| periodic law | The properties of elements are periodical functions of their atomic weights; i.e., if the elements are arranged in the order of their atomic weights, every element in the series will be related in respect to its properties to the eighth in order before or after it. Synonym: periodic law. (05 Mar 2000) |
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| Grasset's law | In lesions of one hemisphere, the patient's head is turned to the side of the affected muscles if there is spasticity and to that of the cerebral lesion if there is paralysis. Synonym: Grasset's law. (05 Mar 2000) |
| Ricco's law | <physics> For small images, light intensity X area = constant for the threshold. (05 Mar 2000) |
| Ritter's law | A nerve is stimulated at both the opening and the closing of an electrical current. See: law of polar excitation. (05 Mar 2000) |
| Guldberg-Waage law | <chemistry> This law states that the rate of a given chemical reaction is proportional to concentration of the reactants. (09 Oct 1997) |
| Pfluger's law | A given segment of a nerve is irritated by the development of catelectrotonus and the disappearance of anelectrotonus, but the reverse does not hold; i.e., excitation occurs at the cathode when the circuit is closed and at the anode when it is opened. Synonym: Pfluger's law. (05 Mar 2000) |
| Roscoe-Bunsen law | In two photochemical reactions, e.g., the darkening of a photographic plate or film, if the product of the intensity of illumination and the time of exposure are equal, the quantities of chemical material undergoing change will be equal; the retina for short periods of exposure obeys this law. Synonym: reciprocity law, Roscoe-Bunsen law. (05 Mar 2000) |
| Rosenbach's law | In affections of the nerve trunks or nerve centres, paralysis of the flexor muscles appears later than that of the extensors, in cases of abnormal stimulation of organs with rhythmical functional periodicity, there is often a grouping of the individual acts with corresponding lengthening of the pauses, in such a way that the proportion of total rest and activity remains nearly the same. (05 Mar 2000) |
| wallerian law | After section of the posterior root of a spinal nerve between the root ganglion and the spinal cord, the central portion degenerates; after division of the anterior root, the peripheral portion degenerates; the trophic centre of the posterior root is therefore the ganglion, that of the anterior root the spinal cord. (05 Mar 2000) |
| Weber-Fechner law | The intensity of a sensation varies by a series of equal increments (arithmetically) as the strength of the stimulus is increased geometrically; if a series of stimuli is applied and so adjusted in strength that each stimulus causes a just perceptible change in intensity of the sensation, then the strength of each stimulus differs from the preceding one by a constant fraction; thus, if a just perceptible change in a visual sensation is produced by the addition of 1 candle to an original illumination of 100 candles, 10 candles will be required to produce any change in sensation when the original illumination was one of 1000 candles. Synonym: Fechner-Weber law, Weber's law. (05 Mar 2000) |
| Weber's law | The intensity of a sensation varies by a series of equal increments (arithmetically) as the strength of the stimulus is increased geometrically; if a series of stimuli is applied and so adjusted in strength that each stimulus causes a just perceptible change in intensity of the sensation, then the strength of each stimulus differs from the preceding one by a constant fraction; thus, if a just perceptible change in a visual sensation is produced by the addition of 1 candle to an original illumination of 100 candles, 10 candles will be required to produce any change in sensation when the original illumination was one of 1000 candles. Synonym: Fechner-Weber law, Weber's law. (05 Mar 2000) |
| Weigert's law | The loss or destruction of a part or element in the organic world is likely to result in compensatory replacement and overproduction of tissue during the process of regeneration or repair (or both), as in the formation of callus when a fractured bone heals. Synonym: overproduction theory. (05 Mar 2000) |
| Wilder's law of initial value | The direction of response of a body function to any agent depends to a large degree on the initial level of that function. Synonym: law of initial value. (05 Mar 2000) |
| Williston's law | As the vertebrate scale is ascended, the number of bones in the skull is reduced. (05 Mar 2000) |
| Plateau-Talbot law | When successive light stimuli follow each other sufficiently rapidly to become fused, their apparent brightness is diminished. (05 Mar 2000) |