonance neurography, thus MR neurography can identify nerve irritation and/or injury.
Nerves are categorized into three groups based on the direction that signals are conducted: Afferent nerves conduct signals from sensory neurons to the central nervous system, for example from the mechanoreceptors in skin. Efferent nerves conduct signals from the central nervous system along motor neurons to their target muscles and glands. Mixed nerves contain both afferent and efferent axons, thus conduct both incoming sensory information and outgoing muscle commands in the same bundle. Nerves can be categorized into two groups based on where they connect to the central nervous system: Spinal nerves innervate much of the body, connect through the vertebral column to the spinal cord and thus to the central nervous system, they are given letter-number designations according to the vertebra through which they connect to the spinal column. Cranial nerves innervate parts of the head, connect directly to the brain, they are assigned Roman numerals from 1 to 12, although cranial nerve zero is sometimes included.
In addition, cranial nerves have descriptive names. Specific terms are used to describe their actions. A nerve that supplies information to the brain from an area of the body, or controls an action of the body is said to "innervate" that section of the body or organ. Other terms relate to whether the nerve affects the same side or opposite side of the body, to the part of the brain that supplies it. Nerve growth ends in adolescence, but can be re-stimulated with a molecular mechanism known as "Notch signaling". If the axons of a neuron are damaged, as long as the cell body of the neuron is not damaged, the axons would regenerate and remake the synaptic connections with neurons with the help of guidepost cells; this is referred to as neuroregeneration. The nerve begins the process by destroying the nerve distal to the site of injury allowing Schwann cells, basal lamina, the neurilemma near the injury to begin producing a regeneration tube. Nerve growth factors are produced causing many nerve sprouts to bud.
When one of the growth processes finds the regeneration tube, it begins to grow towards its original destination guided the entire time by the regeneration tube. Nerve regeneration is slow and can take up to several months to complete. While this process does repair some nerves, there will still be some functional deficit as the repairs are not perfect. A nerve conveys information in the form of electrochemical impulses carried by the individual neurons that make up the nerve; these impulses are fast, with some myelinated neurons conducting at speeds up to 120 m/s. The impulses travel from one neuron to another by crossing a synapse, the message is converted from electrical to chemical and back to electrical. Nerves can be categorized into two groups based on function: An afferent nerve fiber conducts sensory information from a sensory neuron to the central nervous system, where the information is processed. Bundles of fibres or axons, in the peripheral nervous system are called nerves, bundles of afferent fibers are known as sensory nerves.
An efferent nerve fiber conducts signals from a motor neuron in the central nervous system to muscles. Bundles of these fibres are known as efferent nerves; the nervous system is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body. In vertebrates it consists of two main par