ON THE ORGANIC FUNCTIONS. 867 



the free communication between one ganglion-cell and another, which is 

 established through the vesicular substance of a ganglion, so that the whole 

 force of ordinary impressions on the nerve-fibres is lost in diffusion among 

 the rest of their contents. The same principle seems to apply to the motor 

 fibres; for there are cases which show that when fibres obviously belonging 

 to Cerebro-spiual nerves pass through Sympathetic ganglia, they do not so 

 rapidly or so surely transmit motor impulses, as when they have no such 

 relation to ganglia. 1 



715. The effects of section and of galvanization of the cut extremities of 

 the sympathetic nerve in the neck, have been carefully investigated by Ber- 

 nard, Waller, Browu-Sequard, 2 and others. On dividing the nerve, the 

 bloodvessels of that side of the head dilate, and with the freer current of 

 blood which is then established through the capillaries, an increase of the 

 vital properties of all the tissues on the same side of the head is associated. 

 Thus the sensibility of the retina for light appears to be augmented, whence 

 follow contraction of the pupil, retraction of the globe of the eye, partial 

 closure of the eyelid, and projection of the membrana nictitans (where pres- 

 ent ) with increased flow of tears. The temperature and sensibility of the 

 skin, and the cutaneous secretions, are also much increased, the tempera- 

 ture in some of Dr. Waller's experiments 3 rising as much as 18 Fahr., and 

 the skin in some of M. Bernard's being bathed with perspiration. The color 

 of the venous blood assumes a brighter hue, and its coagulation is more 

 rapid. The muscles respond more readily to weak, and more energetically 

 to strong stimuli, and retain their irritability longer; rigor mortis conse- 

 quently sets iu more slowly and endures for a longer period ; hypertrophy 

 of the facial bones has been noticed by Schiff, and Benedikt 4 has observed a 

 similar result to occur in certain muscles; whilst it further appears from 

 Suellen's researches 5 that even the inflammatory and reparative processes, as 

 the effusion of serum, the formation of pus, the absorption of effused blood, 

 and the cicatrization of wounds, take place with very much greater energy 

 and rapidity. On the contrary, when the upper cut extremity of the nerve 

 is galvanized, all these phenomena are reversed; for now, as a consequence 

 of the contraction of the bloodvessels and the diminished supply of blood 

 which ensues, the vital properties of the tissues are diminished, the pupil 

 dilates, the eyelid is widely opened, the temperature and sensibility of the 

 parts decrease, the contractile power of the muscles is less strongly marked, 

 their normal galvanic current is feeble, and cadaveric rigidity sets in quickly 

 and soon passes off, putrefaction immediately supervening. The effects pro- 

 duced by section of the Sympathetic in the neck are much more strongly 

 marked when the cervical ganglia are destroyed, and Bernard 6 states that 

 closely similar results follow section of the Sympathetic nerves distributed 

 to the vessels of the extremities. In these latter experiments he found that 

 division of the roots of the spinal nerves within the spinal canal, though 

 abolishing sensation and motion in the limb beyond, yet produced no effect 

 upon .its temperature; whilst if after such section the sciatic or brachial 

 nerves were divided, an immediate exaltation of temperature ensued ; clearly 

 showing that the nerve-fibres devoted to the conduction of sensory and motor 

 impulses issuing from the spinal cord had been joined by a third set of fibres, 



1 See Messrs. Kirkes and Paget's Handbook of Physiology, p. 420. 



2 See Lectures on the Central Nervous System, 1800, lectures ix and x. 



3 Comptes Eendus, 1853. 



4 Electro-therapie, Wien, 1868, p 88. 



5 Henle and Meissner's Bericht, 18- r >7, p. 373. 



6 See Gazette Hebdomad., Aout, 1862 ; Comptes Kendus, vol. ii, 1862 ; and Journal 

 de la "Physiologic, vol. v. 



