248 Further Note on the Sensory Nerves of Muscles. 



muscular, the Wallerian degeneration did clearly demonstrate a 

 result of importance. With the exception of a few minute fibres, of 

 -variable number, derived perhaps from the ciliary ganglion, all myeli- 

 nate nerve-fibres in all these eye-muscles were degenerated. There- 

 fore these eye-muscles derive the vast majority of their myelinate 

 nerve-fibres from n. oculomotorius. The sensory innervation of these 

 muscles does not therefore seem derivable from the Vth cranial pair. 

 In accord with this I found (a) that severance of both trigemini 

 •caused no obvious impairment of the movement of the eye-balls, 

 that the combined severance of both nn. trigemini, and of both optic 

 nerves even after section of the encephalic bulb did not severely 

 depress the tonus of the eye-muscles. Now we know that section of 

 the sensory spinal roots belonging to muscles does very severely 

 depress the tonus of them. 



At the same time I was struck with the long distance to which 

 many of the nerve-fibres in these muscles travel forward toward the 

 ocular tendons of the muscles. I was the more impressed with this 

 fact because direct examination proved that the region of the dis- 

 tribution of motor end-plates in these muscles is almost confined to 

 the middle portion of the fleshy mass of the muscle. Further in- 

 vestigation of the course and destination of the nerve-fibres at the 

 tendon end of the muscle revealed them (both in cat and monkey) 

 undergoing terminal subdivision, and in very numerous instances 

 passing beyond into the bundles of the tendon itself. The termina- 

 tions of many of these nerve-fibres lie within the tendons ; many 

 recurve again toward the muscular fibres, and end just at junction of 

 muscle-fibre with tendon bundle. The nerve-fibres in so terminating 

 frequently become thick — as I have described in the case of muscle- 

 spindles— with shortened internodes. 



The terminal arborisation which the nerve-fibres finally make is as 

 a rule small as compared with the end-arborisation of ordinary 

 Kuhne-Ruffini " spindles " or the Golgi " tendon-organs," but closely 

 resembles in numerous instances the form of arborisation of the 

 latter. 



In my former communication I wrote* — " The question therefore 

 arises whether the above cranial nerves (Illrd and IYth) are not in 

 reality sensori-motor." In view of the additional observations now 

 recorded I think it must be conceded that nervus oculomotorius is 

 perhaps not a merely motor nerve, but although purely " muscular" 

 may be sensori-motor. 



My observations have included also the IVth cranial pair, and 

 with like result. Investigation of the Vlth cranial pair is also in 

 progress. 



It also appears clear from the above that the absence of the dis- 

 * ' Proc. Physiol. Society,' No. 3, 1894. 



