



TENTH AND RLE VENTH NER VES. 663 



decidedly in favour of vaso-dilators in the fifth, but in the meantime we 

 may regard the view as still requiring proof. 



Tenth and eleventh nerves. The autonomic fibres of the tenth 

 and eleventh nerves are in their central origin homologous with the 

 autonomic fibres of the ninth and seventh, which we have considered 

 above. The fibres run in the vagus. The vagus l supplies motor fibres 

 to the oesophagus, stomach, and probably the rest of the gut, as far as 

 the descending colon, and inhibitory fibres to the heart ; it sends also 

 motor fibres to the unstriated muscle of the lungs, and, according to 

 recent observations, secretory fibres to the gastric glands and to the 

 pancreas. There is evidence also that the vagus contains inhibitory as 

 well as motor fibres for the gut, but this is not admitted by all observers. 



The presence in the vagus of motor fibres for the spleen is denied. 2 Accord- 

 ing to Schiff, the vagus contains accelerator fibres for the heart, and Eutherford 

 found (1869) that stimulation of the vagus caused acceleration of the heart 

 after atropin had been injected. Brown-Sequard (1854) and Porter (1896) 

 state that stimulation of the vagus in the lower cervical region causes contrac- 

 tion of the coronary arteries. These effects on the heart and blood vessels 

 may possibly be due to fibres running to the vagus from the superior cervical 

 ganglion. 



So far as the experiments have gone, all the autonomic fibres of the 

 vagus arise from the medulla, and none from the cervical spinal cord. 

 The oesophageal fibres arise from the roots of the tenth nerve, the 

 cardiac inhibitory fibres arise from the medullary roots of the eleventh 

 nerve, and, according to Kreidl, from the uppermost of these. 3 Accord- 

 ing to Vulpian, 4 both the tenth and the eleventh nerves give motor 

 fibres to the stomach. 



The efferent autonomic nerve fibres of the tenth and eleventh are apparently 

 not connected with either the cells of the jugular ganglion or of the ganglion 

 of the trunk of the vagus. 



It was found by Waller 5 that, when the vagus was cut between the jugular 

 ganglion and the ganglion of the trunk, and time left for degeneration, 

 stimulation of the vagus in the neck had no effect upon the " lungs, larynx, 

 etc." He concluded that the motor fibres of the vagus were not connected 

 with the ganglion trunci vagi. 



Gaskell 6 found in the crocodile and alligator that, after degenerative 

 section of the vagus in the neck, stimulation of the nerve peripherally of a 

 ganglion, which occurs at the entrance of the vagus into the thorax, caused 

 contraction of the lower part of the oesophagus and of the stomach, but not 

 inhibition, of the heart. As he considered that this ganglion was homologous 

 with the ganglion trunci vagi of mammals, he inferred that the ganglion trunci 

 vagi was on the course of the efferent fibres to the oesophagus and stomach. 



Gad and Joseph 7 repeated Waller's experiment ; they found that the 

 motor fibres for the oesophagus were not connected with the ganglion trunci 



1 For details and references, cf. the sections of this Text-Book dealing with the several 

 organs or tissues. 



2 Cf. Schiifer and Moore, Journ. PhysioL, Cambridge and London, 1896, vol. xx. p. 1. 



3 Kreidl, Sitzunysb. d. k. Akad. d. Wissensch., math.-naturw. CL, Wien, 1897, Bd. 

 cvi. Abth. 3, S. 197. References to earlier observations on the functions of the several 

 roots will be found in this paper. 



4 Compt. rend. Acad. d. sc., Paris, 1885, tome ci. p. 851. 



5 Ibid., 1852, tome xxxiv. p. 582. 



6 Journ. PhysioL, Cambridge and London, 1886, vol. vii. p. 20. 



7 Arch.f. PhysioL, Leipzig, 1889, S. 209. 



