LAW 



330 



LAW 



Neuron. L., Flatau's, "law of the eccentric situa- 

 tion of long tracts." The greater the length of the 

 fibers of the spinal cord, the nearer to the periphery- 

 are they situated. L., Freund's. See under Tumor. 

 L., Gerhardt-Semon's, certain central or peripheral 

 lesions of the recurrent laryngeal nerve cause the vocal 

 cord to assume a position midway between adduction 

 and abduction, the lesion of the nerve being insufficient 

 to destroy it and to provoke a complete paralysis of 

 the vocal cord (cadaveric position). L., Giraud- 

 Teulon's, binocular retinal images are localized at 

 the point of intersection of the primary and secondary 

 axes of projection. L., Goldscheider-Marinesco's. 

 See under Neuron. L., v. Gudden's, the proximal 

 end of a divided nerve undergoes cellulipetal degen- 

 eration. L., Gullstrand's, when the corneal reflex 

 from either of the eyes of the patient, who is made to 

 turn the head while fixing some distant object, moves 

 in the direction in which the head is turning, it moves 

 toward the weaker muscle. L., Gull-Toynbee's. 

 See under Otitis. L., Hering's, the distinctness or 

 purity of any sensation or conception depends upon the 

 proportion existing between their intensity and the sum 

 total of the intensities of all simultaneous sensations 

 and conceptions. L., Jackson's (Hughlings), that 

 neural functions latest developed are earliest over- 

 thrown. L., Kahler's, L., Kahler-Singer's, the 

 ascending branches of the posterior spinal nerve- 

 roots, after entering the cord pass successively from 

 the root-zone toward the mesial plane. L., Koch's, 

 or Postulates, the specificity of a microorganism is 

 conclusively demonstrated when the following condi- 

 tions are fulfilled: (i) The microorganism must be 

 present in all cases of the disease ; (2) it must be culti- 

 vated in pure culture ; (3) its inoculation must produce 

 the disease in susceptible animals; (4) from such ani- 

 mals it must be obtained and again cultivated in pure 

 culture. L., Kolk's (Schroeder van der), a spinal 

 nerve endows the muscles with motion through its 

 motor branches and the parts moved with sensation 

 'through its sensory branches. L., Kuester's. See 

 under Tumor. L., Lancereaux's. See under Throm- 

 bosis. L., Lasegue's, superficial lesions or simple 

 functional troubles of an organ increase the reflexes, 

 while more or less pronounced organic lesions suppress 

 them. L., Leopold's, insertion of the placenta into 

 the posterior uterine wall pushes the fallopian tubes 

 forward, so that they assume a convergent direction on 

 the anterior wall ; insertion into the anterior wall causes 

 them to turn backward and parallel to the longitudinal 

 axis of the recumbent woman. L., Magendie's. See 

 Z., Bell's (IIlus. Diet.). L., Marey's, a high-tension 

 pulse is a slow pulse. L., Mendel's [a German 

 monk, 1865], that a first cross will result in offspring 

 resembling one or the other parent, and possessing in 

 an undeveloped form, termed "recessive," the attri- 

 butes of the other. The second cross will result in fixed 

 types posse-sing respectively the character of one 

 parent, "dominant," and of both parents in vary- 

 ing degrees. L., Meyer's, mature and normal bone 

 possesses a definite internal structure, which in every 

 part represents the lines of greatest pressure or traction, 

 and is so MTanged as to afford the greatest resistance 

 with the smallest amount of material. L., Miiller's, 

 (1) the tissue of which a tumor is composed has its type 

 in the tissues of the animal body, either in the adult or 

 the embryonic condition ; (2) "law of isolated conduc- 

 tion." The nervous impulse, or "wave of change," 

 passing through a neuron is not communicated to other 

 neurons, even when these lie close alongside of it, 

 except at the terminals. L., Neumann's, in bodies 

 of analogous composition the specific heats are inversely 



as the stoichiometric quantities, or, what is the same, 

 stoichiometric quantities of bodies of analogous chemical 

 composition have the same capacity for heat. L., 

 Nysten's, rigor mortis begins in the muscles of masti- 

 cation, extends to the facial and neck muscles, then to 

 the trunk and arms, and finally to the lower extremities. 

 L., Ollier's, when two bones are parallel and joined 

 at their extremities by ligaments, arrest of growth in 

 one of them entails developmental troubles in the other. 

 L., Pajot's. See Tajot's Law (Illus. Diet.). L., 

 Parallel. See Z., Tec/itier's (Illus. Diet.). L., 

 Periodic, the properties of the elements are periodic 

 functions of their atomic weights. L., Peter's, athero- 

 matous changes in blood-vessels are most apt to occur 

 where there are angles and projections. L., Pfluger's, 

 of Contraction, galvanic stimulation of a nerve causes 

 muscular contraction, which varies uniformly according 

 as the kathode or the anode is applied, or as the cur- 

 rent is closed or opened. Certain deviations from this 

 law constitute the reaction of degeneration. The law 

 may be briefly stated as follows : 



C, contraction ; Te, tetanic contraction. 



L., Pfluger's, of Reflex Action, (1) if stimulation 

 of a sensory nerve be followed by a unilateral reflex 

 movement, the latter always occurs on the side to which 

 the sensory nerve belongs. (2) If the stimulus received 

 by a sensory nerve extend to motor nerves of the op- 

 posite side, contraction occurs only in the correspond- 

 ing muscles. (3) If the contraction be unequal on 

 the two sides, the stronger contraction always takes 

 place on the side which is stimulated. (4) If the 

 reflex excitement extend to other motor nerves, the 

 direction of the impulse from the sensory to the motor 

 nerve is from before backward in the brain ami from 

 below upward in the spinal cord — i. e., always in the 

 direction of the oblongata. L.> Poiseuille's, the 

 rapidity of the current in capillary tubes is proportional 

 to the square of their diameter. L., Profeta's, healthy 

 offspring from syphilitic parents are immune to syphilis. 

 L., Ritter's, of Contraction, stimulation of a nerve 

 occurs both at the moment of closing and of opening 

 of the electric current. L., Rommelaere's, constant 

 diminution of the nitrogen in the urine in cases of car- 

 cinoma. L., Rosenbach-Semon's. See Z., 

 Semon's. L., Schroeder van der Kolk's. See Z., 

 Kolk' s. L., Semon's, in progressive organic lesions 

 of the motor laryngeal nerves the cricoarytenoidei 

 postici — the abductors of the vocal cords — are the fust. 

 and sometimes the only, muscles affected. L., Sher- 

 rington's, the peripheral branches of the spinal nerve- 

 roots — anterior and posterior — form anastomoses in sue) 

 a manner as to supply any given region of the integu- 

 ment with the branches of three roots — a middle one 

 and the ones next above and below. L.s, Snell's, 

 L.S of Sines, the two laws which govern single 

 refraction: (1) The sine of the incident angle bears 

 a fixed ratio to the sine of the angle of refraction tor 

 the same two media, the ratio varying with different 

 media. (2) The incident and the refracted ray are in 

 the same plane, which is perpendicular to the surface 

 separating the two media. L., Talbot's, L., Tal- 

 bot-Plateau's, when the visual stimuli proceeding 

 from a revolving disc are completely fused, and the 

 sensation is uniform, the intensity is the same as that 



