SYNTHESIS. 782 SYPHILIS. oxj'gcn and one of hydrogen, or if water could not be analyzed at all, its e.xact composition could be demonstrated by causing oxygen and hydrogen to combine. In fact, it was the synthe- sis of water by Cavendish that first indicated its chemical nature and exact composition. (See CiiEMiSTRV, historical section.) Secondly, syn- thetic methods may, and very often do, serve to reveal the complex chemical constitution of com- pounds of carbon. It is explained under C.Rbon CoMPorNDS (q.v. ) that one of the basal princi- ples employed in determining the constitution of compounds is the assumption, itself well founded on facts, that when a given compound undergoes a moderate chemical change, the greater part of each of its molecules remains unaffected: an atom, or a group of atoms, may be replaced by another, but the linking of the remaining atoms is not changed. Thus, by the action of chlorine on acetic acid, the latter may be gradually trans- formed into mono-chloracetic acid, di-ehloracetic acid, and tri-chloracetic acid, one, two, or three atoms of hydrogen in the molecule of acetic acid being replaced by one, two, or three atoms of chlorine; but the remaining atoms (carbon, hy- drogen, and oxygen) are linked in the chlor- acetic acids in the same manner as in acetic acid itself. On this principle, the constitution of a compound becomes known if it is produced by synthesis from compounds of known constitution. In this connection it may be well to observe that the definition of the term synthesis must not be taken to mean the production of compounds from thei^ elements directly. Thus, when it is said that ordinary alcohol can be produced syn- thetically, it does not mean that alcohol can be made by the direct luiion of carbon, hydrogen, and oxygen. The synthesis of alcohol consists of the following steps: carbon and hydrogen are caused to unite into acetylene (q.v.) ; acetylene is caused to unite with hydrogen into ethylene: ethylene is caused to unite with sulphuric acid to form ethyl-sulphuric acid ; and the latter by reaction with water yields alcohol. The two compounds employed, viz. water and sulphuric acid, can also be made by starting with their elements : and so it may be said that ordinary alcohol can be made with nothing to start with but elementary substances, and this is what is meant by 'the synthesis of alcohol from its elements.' Finally, many synthetic processes have acquii'ed great im- portance industrially. In 1868 Graebe and Lie- bermann built up by synthetical processes the substance called alizarin (q.v.), which occurs naturally in madder root, and which gives the latter its chief value as a dye-stuff. This arti- ficial alizarin is now made on an enormous scale and has almost entirely displaced madder in dyeing and calico-printing. In 1880 Adolf Baeyer accomplished the synthesis of indigo. In 1887 Ladenburg succeeded in the sTithesis of coniine, C,Hu^. flic poisonous alkaloid found in hemlock. Vanillin, the aromatic flavoring prin- ciple of the vanilla bean, has been made arti- ficially by several chemists. Antipyrin, a sub- stance much used in medicine, and saccharin, a substance several hundred times sweeter than sugar, are entirely the products of synthesis. Yet while most of the known carbon compounds can be produced synthetically, some of the most important organic substances, including the pro- teins and many carbohydrates, still remain un- synthesized, and hence but imperfectly under- stood, and must still be obtained ready-made from nature. The synthetic methods employed in the preparation of a large number of carbon compounds are mentioned under the special names of those compounds. For further informa- tion, consult: Berthelot, La synthise chimique (Paris, 1871) : Ger. trans., Leipzig, 1877) ; Louise, Hynthisc d'hijdrocarhures, d'acetones, d'acides, d'alcools, d'cthers et de quinoncs dans la serie aromutique (Paris, 188.5) ; Lellmann, Principien dcr organischen iii/iithese (Berlin, 1887); and especially the excellent work of Elbs, Die syn- tlictischen DarsteUunysinethoden der Kohlenstoff- Verhindungen (Leipzig. 1889-91). See Chem- istry (historical section) and Carbon Com- SYNTHETIC GEOMETRY. See Geometry. SYNTONIN (from Gk. aivrovo^, syntonos, stretched tight, from avvreivciv^ synteinein, to stretch tight, from cvv, syn, together -f- Telveiv, ieincin, to stretch). A protein substance pre- pared by the action of dilute acids on the myosin of the muscles. The acid solution thus obtained is neutralized with alkali and the precipitated syntonin is washed with a small quantitj- of water. Syntonin may be converted into a globu- lin probably identical with myosin, by dissolving in lime-water, adding ammonium chloride, then neutralizing with acetic acid ; from the solution tlius obtained the globulin may be precipitated by adding the solution slowly to a large amount of distilled water. Syntonin is soluble in lime- water and in dilute solutions of sodium carbon- ate, but not in acid sodium pliosplinte. It may be classed with the so-called acid albumins, and it is distinguished from other substances of the same class of proteids by its insolubility in acid sodium phospluite solution. SYPHAX, sl'f;-iks (Lat., from Gk. S.vipai). A Xumidian prince, who played a part in the Second Punic War, an enemy of ilasinissa (q.v.). SYPHILIS (from Syphilus. in the Latin poem entitled iSyphiliis. sice ilorhi Gallici libri trcs, by the Italian physician and poet Hieronimo Fracastoria (1483-15.53), a shepherd who was afflicted with the disease by Apollo as a punish- ment for offering homage to his king instead of to the god: of uncertain etymology, popularly explained as from Gk. <T^f, sys. hog + (p'^f'i, philos, loving, or, less plausibly, from aii syn, with + i?i'^')f, philos, loving), or Lues, or The Pox. A specific contagious disease peculiar to the human species, chronic in its course, and gen- erally acquired during sexual congress. It is always due to contact with a syphilitic indi- vidual or with his secretions or discharges. De- scriptions of syphilis are found in the earliest writings, and traces of it are discovered in the bones of prehistoric people. Chinese accoimts of it date back to the writings of HoanTi, who lived about 2637 B.C. The earliest Indian record is foimd in the Ajwe Veda of Susrutas. .v.n. 400. The .Japanese historians described the disease several thousand years ago. The Hebrews were familiar with it and it is probable that many cases called leprosy were really syphilis. Hip- pocrates and his successors describe it as it existed among the ancient Greeks, and Celsus speaks of it among the Romans. Although the malady is known to have existed in Europe at least as early as a.d. 12.50. when Theodoric. a Dominican monk, wrote of the malum mortuum
