THE SPINAL CORD. 



By C. S. Sherrington. 



Contexts : — Reflex Action, p. 783 — The Way In, p. 787 — Recurrent Sensitivity, 

 p. 788— The Way Out, p. 793— Relation of Afferent to Efferent Root Cell, 

 ]). 797 — Reflex tonus, p. 799 — Regeneration of Afferent Roots, p. 804 — 

 Functional Anatomy of Mediate Spinal Cell-Systems, p. 804 — The Spinal 

 Grey Matter, p. 810 — Reflex Capacity of Fragments of the Cord, p. 811 — 

 The Spinal Animal, p. 817— Rules of Spread in "Short" Reflexes, p. 820 

 —In Long Reflexes, p. 823 — Influence of the Quality of the Stimulus, 

 p. 825— Summation of Stimuli, p. 828 — Intensity of the Stimulus, p. 828 — 

 Chai'acter of the Muscular Response, p. 830 — Influence of the Locus of the 

 Stimulus, p. 832— "Local Sign" and Spinal Reflexes, p. 832 — Fatality of 

 Spinal Reflexes, p. 834 — Influence of Condition of the Central Organ itself ; 

 Vascular Condition, p. 835 — Drugs, p. 837 — Influence of Associated Parts of 

 the Central Organ ; Inhibition and " Bahnung," p. 837 — Co-ordinate Character 

 of the Movements, p. 843 — Phasic Variation in Reflex Activity, p. 844 — 

 Autotomy, p. 845 — Spinal "Shock," p. 845 — Difference between Skeletal and 

 Visceral Musculature in regard to Shock, p. 847 — Spinal Visceral Reflexes, 

 p. 849 — Urinary Bladder, p. 849 — Defalcation, p. 850 — Sexual Spinal Reflexes, 

 p. 851 — Other Visceral Reflexes, p. 853 —Reflexes affecting the Vascular Mus- 

 culature, p. 854 — Significance of Spinal Reflexes, p. 856 — Spino-cerebral and 

 Cerebro-Spinal Reactions, p. 860 — Conduction in the Cord, p. 861 — Spinal 

 Traumatic Hyperajsthesia, p. 867 — Tonic Functions of the Cord, p. 868 — 

 Automatism, p. 869 — "Knee-Jerk" and Allied Phenomena, p. 870 — Trophic 

 Functions of the Cord, p. 875— Regeneration of the Spinal Cord, p. 878. 



Keflex Action. 



Spontaneously arising conversions of internal into external energy, such 

 as characterise the life of certain cells, for instance those of cardiac 

 muscle, are not apparent in the life of spinal cells. All purely spinal 

 reactions seem reactions to environmental change. They are reflex in 

 the sense that the environment is causally related to them, and that 

 to the environment they return again. The initiation of some is less 

 directly and demonstrably traceable from the environment than that 

 of others. The former are by a convenient usage often termed " spon- 

 taneous." The latter or obviously reflex comprise for the most part 

 the relatively simpler. The distinctions drawn between reflex and 

 spontaneous reactions naturally alter from time to time. The tendency 

 with increasing knowledge of physical and chemical agents has been 

 for an increasing number of reactions to be included as reflex. 



Among the properties of living matter (bioplasm), those which by 

 their high development in the nervous system may be said to charac- 

 terise the physiological qualities of that system, are excitability to 

 certain kinds of stimuli, spatial transmission of the excited state, and 

 ability to control the liberation of energy in tissues adjoint to them- 



