NERVE CELL CONNECTLON OF NERVE FLBRES. 621 



The origin of the other fibres of the cervical sympathetic are 

 omitted, as they have not been studied in sufficient detail. " Good," 

 " moderate," and " slight " in the table indicate the relative effects pro- 

 duced by the several spinal nerves. 



It must be remarked that there is some evidence 1 that the vaso- 

 motor fibres for the iris have the same origin as the fibres for the 

 dilatator pupillpe, and thus a different origin from that of the vasomotor 

 fibres for the conjunctiva and ear, but not many experiments have been 

 made on the point. 



The earliest observations on the origin from the spinal cord of the cervical 

 sympathetic fibres were made by Budge and Waller in 1851, with regard to 

 the dilator fibres for the pupil. They found dilatation of the pupil in the 

 rabbit, on stimulating the second thoracic nerve. The results obtained by 

 various observers are conflicting. The account I have given above is based 

 upon my own experiments ; in many respects it agrees with that given by 

 some one or other of the earliest observers ; thus the account of the origin 

 of the fibres for the dilatator pupillse is essentially the same as that given by 

 Bernard. It may be mentioned that a considerable number of observers state 

 that fibres run to the cervical sympathetic from the lower cervical nerves. I 

 append below a list of papers for reference. 2 



Nerve cell connection of the nerve fibres.— The nerve fibres which 

 run from the spinal cord to the cervical sympathetic and to the superior 

 cervical ganglion all end in connection with the nerve cells of this 

 ganglion, 3 for if the ganglion in the cat or rabbit be brushed over with 

 05 to 1 per cent, nicotin, in amount insufficient to appreciably affect 

 the conductivity of nerve fibres, stimulation of the cervical sympathetic 

 will have no effect. 



The absence of effects must be due to a loss of conductivity some- 

 where in the ganglion ; and in accordance with what we know generally 

 of the action of alkaloids, as well as in accordance with the results of 

 recent histological inquiry, we may fairly conclude that the break of con- 

 ductivity occurs in the terminations of the sympathetic fibres around the 

 cells of the superior cervical ganglion. In other words, we may say that 

 the absence of effect on stimulating the cervical sympathetic is due to 

 the fact that all its fibres form nerve-endings in the ganglion, and that 



1 Langley and Anderson, Joum. Physiol., Cambridge and London, 1892, vol. xiii. p. 577. 



2 Pupillo-Dilator Fibkes. — Budge and Waller, C'ompt. rend. Acad. d. sc, Paris, 1851, 

 tome xxxiii. p. 370 ; Budge, ibid., 1852, tome xxxv. p. 255 ; Arch. f. physiol. Heilk., Tubin- 

 gen, 1852, S. 773; "Ueber d. Bewegung der Iris," Braunschweig, 1855, S. Ill ; CI. Bernard, 

 Joum. de la physiol. dc Vhomme, Paris, 1862, tome v. p. 383 ; Salkowski, Ztschr. f. rat. 

 Med., 1867, Bd. xxix. S. 167 ; Francois-Franek, Trav. du Lab. dc Marcy, 1880, tome iv. 

 p. 26 ; Ferrier, Proc. Roy. Soc. London, 1883, vol. xxxv. p. 229; Nawrocki u. Przybylski, 

 Arch.f. d. rjes. Physiol., Bonn, 1891, Bd. i. S. 262 ; Langley, Phil. Trans., London, 1892, 

 vol. clxxxiii. p. 85; Joum. Physiol., Cambridge and London, 1897, vol. xxii. p. 217; 

 Sherrington, ibid., 1892, vol. xiii. p. 702. 



Vasomotor Fibres. — Budge, C'ompt. rend. Acad. d. sc, Paris, 1853, tome xxxvi. p. 

 377 ; CI. Bernard, ibid., 1862, tome lv. p. 381 ; Salkowski, Ztschr. f. rat. Med., 1867, 

 Bd. xxix. S. 167; Dastre and Morat, C'ompt. rend. Actid. <t. sc, Paris, 12th Feb. 1883; 

 " Systeme nerveux vaso-moteur," Paris, 1884, p. 132; Langley, Phil. Trans., London, 

 1892, vol. clxxxiii. p. 85 ; Joum. Physiol., Cambridge and London, 1897, vol. xxii. 

 p. 217. 



Pilo-Motor Fibres. — Langley and Sherrington, Jour n. Pin/sin/., Cambridge and Lon- 

 don, 1891, vol. xii. p. 166; Langley, ibid., 1893, vol. xv. p. 213 ; 1897, vol. xxii. p. 217. 



Secketory Fibres.— Langley, "Phil. Trans., London, 1892, vol. clxxxiii. p. 104. 



3 Langley and Dickinson, Proc Roy. Soc. London, 1889, vol. xlvi. p. 424 ; ibid., 1890, 

 vol. xlvii. p. 379 ; Langley, Joum. Physiol., Cambridge and London, vol. xi. p. 146. 



