Page:The New International Encyclopædia 1st ed. v. 04.djvu/664

* CHEMNITZEK. 582 CHEMOTROPISM. served in the Russian Army under Peter the Great. He participated in the eaiiipaigns of the Seven Years' War and afterwards devoted himself to mining eiigincirinj;, and suliso(|uently visited (iormany, lluHand, and Franco. Upon his return he accepted a ]iosiliou as consul to Smyrna, where an attack of melancholia hastened his death. In contradistinetitm to SumarokolV and others among the earlier fabulists of Russia, whose works are essentially satires, Chemnitzer was the first to introduce the genuine fable into Kussian literature. Although to some extent translations or imitations of La Fontaine and Gellert, his works show considerable origi- nality, and their good-humor, vivacity of dia logTie, simplicity, and distinctively national eharact<T have greatly endeared them to the Russian jieople. The latest and best edition of his works is that of Grot (Saint Petersburg, 1873). CHEMOSH, ke'mosh. The national god of the Aloabites, mentioned as such in the Bible (Num. xxi. 29; Jer. xlviii. 46) and on the Jloab- ite Stone. He bears the same relation to the Moabites as the national deity Yahweh does to the Hebrews. Little is known of the worship of Chenio.-.li ; the Jloabite Stone tells that llesha, King of Moab, built a high place for the wor- ship of his god ; and when Solomon, as a politi- cal symbol of his control over surrounding na- tions, introduced the oiBeial eults of other deities by the side of the national Yahweh. he also built a high place in Chemosh's honor. From the fact that the King of the Moabites offered up his son to the god (11. Kings iii. 27), it has been conjectured that human sacrifices formed part of the worship of Chemosh. The Amorites are apparently said to have worshiped Chemosh (Judges xi. 24), but the passage (Judges xi. 12-28) in which this statement occurs is probably an interpolation, and should refer to Moab. Chemosh was formerly variously identified with Saturn or Mars, but these identi- fications have no value. The etymology of the name is not known. CHEM'OTAX'IS (Neo-Lat., from Gk. xwda, chemeid, alchemy -j- rnsir, taxis, arrangement, from Taaci-iv, tassein. to arrange). The sensitive- ness of free-swimming organisms to certain chemical substances, by virtue of which they ap- proach or recede from the source of the su!i- stanee. Chemotaxis seems to be fundaTucntally the same as chemotropisni (q.v.). though the re action is unlike. It has been held that in many organisms the une(]ual stimulation of diirercnt parts of the creature by the diffusing chemical substance causes the motor organs, on one side to act more strongly than tlio.se on the other. Thus, the body is swung arotmd in the medium until it is so placed that all sides are equally stimulated. This condition occurs only when the axis of the organism eoincddes with some of the lines of diffusion of the stimulating chem- ical ci>nii)ound. Since the motor organs still act, but now equally on all sides, swinuning must take place cither toward or away from tli« source of diffusion. !More recent study, however, has shown that with certain substances the or- ganisms, swimming in all directions, accidentally pass into the constantly increasing sphere of in- fluence of the diffusing substance; hut as they swim through it, reach the limit, and are about to pass out into the pure solvent again, a re- action occurs which reverses the movement of the motor organs. The creatures thus seem to re- bound from the invisible limit whenever they reach it. The region occupied by the diffusing substance therefore acts as a tra|) into which they may pass but from which they cannot escape. t)lher substances repel a given organ- ism. In this case the reversal of motion occurs as soon as they reach the boundary of the region occupied by the diffusing particles. (hemotactic sensitiveness is observed, among plants, in zoospores of various algu' and fungi, in sperms of mosses and ferns, and in many bac- teria. Fern-sperms are attracted by malic acid and its salts, as well as by many salts of the common mineral acids. Sperms of mosses are attracted by cane-sugar. Such reactions may be demonstrated as follows: Very fine capillary glass tubes are prepared, of such diameter that the sperms can swim easily into them. These are cut into lengths of about one centimeter, and one end of each is sealed in the flame. These tubes are submerged in the solution to be tested, and the whole is exhausted of air tnider an air- pump. Air is then allowed to reenter the re- ceiver, and the fiuid is forced into the tubes, leaving only a small bubble of air at the closed end. A drop of water containing the sperms is now mounted on a microscopic slide in the ordi- nary way. The tubes just described are placed under the edges of the cover-glass, their open ends inside. After a short time the sperms may be observed swimming toward and into the tubes, or away from them. The mode of response of an organism is profoundly influenced by the con- centration of the substance. CHEMOT'ROPISM (from Gk. x'/A'f'", clie- meia, alchemy + 'i>"''i. trope, a turning, from Tpivciv, trej)ein, to turn). The sensitiveness of certain plant-organs by virtue of which tht>y change the direction of their growth when acted upon by chemical substances. If an organ bends so a.s to grow toward the source of a sub- stance, it is said to be positively cliemotropic to CItKMOTROPISM. Positive clicmotropistn. rt. Hyphn? of n fundus. Mucor, enterin^f stoinii of li'iif i»f Trntlpscjiatin which tins lictTi in- Joeted with aiiinioiuiim eliloride : b, [iDlIcn-tubesof Jii^itnlis t'litcrinji stoiim of siiine. injected with 4 percent, solntiou of cane-sugar. (Aft«rMlyo8hl.) that substance ; if it turns away from it. it is negatively chemotropic. The organ tends to place itself so that it shall be c<iually stinuilatcd on all sides by the diffusing chemical substance. In elongating organs, such as root-s, fungous fila- ments, etc., the reaction is one of growth; the curvature is brought about either by the retarda- tion of growth on one side or by its acceleration on the other, or by both together. Of course the