theory

(the’o-re) (Gr. Oewpia]. 1. The doctrine of the principles underlying the art of healing as distinguished from the practice of that art. 2. A formulated hypothesis, or, loosely speaking, any hypothesis or opinion not based upon actual knowledge. Adami’s t., a hypothesis for the explanation of heredity, resembling Ehrlich’s side-chain theory of immunity. In this hypothesis it is a umed that the idioplasm, or vital protoplasm, is made up of a ma of molecules which form a central ring from which side-chains may be detached or to which they may become attached without alteration of the primitive center. Environment causes the central ring to have attached certain side-chain combinations, and in this way the modification of the ti ue-cells are brought about. Environment also leads to other modifications in the form of new side-chain combinations. Altmann’s t., a theory that protoplasm is made up of granular particles (bioblasts) grouped in ma es and enclosed in indifferent matter. apposition t., the theory that ti ues grow by the deposit of cells from without. atomic t., the theory that the molecules of a substance are made up of one or more atoms, each representing a definite amount of the ele ment, which amount does not vary in the mole cule, whatever combinations the molecule may enter. avalanche t., the theory that nervous influence increases in force as it descends along an efferent nerve. biochemic t. See Ekrisch’s biochemic t. Bowman's t. (of urinary secretion), the theory that in the glomeruli, water and inorganic salts are produced, while the urea and related bodies are eliminated by the epithelia i cells in the convoluted tubes. Cf. Ludwiy’s ¢. brunonian t., the obsolete opinion of John Brown (1735-1788) that all diseases are due to an exce or lack of stimulus. Buchner’s t., a theory of immunity which supposes that the cells of a body which has recovered from an infection undergo a reactive change which protects against similar infections. cell-chain t., the theory that the nerve-fiber consists of a chain of special cells which have only secondarily been brought into relation with the central cell. cloaca t., the theory a umed by children and some neurotics that a child is born like a pa age of the bowels. Cohnheim’s t., the theory that the emigration of the leukocytes was the e ential feature of inflammation. corpuscular t., the theory that light consists of minute particles of matter given out in all directions from a luminous body. darwin i an t. See dariinism. De Vries’ t. See. of mutations. Dieulafoy’s t., the theory that appendicitis is always due to the appendix becoming a closed cavity. Ehrlich’s biochemic t., the theory that specific chemic affinity exists between specific living cells and specific chemic substances. Ehrlich’s side-chain t., E.’s lateral-chain t., a theory advanced regarding the phenomena concerned in immunity and cytolysis. According to this theory, the protoplasm of the body-cells contains highly complex organic molecules, consisting of a tolerably stable central group, to which are attached le stable “lateral chains” (or “side chains”) of atoms or atomic groups. The ordinary chemic trans for- mations in the protoplasm are carried on by means of these lateral chains (or receptors), the stable center of the molecule remaining unaffected. The lateral chains contain a group of atoms (haplophore group), which is capable of uniting with similar groups (haptophore groups) in toxins, bacterial cells, and foreign cells. As the lateral chains of the cell protoplasm are seized upon by the foreign cells, the stable central group is stimulated to produce new lateral chains (receptors), which are formed in exce and thrown off into the body juices. These side chains that have been thrown off constitute intermediary bodies or ceptors. The intermediary bodies (called also ceptors, haptine, immune body, sensitizer, fixative, preparative, and desmon) are designated, according to their nature, as uniceptors and amboce ptors. The uniceptors, represented by the antitoxins, are single bodies, and produce their effect by seizing and anchoring the toxin by means of its haptophore group. The amboce plors, represented by the cytolysins and bacteriolysins, have two affinities, one-for the invading bacteria or foreign cells, and one for a body called the complement, end-body, or addiment, which exists normally in the body-juices. The complement, when united with the bacteria or foreign cells through the medium of the amboceptor, is capable of causing solution of the bacteria or cells by means of a toxophore or symotoxic group. emigration t. Same as Cohnheim's t. Flourens’ t., the opinion that the entire cerebrum is concerned in each and every psychic operation or proce . Frerich’s t., the theory that uremia is really a poisoning by ammonium carbonate formed by the action on urea of a ferment contained in the blood. Freud’s t., hysteria is due to a psychic trauma which was not adequately reacted to when it was received, and remains as an affect memory. germ-t. 1. The doctrine that all organisms are developed from a cell. 2. The doctrine that infectious diseases are of microbic origin. Glénard’s t., the theory that abdominal ptosis is a nutritional disease with atrophy and prolapse of the intestine. Cf. Stiller's ¢. Golgi’s t., the theory that the neurons communicate by the neuraxons of Golgi’s cells and the collaterals of the neuraxons of Deiters’ cells. Golt’s t., the theory that the function of the semicircular canals is to transmit sensations of position, and thus materially aid in the sense of equilibrium. ground-water t. Pettenkofer’'s t. Hammarsten’s t., that the coagulation of the blood is due to the decomposition of fibrinogen and the production from it of fibrinogen by the agency of fibrin. Helmholtz t., a theory of sound perception: each basilar fiber responds sympathetically to a definite tone and stimulates the hair-cells of Corti’s organ, which rest upon the fiber. The nerve impulse from this stimulation of the hair-cells is carried to the brain. Hering’s t., the doctrine that color sensation depends on decomposition and restitution of the visual substance: disa imilation producing red, yellow, and white, and restitution producing blue, green, and black. Huguier’s t., uterine prolapse is usually due to lengthening of the supra vaginal part of the cervix. humoral t., the theory that the body contains four humors—blood, phlegm, yellow bile, and black bile, a right proportion or mixing of which constitutes health; improper proportion or irregular distribution constitutes disease. Kern plasma relation t., the theory that for each cell there exists a definite size relation of nuclear ma to cell ma . Lamarck’s t., the theory that acquired characteristics may be transmitted. Liebig’s t., the hydrocarbons which oxidize easily are the foods which produce animal heat. Ludwig’s t. (of urinary secretion), the theory that urine is formed by the simple proce of filtration in the glomeruli _and diffusion along the urinary tubules. Mac- Dougal’s t., the hypothesis that many, if not all, variations in nature are formed by chemic modi-