THE HISTORICAL DEVELOPMENT OF NEUROPHYSIOLOGY 



39 



(for the vagus) and Hering (216) (for black-white 

 sensations of the visual sense), by Vervvorn (2 1 7) (in 

 his Biogenhvpothese). The hypothesis did not survive 

 for long. As Forbes (218) said in his critique, "To 

 assume that increase of anabolism necessarily implies 

 decrease of catabolism, is to suppose that increasing a 

 man's salary ensures decrease of his expenditure." A 

 theory of immobilization of ion transfer during inhi- 

 l)ition was propo.sed by Macdonald (219) in 1905, at 

 a time when the release of potassium from injured 

 nerves was receiving considerable attention. 



With the discovery of the refractory period in nerve 

 [by Gotch and Burch (220) in 1889] there was some 

 tendency to regard block of conduction due to excita- 

 tory impulses arriving during refractoriness caused by 

 preceding excitation to be the mechanism of inhibi- 

 tion. This is now recognized as a misuse of the term, 

 and in fact Sherrington's demonstration that after 

 discharge persisting after cessation of excitation could 

 be cut short by inhibitory nerve action was an early 

 salutory corrective. 



In the course of researches on the inexhaustibility 

 of nerve, a subject which engrossed the early electro- 

 physiologists, Wedensky (221) found that a rapid 

 series of strong stimuli would fail to produce more 

 than a single twitch if the transmission from nerve to 

 muscle were blocked either by fatigue at the end plate 

 or by artificially impairing a section of the nerve by 

 narcosis. If however the frequency or the strength of 

 the tetanus were then reduced, the muscle went im- 

 mediately into tetanic contraction. Wedensky con- 

 cluded that the nerve was inexhaustible and that the 

 phenomenon was one of inhibition. This may, how- 

 ever, be regarded as a special usage of the term since 

 the effect he observed was merely a characteristic of 

 the relative refractory period of nerve and its time 

 course as related to strength of stimulus (222). 



It was Sherrington's insistence on a central site for 



216. Hering, Heinrich Ewald (1866-1948). Zur Thcorio dc 

 Vorgange in der lebendigen Substanz. Lotos g: 35, 1889; 

 translated in Brain 20: 232, 1897. 



217. Verworn, Max. Die Biogmhypothcse. Jena: Fischer, 1903. 



218. Forbes, Alexander. Reflex inhibition of skeletal muscle. 

 Quart. J. Exper. Physiol. 5: 149, 1912. 



219. Macdonald, J. S. The structure and function of nerve 

 fibres. Proc. Roy. Soc, London, ser. B 76: 322, 1905. 



220. Gotch, F. and G. J. Burch. The electrical response of 

 nerve to two stimuli. J. PhysioL 24: 410, 1899. 



221. Wedensky, Nicholai Yevgenevich (1852- 1922). Die 

 Erregung, Hemmung und Narkose. .Arch. s^es. Physiol. 

 100: I, 1903. 



222. Adrian, E. D. Wedensky inhibition in relation to the 

 "all-or-none" principle in nerve. J. PhysioL 46: 384, 1913. 



the inhibitory mechanisms of skeletal muscle that 

 emphasized the reflex nature of inhibition. The con- 

 tributions of Sherrington and his school are the basis 

 of modern ideas of the reflex at the spinal level. A 

 great number of findings (223-227) made by Sherring- 

 ton and brought together into a unifying explanatory 

 scheme included the following major observations: that 

 postural tonus of a muscle is dependent not only on 

 efferent nerves but on afferent nerves from that muscle 

 itself, the stimulus to the latter being from stretch re- 

 ceptors [the myotatic reflex (223)]; that decerebrate 

 rigidity (224) is an e.xaggerated muscle tonus in the 

 antigravity muscles — a reflex standing ["an harmo- 

 nious congerie of stretch-reflexes" (225)]; that the 

 afferent nerve from a given muscle can elicit a con- 

 traction in that muscle itself (228), without involve- 

 ment of the opposing muscles of the joint;-'' that the 

 main stimulus for the stepping reflex (229) does not 

 come from contact of the foot with ground, as might 

 be expected;-" that stimulation causing fle.xion in one 



223. LiDDELL, E. G. T. AND C. S. SHERRINGTON. ReflcXCS in 



response to stretch (myotatic reflexes). Proc. Roy. Soc, 

 London, ser. fi 96: 212, 1924. 



224. Sherrington, C. S. Cateleptoid reflexes in the monkey. 

 Proc. Roy. Soc, London, ser. B 60: 41 I, 1897. 



225. Sherrington, C. S. Problems of muscular receptivity. 

 Linacre Lecture. Mature, London 113: 732, 892, 929, 1924. 



226. Sherrington, C. S. Selected Writings of C. S. Sherrington, 

 edited by D. Denny-Brown. London: Hamish Hamilton, 

 1940. 



227. Sherrington, C. S. Note on the knee-jerk and the corre- 

 lation of action of antagonistic muscles. Proc. Roy. Soc, 

 London, ser. B 52: 556, 1892-3. 



228. Sherrington, C. S. On reciprocal innervation of an- 

 tagonistic muscle (eighth note). Proc Roy. Soc, London, ser. 

 B 76: 269, 1905. 



229. Sherrington, C. S. Flexion-reflex of the limb, crossed 

 extension-reflex, and reflex stepping and standing. J. 

 Physiol. 40: 28, 1 910. 



''* From a series of 1 4 articles by Sherrington on reciprocal 

 innervation stretching over the years from 1893 to 1909 (and 

 developed in many other of his writings), the following excerpt 

 may be quoted as one of his crucial experiments: "All the 

 nerves of the limb being severed, except those of the vasti and 

 crureus, the animal is inverted and the knee then gently but 

 fully extended by raising the foot, the thigh being held vertical. 

 The foot is then released, the anticrus falls, and in doing so is 

 seen to be suddenly checked by exciting a contraction of the 

 extensor of the knee. This contraction is different from a knee- 

 jerk, for it only slowly passes off." Sherrington, C. S. Proc. 

 Roy. Soc, London, ser. B 76: 283, 1905. 



'' ". . .in the intact animal (cat, dog), severance of all the 

 nerve trunks directly distributed to all four of the feet up to and 

 above the wrists and ankles impairs walking so little £is to make 

 it highly unlikely that the loss of receptivity of the feet destroys 

 any large factor in the reflex basis of these acts ' (235). 



