THE SKIN AND COMMON SENSATION 971 



similar on muscles, tendons, and joints, carried out with like negative result, 

 Haller, and also Bichat in part, 1 concluded that these organs are insentient. 

 Clinical experience shows that the viscera may be freely incised in the 

 unanaesthetised patient, ligated, or pinched, without in the most evanescent or 

 slightest degree affecting the attentive consciousness. The movement of the 

 stomach and diaphragm, one against another, with large excursion and 

 considerable speed, cannot under ordinary circumstances be perceived. 



Attention cannot be induced to that direction, far less be focussed there. 

 Yet to imagine all these structures insentient were certainly mistaken, — one 

 is misled by the impotence of inadequate stimuli. The heart in its beating 

 produces normally no " feeling," but it nevertheless possesses the in some ways 

 most powerful afferent nerve in the whole body, and under certain conditions 

 evokes all engrossing pain. The voluntary muscles contain numbers of 

 afferent nerve fibres and sense organs, 2 and can produce urgent sensation. All 

 parts of the alimentary canal, under the vicissitudes of disease, give evidence of 

 capability to affect sense even with pain. Excitations of the central end of 

 the splanchnic nerve, and of many other visceral nerves, uniformly evoke 

 evidence of pain. 3 In the abdominal and thoracic sympathetic cord are 

 numbers of myelinated fibres, which are the axons of nerve cells in the spinal 

 ganglia, contributing to the afferent spinal roots. The white rami communi- 

 cantes of the sympathetic are afferent as well as efferent, for by them fibres 

 pass from the visceral nerve-chain into the spinal ganglia and roots. I 

 find a lower thoracic white ramus (tenth thoracic) in a small cat to contain 

 about 150 myelinated sensory fibres ; such fibres are therefore fairly numerous 

 in the abdominal sympathetic. 4 They vary much in size, some being amongst 

 the largest fibres in the sympathetic, but more are among the very small (12 /a 

 to 1-5 fji or less in the small cat). Some of the larger probably belong to the 

 Pacini corpuscles, numerous in the neighbourhood of the pancreas, uterus, and 

 elsewhere. The existence of abundant afferent channels from the viscera into 

 the central nervous system is therefore as definitely proved by physiological 

 research as is the existence of visceral pain demonstrated to bedside observa- 

 tion. Yet the impulses generated in the afferent nerves of the viscera, 

 although they embouch into the central nervous system (via the spinal and the 

 vagal ganglia), do not appear under ordinary circumstances to evoke conscious 

 reactions. Some authorities teach that they generate constantly "obscure 

 sensations." " If the whole of our abdominal viscera were removed, we should 

 be aware of the loss." 5 The supposition is one not of course to be tested by 

 experience. Rather than that the viscera constantly generate obscure 

 sensations, it would seem to me that some of them at least initiate inter- 

 mittently with phasic regularity sensations that are far from obscure, as well as 

 viscero-motor, secreto-motor, and other reflexes outside the pale of consciousness. 

 Sensations would seem to arise from the viscera under ordinary circumstances 

 chiefly, as might be expected, in relation to exercise of their normal 

 functions. The functional " activity " of most viscera is phasic ; sensations 

 accompanying the "activity" phase seem pleasurable, not the reverse. In 

 the prolonged phase of pause for preparation, preceding the phase of " action," 



1 Bichat did not deny the sensitivity of muscles. Scliiff. however, did so absolutely, 

 " Muskel- und Nervenphysiologie," Lahr, 1858, and so have others. 



a Sherrington, Journ. Physiol., Cambridge and London, 1893, vol. xvii. ; Brit. Med. 

 Journ., London, 1893, vol. ii. 



3 Bichat, " Anatomie generale," Paris, 1802 ; Budge and others. 



4 There appear to be none in the cervical sympathetic. Bichat remarked on the 

 insensitiveness of the superior cervical ganglion and the cervical sympathetic, "Anatomie 

 generale," Paris, 1802, tome i. p. 24. Cf. Budge and Waller; also Langley, Phil. 'J'ntus., 

 London, 1892, vol. clxxxiii. p. 117. I found all (except seven) the nerve fibres in the 

 cervical sympathetic of the monkey degenerate after section of the motor spinal roots of the 

 lowest cervical and highest six thoracic nerves. 



5 Foster, "Text-Book of Physiology," 1891, pt. 4, p. 1421. 



