STIMULANTS. 675 STING-RAY. with Gk. (TTl^eiP. slizein, to pierce, Skt. tij, to be sharp, OHG. stchhan, Ger. stechen. Eng. stick). Agents which incre.ise tempor.Trily the functional activity of the organism as a whole or of the various organs of the body. These may be cardiac, respiratory, nervous, hepatic, renal, gas- tric, etc.. depending on the organ or system all'ect- ed. Stimulants embrace a wide range of thera- peutic agents, but popularly the term is applied to those acting especially on the circulatory, res- piratory, and nervous systems. Alcohol is the most generally employed, in the form of whisky, brandy, or wiues. The various preparations of ammonia, inhaled or given as the aromatic spirits of ammonia, are very serviceable diffusable stimu- lants. Ether may be taken as an inhalation, a hypodermic injection, or in solution by the mouth, and acts rapidly. Among the other general stimulants may be mentioned camphor, stiyeh- nine. lavender, ginger, pep])ermint oil, and the other essential oils. This class of remedies is useful in fainting, hysteria, shock, and similar conditions. STIMULUS (from Lat. stimulus, goad, in- citement). A mechanical, molecular, chemical, or ethereal change in the conditions external to a plant cell or to the plant bodj^ which pro- duces a change (reaction) in the cell, a particular organ, or the whole plant. Jlechanical stimuli, due to the mass movement of the external agents, are contact, pres.sure, traction, friction, torsion, etc. ( See IIovemext ; Thigmotropism : Tendril. ) In the absence of knowledge as to its nature, gravity may be included in this group, since it depends upon the mass of the body acting (the earth), although it is not in itself mechanical. (See Geotropism.) Jlolecular stimuli depend upon molecular movements. Osmotic pressure has been proved capable of acting as a stimulus. The reactions of organisms to solutions of vary- ing concentration are interpreted as due not to the chemical nature but to the number or impact of the solute molecules, since they are alike with all substances of the same osmotic pressure. ( See OSHO.SIS. ) Chemical stimuli depend not upon the mass, but upon the chemical composition of the body acting. They are, therefore, almost as various as chemical compounds, although many substances are nearly or quite inert. The most common acting upon plants are water, organic acids, mineral salts and other solutes in the water. (See Chemotropism.) Ethereal stimuli are propagated in the ether, light and heat. (See Heliotropism : Tiierjiotropism.) Here also may be included electricity, whose action in nature is little understood. (See Irritability.) STINDE, stin'de, JmJtJS (1841—). A Ger- man humorist. He studied and practiced chemistry', became editor of a Hamburg trade journal, contributed to periodicals, and was gradually drawn wholly to literature, wherein he won popularitv by Buchlwlzeus in Italien (188.3), Die Famllie Buclihoh (1884, translated), a second part of this (1886), Frau Buchholz im. Orient (1888). Frau Wilhelmine Buchholz' Memoiren (1895), and Hotel Buchholz, AussteUunftserlehnisse (1800). His other writ- ing, dramatic and otherwise, is of slight worth, but in the Buchholz series the lower middle class of Berlin is depicted with a fresh, genial, healthy humor. STING (from AS. stingan, Goth, us-stiggan, to push out; connected with OHG. stanga, Ger. I:itangc, obsolete Eng. stang, sting). An organ possessed by various kinds of animals, by means of which they not only inflict a mechanical wound in their prey, but also insert into it an irritant or poi-sonous chemical. Stinging or nettling cells (.see Xematoctst) occur in all the Crelenterata except ctenophores, in some tuluilarian worms, and on the cerata of the nudibranch Eolis. The sting of scorpions (q.v.) is in the tail. The poison, secreted by a gland, exudes through small openings into the wound, and is powerful enough to cause death in the small natural prey. Among insects, several forms are proidcd with a sting. This org.an, which is of especial use as a means of defense to the so-called aculeate Hymenoptera, a group which includes the bees, wasps, and many ants, and to the ilutillidoe or 'cow-ants' or ' velvet ants,' is simply a modified ovipositor connected with a poison gland. The sting of a bee consists of three distinct pieces : two barbed needles and one gouge-like piece, the 'director;' the needles move up and down on the director, controlled by muscles attached to their bases. In the anterior part of the director there is a sliglit projection on the needle which catches a bit of the poisoH in the chamber and carries it to the wound. The director itself is composed of a united pair of stylets, and without the director is a third pair of stylets which are thick and hairy. (See Insect.s, section on Poisonous Insects. ) The poi- son is secreted by poison glands which pour their poison into the chamber. The poison of the bee is said to be secreted by two glands, one pro- ducing an acid and the other an alkaline fluid. Only acid poison glands are said by some in- vestigators to be present in those wasps which only stupefy the prey that they store up for the nourishment of their yoimg. STING-RAY, or STINGAREE. A ray ( q.v. ) of the family Dasyatidfe. characterized by the usual possession of a long whip-like tail, bear- TAIL OF A STISG.BAY. a, enlarged view of the base of the tail of a stinp-ray, having several epinea ; b, a single ejiine. barbed on both sides. ing near its base one or more long, strong, sharp spines retroversely serrated. ^Yhen broken off the spine is replaced by the coming forward of one of a succession growing behind it. The family includes about fifty species, inhabitants of the warmer seas, some species occurring in the fresh waters of
