In an organism, circulation is the flowing of sap or blood through the veins or channels, by means of which the perpetual and simultaneous movements of composition and decomposition manifested in organic life are carried on. Although Galen, who had observed the opposite directions of the blood in the arteries and veins, may be said to have been upon the very point of discovering the circulation, the discovery was reserved for William Harvey, who in 1628 pointed out the continuity of the connections between the heart, arteries, and veins, the reverse directions taken by the blood in the different vessels, the arrangements of valves in the heart and veins so that the blood could flow only in one direction, and the necessity of the return of a large proportion of blood to the heart to maintain the supply.
In 1661 Malpighi exhibited microscopically the circulation in the web of a frog's foot, and showed that the blood passed from arteries to veins by capillaries or intermediate vessels. This finally established the theory with regard to animals, but the movements of sap in vegetables were only traced with difficulty and after numerous experiments.
Many physiologists were reluctant to ascribe the term 'circulation' to this portion of the economy of plants; but though sap, unlike the blood, does not exhibit movements in determinate vessels to and from a common centre, a definite course is observable. In the stem of a dicotyledonous tree, for example, the sap describes a sort of circle, passing upwards from the roots through the newer woody tissue to the leaves, where it is elaborated under the action of air and light; and thence descending through the bark towards the root, where what remains of it is either excreted or mixed with the new fluid, entering from the soil for a new period of circulation.
In infusorial animalcules the movement of the fluids of the body is maintained by that of the animal itself and by the disturbing influence of nutritive absorption. In the Coelentera (zoophytes, etc) the movement receives aid besides from the action of cilia on the inner walls of the body. The Annelids, as the earth-worm, possess contractile vessels traversing the length of the body. The Insects, Crustaceans, Myriapods, and Spiders have a dorsal tube, a portion of which may be specially developed as a heart. The blood is driven to the tissues, in some cases along arterial trunks, being distributed not in special vessels, but simply through the interstices of the tissues. From the tissues it is conveyed, it may be by special venous trunks to a venous sinus which surrounds the heart and opens into it by valvular apertures. The Mollusca have the heart provided with an auricle and a ventricle, as in the snail and whelk; two auricles, one on either side of the ventricle, as in the fresh-water mussel; or two auricles and two ventricles, as in the ark-shells. Among the ascidians, which stand low in that division of animals to which the molluscs belong, the remarkable phenomenon is encountered of an alternating current, which is rhythmically propelled for equal periods in opposite directions.
All vertebrated animals (except Amphioxus) have a heart, which in most fishes consists of an auricle and ventricle, but in the mud-fishes (Lepidosiren) there are two auricles and one ventricle; and this trilocular heart is found in the amphibians, and in most reptiles except the crocodiles, which, like birds and mammals, have a four-chambered organ consisting of two auricles and two ventricles. In these two last-named classes the venous and arterial blood are kept apart; in the trilocular hearts the two currents are mixed in the ventricle. Research Circulation
Claudius Galenus (Claudius Galen) was an ancient Greek medical writer and physician. He was born in 130, at Pergamus in Asia Minor and died in 200. His father, Nicon, an architect and mathematician, gave him a careful education, and he studied under physicians in Smyrna, Corinth, Alexandria, etc, afterwards visiting Cilicia, Phoenicia, and Palestine. He returned in 103 to Pergamus, where he received a public appointment, but five years later went to Rome, and there acquired great celebrity by his cures.
Driven thence by envy, he again travelled for some time and resumed his labours in his native town, but was soon after invited to Aquileia by the Emperors Marcus Aurelins and Lucius Verus in 169.
He followed Marcus Aurelius to Rome, and appears to have remained there for some years before finally retiring to Pergamus. The closing part of his life, however, is obscure. One Arabic writer says that he died in Sicily, and Suidas states that he died at the age of seventy, and accordingly in the year 200 or 201, but it is not improbable that he lived longer.
The writings attributed to Galen include eighty-three treatises acknowledged to be genuine, forty-five manifestly spurious; nineteen of doubtful genuineness, and fifteen commentaries on different works of Hippocrates, besides a large number of short pieces and fragments, probably in great part spurious. The most valuable of his works were those dealing with anatomy and physiology, and he was the first to establish the consultation of the pulse in diagnosis and prognosis. Untill the middle of the 16th century his authority in medicine was supreme. Research Claudius Galen
Galenists was the name of the body of controversialists who, appealing to the authority of Claudius Galen, opposed the introduction of chemical ;md alchemical methods of treatment into medicine. They adhered to the ancient formulas, which prescribed preparations of herbs and roots by infusion, decoction, etc, while the chemists professed to extract essences and quintessences by calcination, digestion, fermentation, etc. Neither body possessed a monopoly of the truth, and modern medicine combines the better elements in each method. Research Galenists
Johann Baptist Van Helmont was a Belgian chemist. He was born in 1577 at Brussels and died in 1644. At the age of seventeen he gave public lectures on surgery at Louvain. After teaching medicine at Louvain, perceiving the defects of the system of Galen, he announced his intention of reforming' medicine, but finally renounced its practice, and travelled for ten years. He turned his attention to chemistry, settling at Vilvode, near Brussels in 1609, where for thirty years he practised medicine gratuitously. The emperors Rodolph II, Matthias, and Ferdinand II, invited him to Vienna, but he preferred the independence of his laboratory. Although his philosophical conceptions were of a metaphysical and empirical nature, he added greatly to the development of chemistry by employing with great advantage experimental methods. He is accredited with the discovery of sulphuric acid and the first use of the term 'gas' and also the scientific use of the thermometer. His interest in medicine led him to study the fluids of the human body. Research Johann Helmont
In the literal sense, anatomy means simply a cutting up, but is now generally applied both to the art of dissecting or artificially separating the different parts of an organized body (vegetable or animal) with a view to discover their situation, structure, and economy; and to the science which treats of the internal structure of organized bodies. The branch which treats the structure of plants is called vegetable anatomy or phytotomy, and that which treats of the structure of animals animal anatomy or zootomy, a special branch of the latter being human anatomy or anthropotomy.
Comparative anatomy is the science which compares the anatomy of different classes or species of animals, as that of man with quadrupeds, or that of quadrupeds with fishes; while special anatomy treats the construction, form, and structure of parts in a single animal. The special anatomy of an animal may be studied from various standpoints: with relation to the succession of forms which it exhibits from its first stage to its adult form (developmental or embryotical anatomy), with reference to the general properties and structure of the tissues or textures (general anatomy, histology), with reference to the changes in structure of organs or parts produced by disease and congenital malformations (morbid or pathological anatomy), or with reference to the function, use, or purpose performed by the organs or parts (ideological or physiological anatomy).
According to the parts of the body described the different divisions of human anatomy receive different names; as, osteology, the description of the bones; myology, of the muscles; demology, of the ligaments and sinews; splanchnology, of the viscera or internal organs, in which are reckoned the lungs, stomach, and intestines, the liver, spleen, kidneys, bladder, pancreas, etc. Angiology describes the vessels through which the liquids in the body are conducted, including the blood-vessels, which are divided into arteries and veins, and the lymphatic vessels, some of which absorb matters from the bowels, while others are distributed through the whole body, collecting juices from the tissues and carrying them back into the blood. Neurology describes the system of the nerves and of the brain; dermatologytreats of the skin.
Among anatomical labours are particularly to be mentioned the making and preserving of anatomical preparations. Preparations of this sort can be preserved (1) by drying them and clearing away all muscular adhesions, etc, as is done with skeletons, the bones of which are sometimes washed with acids to give firmness and whiteness; (2) by putting them into liquids, as alcohol, spirits of turpentine, etc, as is done with the intestines and other soft parts of the body; (3) by injection, which is used with vessels, the course and distribution of which are to be made sensible and the shape of which is to be retained; (4) by tanning and covering with a suitable varnish, as the muscles.
Among the ancient writers or authorities on human anatomy may be mentioned Hippocrates the younger who lived between 460 and 377 BC, Aristotle who lived between 384 and 322 BC, Herophilus and Erasistratus of Alexandria who lived about 300 BC Celsus who lived between 53 BC and 37 AD, and Galen of Pergamus who lived between 140 and 200, the most celebrated of all the ancient authorities on the science. From his time until the revival of learning in Europe in the fourteenth century anatomy was checked in its progress.
In 1315 Mondino, professor at Bologna, first publicly performed dissection, and published a System of Anatomy, which was a text-book in the schools of Italy for about 200 years. In the sixteenth century Fallopio of Padua, Eustachi of Venice, Yesalius of Brussels, Varoli of Bologna, and many others, enriched anatomy with new discoveries. In the seventeenth century Harvey discovered the circulation of the blood, Asellius discovered the manner in which the nutritious part of the food is conveyed into the circulation, while the lymphatic system was detected and described by the Dane T. Bartoline.
Until 1832 the law of Great Britain made very insufficient provision for enabling anatomists to obtain the necessary supply of subjects for dissection. An act of some years previously had, it is true , empowered a criminal court, when it saw fit, to give up to properly qualified persons the body of a murderer after execution for dissection. This, however, was far from supplying the deficiency, and many persons, tempted by the high prices offered for bodies by anatomists, resorted to the nefarious practice of digging up newly-buried corpses, and frequently, as in the case of the notorious Burke and Hare of Edinburgh, to murder. To remedy these evils a statute was passed in 1832, which made provision for the wants of surgeons, students, or other duly qualified persons, by permitting, under certain regulations, the dissection of the bodies of persons who die friendless in alms-houses, hospitals, etc. The act also appointed inspectors of anatomy, regulated the anatomical schools, and required persons practising the operations to obtain a license. Relatives had a right under the law to effectually object to the anatomical examination of a body even though the deceased had expressed a desire for it.
Embryology is the branch of biology comprising the history of animals from the first appearance of organization in the egg or ovum (the embryo stage) up to the attainment of the perfect form. The importance of the study partly depends upon the fact that the history of animals thus traced reveals the existence of structures which disappear at a later period, or become obscured by arrest of their development, or by union with other parts, and permits us to follow the steps by which complex organs arise by the combination of simpler parts. Thus points of affinity are detected between species and orders whose adult aspect is very unlike. As a systematic study embryology dates only from the 19th century, though Aristotle and Galen had considered the subject, and though Harvey and other later physiologists did much in the way of direct observation to lay the foundations of higher work. Research Embryology
Galenism is a system of medicine based on the 84 surviving technical treatises of Galen, including the theory of the four bodily humours. Research Galenism
The Van Galen was a Dutch destroyer of 1316 tons displacement launched around 1929 and sunk by German aircraft in 1940 during the Second World War. The Van Galen was powered by three Yarrow oil-fired boilers providing a top speed of 36 knots. She was armed with four 4.7 inch guns; one 3 inch anti-aircraft gun; four 40 mm anti-aircraft guns; four 12.7 mm anti-aircraft guns; one machine-gun; four depth charge throwers and six 21 inch torpedo tubes arranged in two triples. Research Van Galen
The Van Galen is a Dutch multi-purpose Karel Doorman Class frigate used for anti-submarine warfare, anti-surface operations and air defence. The ship is equipped with two quad launchers for the AGM-84 (Harpoon) Block 1C anti-ship missile. For short-range air defence, the ship has a Mk 48 vertical launch system for the Raytheon Sea Sparrow (RIM-7M) missile, and carries 16 missiles. The ship's main gun is a 76 mm Otobreda Mk 100 which is capable of firing 100 rounds per minute with a range of 16 km anti-surface and 12 km anti-air. The Signaal Goalkeeper close-in weapon system (CIWS) is fitted to provide close-in air defence. Also fitted are two Oerlikon 20 mm light cannon which fire at 800 rounds per minute to a range of 2 km. Two twin Mk 32 Mod 9 torpedo tubes are fitted and they fire the Honeywell Mark-46 Mod 5 lightweight anti-submarine torpedoes. The ship carries one GKN WestlandLynx SH-14D helicopter for anti-submarine warfare (ASW). Research Van Galen II
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Abbreviations
Research Circulation
