Amalgams, Amanita Phalloides, and Jules Amar

AMALGAMS (from Greek malassein—to soften), alloys of metals with mercury, are obtained 1) by direct dissolution of finely divided metals in heated mercury (Na, K, Ag, Au, Sn, Zn, Pb, Bi, Ca, Cu) or 2) by treating solutions of metal chlorides with sodium amalgam (Fe, Mn, Co, Ni); a characteristic feature of amalgams is their low melting point. Of the individual amalgams, those of practical use are: 1) sodium amalgam, used in organic synthesis for reduction; 2) tin-mercury alloys, used in the manufacture of mirrors; 3) amalgams of cadmium, cadmium and tin, as well as tin and silver, for the manufacture of dental fillings; 4) alloys containing mercury, cadmium, bismuth, tin, and lead, which are used in the preparation of anatomical specimens; 5) gold and silver amalgams, which are used in the extraction of these metals from placer deposits. Regarding the aspects of occupational hazards when working with amalgams, see Mercury. Dental amalgam consists of plastic, hardening materials for filling teeth. It contains mercury and one or more metals (copper, silver, tin, zinc, gold, platinum, cadmium); the components are mixed in the appropriate proportion and ground in a mortar to the consistency of a paste. The advantages of amalgam fillings are their density, hardness, and resistance to oral fluids. Negative properties include the instability of the filling's volume due to its gradual contraction or expansion, thermal conductivity, and the ability to darken and stain the tooth. By composition, one distinguishes copper, silver, gold, and platinum amalgams; a minor admixture of gold (5–7%) or platinum (2%) prevents the filling from darkening. In 1926, the chemist Stock established through laboratory methods that amalgam fillings constantly release Hg and expressed the conviction that they could cause general poisoning of the organism. Other authors refute this assertion; Fenchel and Tamman proved that amalgam fillings release a negligible amount of Hg during the first 10–15 days; after this period, they contain no free mercury. Professor Agapov (Irkutsk), having examined the urine of 50 individuals with a large number of amalgam fillings, did not detect traces of Hg in any case. AMANITA PHALLOIDES PERS., a genus of gilled mushrooms from the family Agaricaceae, to which the most poisonous mushrooms belong. The most poisonous is A. phalloides (Fr.) Quel., the death cap, or false champignon. Poisoning is often fatal. The cap is pale, greenish or yellowish; the stalk has a leathery ring, is thickened at the base, and surrounded by a large volva. The gills are white. It is often confused with the champignon, which, however, is easily distinguished by its brown gills and the absence of a volva. It is widespread in deciduous forests throughout Europe. Less poisonous, but also very dangerous, is A. muscaria (L.) Pers., the fly agaric, easily distinguished by its bright red cap with white warts. It contains the alkaloids amanitin and muscarine. It is widely distributed in deciduous, especially birch, forests. The Kamchadals prepare an intoxicating drink from it. Also poisonous are the species A. virosa (Fr.) Sacc. and A. umbrina (Pers.) Schrot. AMAR, Jules (Jules Amar), a prominent French researcher in the field of the physiology of labor. Before the war, he worked in the field of the energetics of labor in Paris at the Conservatoire des Arts et des Métiers. He wrote many articles and books on these issues; the most famous is "Le moteur humain" (awarded an honorary mention by the French Ministry of Labor), which is available in Russian translation under the title "The Human Machine." During the war, he developed issues of rationalizing prostheses for the wounded. Amar proposed a physiological method for determining professional aptitude, which consists of accounting for the organism's reaction to a test task of a certain difficulty.