Mud

MUD therapeutic, represents a plastic colloidal substance of the consistency of thick ointment, paste, butter, or sour cream, of black, grayish-black, or brown color. They consist of inorganic soil mass closely connected with organic substances - products of the life activity and decay of plant and animal organisms - and with living microorganisms. Characteristic of the processes of decomposition of organic substances in peat and silt muds is anaerobic decomposition not accompanied by complete oxidation. The small amounts of O₂ required for these processes are obtained by bacteria reducing mineral salts, for example CaSO₄ = = CaS + 2O₂. The reaction does not stop here, and calcium sulfide in the presence of water serves as a source of formation of H₂S, giving the characteristic smell to most therapeutic muds: CaS + 2H₂O = Ca(OH)₂ + H₂S. However, H₂S can also form directly from sulfuric acid: H₂SO₄ = = H₂S + 2O₂. As a result of biochemical processes, various compounds are formed in muds, including NH₃, amine bases and other products of protein decomposition, humic substances, fatty acids, sulfuric acid, acetic, valeric, formic acids, etc. The mechanical structure of muds is also of great importance. The more fine particles, the more plastic the mud. According to Burks, the more sand and particles with a diameter of 0.05-0.25 mm, the lower the viscosity of the mud. In addition, the presence in therapeutic muds of a significant amount of larger particles, especially sharp fragments of shells and crystals, threatens to injure the skin and makes the mud unsuitable for use or requires expensive processing (grinding, sifting, etc.). It should also be noted that dense lumps, having greater thermal conductivity than the mud mass, can cause burns. Varieties of therapeutic muds - peat, silt, and volcanic muds. - P E A T M U D S. Their main part is peat, i.e., mass obtained in the process of prolonged decay of organic substances of plant and partly animal origin and their interaction with soil, water and the mineral compounds contained in them. As a result of a series of biological processes in peat, it contains plant substances, humus and humic acid, resinous substances, silica, alumina, ferric phosphate, ferrous sulfide, common salt, sulfates, free H₂SO₄, H₂S, etc. The formation of peat occurs because the decaying plants come into prolonged contact with standing or slowly flowing water. Such conditions exist when a lowland covered with dying vegetation or a slope of an elevation is flooded with water flowing here, or when a spring coming from below saturates with water a flora-rich earth surface, or finally during the slow drying up of lakes, the water of which is gradually displaced partly by dying and partly by newly emerging vegetation absorbing large amounts of water. Microscopic algae, multiplying extraordinarily rapidly and leaving behind a delicate siliceous skeleton in colossal quantities, as well as sphagnum moss, take particularly active part in the formation of peat. For therapeutic purposes, use is made mainly of such peat mud that forms with the constant participation of mineral water from nearby sources, and sometimes also of peat that is treated with mineral water only before use. Silt muds represent sedimentary formations at the bottom of seas, lagoons, lakes, rivers and mineral springs, arising under the influence of the interaction of water of various mineral composition with the constituent parts of sandy, clayey or calcareous soil, decayed remains of the flora and fauna of mineral water bodies, and with the participation of living plankton and the most diverse microorganisms. Therapeutic silt thus consists of a mineral base organically connected with the products of the life activity and decay of organic substances of animal and plant origin and impregnated with mineral water or brine. Most silt muds are distinguished by a blue-black color, which is due to the presence of ferrous sulfide formed by the action of hydrogen sulfide on iron oxide compounds: Fe₂O₃ + 3H₂S = = 2FeS + 3H₂O + S. When standing in the air, ferrous sulfide oxidizes and colors the mud mass gray due to the formation of iron oxide and the release of elementary sulfur: 2FeS + 3O₂ = Fe₂O₃ + 2S. The mud turns black again if it is left under brine for several days and thus further access of air to it is stopped. Then, as a result of the life activity of reducing microorganisms, oxygen is split off from iron oxide. Among the numerous microorganisms inhabiting therapeutic muds, sulfate-reducing bacteria play a particularly prominent role, such as Vibrio hydro-sulfureus, Microspira aestuarii, the product of whose life activity is H₂S, split off by them from organic and inorganic substances. Reacting with iron salts, H₂S forms colloidal iron hydrosulfide (hydrotroilite), giving the mud its characteristic blue-black color and valuable colloidality from a balneodynamic point of view. Excess H₂S, rising to the surface, does not completely evaporate into the air, but, meeting in the surface layers of brine a barrier zone of sulfur bacteria (filaments of Beggiatoa and others), is oxidized by them and, combining with metals, forms sulfates, which, falling to the bottom, are again reduced by sulfate-reducing bacteria, etc. (the cycle of sulfur, iron and lime). Volcanic muds are close to silt muds and are divided into two groups. The first group consists of muds whose origin is connected with actual volcanoes. Volcanic vapors rising from great depths or "juvenile" mineral water released by cooling magma, passing through layers of clay, limestone, volcanic ash and other rocks, soften these rocks and turn them into a viscous mud, which together with water vapor and mineral water is thrown to the surface. These muds are characterized by high temperature and a high content of H₂S and CO₂. Mud volcanoes forming such muds are especially common in Italy, Sicily and Iceland. To this group of volcanic muds also belongs the Italian "fangh". The second group includes muds of the so-called mud cones (also called "salzami", and on the Taman and Kerch peninsulas "blevakami"), which represent low cones with an opening at the top, from which various gases are released and periodically black-blue and gray liquid mud is erupted. Mud of this origin is characterized by a relatively low temperature, a small amount of water vapor, and a predominance of hydrocarbons over other gases. Such mud volcanoes are usually found in the immediate vicinity of oil deposits. Their origin is most likely explained by the fact that together with oil, gaseous hydrocarbons are always present in the rock layers, which break through the enclosing rocks to the earth's surface. Main differences between peat and silt muds. Color: peat muds have a brown, dark brown and brownish-gray color, which changes relatively little in the air, while silt muds are usually black, and only in some cases, if they form in the presence of fragments and detritus of shells, they have a gray color. Peat and silt muds also differ from each other in consistency. Peat muds form a dense dough-like mass which, as it dries, begins to crumble and turns into loosely connected, easily crushed lumps. Silt muds are characterized by an ointment-like consistency, determined by the colloids of the mud. The viscosity of silt muds is also due to their colloidality. They adhere tightly to the body and are difficult to wash off. When drying, silt muds turn into powder. The reaction of peat muds is sharply acidic; silt mud, on the contrary, has an alkaline reaction. In peat muds, the basis of which is decayed plants, there are more organic substances than in silt muds, the formation of which occurs in sandy-clay or sandy-calcareous soil. The specific gravity of peat and silt muds is different. In general, ready-to-use peat mud has a specific gravity below 1.2, while silt mud has a specific gravity above 1.3. The thermal conductivity of peat mud is significantly lower than that of water, while silt muds have, on the contrary, increased thermal conductivity, sometimes twice that of water. The colloidality of silt muds is significantly higher than that of peat muds. There is a significant difference in the methods of processing silt and peat muds for therapeutic purposes. The former is protected from prolonged contact with air, because from this contact it loses not only its color but also partly its colloidality. These properties are restored only after regeneration of the mud under brine or mineral water.

The second type, on the contrary, is subjected to prolonged exposure to the air before use, with the aim of converting many insoluble compounds into soluble ones through oxidation. For this purpose, the peat mass is cut into cubes and left on specially adapted platforms that facilitate air access to the mud from all sides for 7-9 months and even for 1-2 years. The dried peat is freed from un-decayed roots, stones, and other coarse impurities by sifting, screening, and grinding. The powder obtained in this way is mixed with mineral water and turned into a pasty mud mass used for therapeutic purposes. Mud of the silt type usually does not require such thorough preparation, as it is extracted from deposits mostly in a form ready for use. There also exist muds of a mixed type, silt-peat. Mud management includes, in addition to operational functions, the care of preserving the mud reserves and its medicinal properties for as long as possible. In some cases, it is sufficient to take measures against the deterioration of mud quality due to the drifting of coastal sand. In other cases, it is necessary to maintain at a certain level the quantity and concentration of brine or mineral water in the reservoir (see Mud Baths). In a third set of cases, it is necessary to care for the preservation of mud reserves by means of regeneration and reuse of spent mud, or even by stimulating the processes of mud formation. In Staraya Russa, since 1926, proper 4-field mud management has been practiced with the aim of increasing mud formation in 'resting' basins. Finally, familiarity with the mechanism of mud formation allows one to raise the question of artificial, so to speak, factory production of medicinal mud (Ogilvy, Carstens, Sveshnikova, Koshtoyants). In caring for regulating the salt concentration of brine in the mud basin, it must be taken into account that at low concentrations of brine, many species of the plant and animal kingdoms thrive, providing abundant organic material for mud formation, but that the processes of mud formation proceed most successfully at a brine concentration of about 16-20° Baumé, which represents optimal conditions for the development of the most important mud-forming organism Microspira aestuarii. This microorganism can also exist at higher concentrations of brine, but then unfavorable conditions are created for the reproduction of other species of bacteria and algae, and the influx of organic material ceases. Thus, the conditions of 'optimum' apparently constitute a brine concentration of about 16-20° Baumé (Predtechensky, Nadson, Fersman, Isachenko, Arnoldi, Perfilyev).