1890.] 



The Superior Cervical Ganglion. 



387 



paralysed less readily than the other effects of the sympathetic on the 

 eye ; in some experiments we have found a very considerable, in others 

 a very slight, difference. Experiment V is an instance of: the latter 

 case. 



Experiment VI. 



Cat (C. p. 30). Chloroform. Eight sympathetic ligatured and cut. 



3.25. Inject into crural vein 4 mgm. nicotin. 



3.38. Stim. sy., c = 9 ; all the usual effects produced. 



3.44. Inject 4 mgm. nicotin. 



3.51. Stim. sy. : all the usual effects produced. 



3.55. Inject 4 mgm. nicotin. 



3.59. Stim. sy., 10 sees., c = 9 ; nictitating membrane withdrawn a little, no other 

 effect. 



4.0J. Stim. sy.. 10 sees., c = 8; nictitating membrane slowly drawn back, no 

 other effect. 



4.1^. Stim. sy., 5 sees., c = 8 ; same effect, and pupil slightly dilated. 



4.2. Stim. sy., 5 sees., c = 8 ; as before, and slight contraction of lower eyelid 



and mouth observed. 

 4.4. Stim. sy., 60 sees., c = 8 ; little, if any, immediate effect on tongue, but a 



slight after-flush. 



4.6. Stim. sy., 60 sees., c = 8; mouth chiefly observed, a little paling of tongue 

 and lips at first, changing to slight flushing at end of stimulation; pupil, 

 as before, shows slight dilation only. 



In this experiment, the dilation of the pupil was noticed before the 

 opening of the eye, but, in some other cases, we have not been able 

 to satisfy ourselves that this occurred. And it is possible that the 

 position of the eyelids, whether nearly closed, or half-open, as they 

 usually are after nicotin, influences the result. Similarly, we have 

 not been able to assure ourselves at what time, in relation to the dila- 

 tion of the pupil, a paling of the conjunctiva, and a paling of the 

 mucous membrane of the mouth, occurs. We are inclined to place 

 them in order of ease of paralysis, as follows : paling of mouth, 

 paling of conjunctiva, opening of eyelids, dilation of pupil. We have 

 not made a comparison between the ease of paralysis of the sym- 

 pathetic effect upon the withdrawal of the nictitating membrane and 

 the constriction of the vessels of the ear. 



The Dog. — When nicotin, even in large amount, is injected into a 

 vein in the dog, there is a rapid recovery of the effect of stimulating 

 the cervical sympathetic* as regards the constriction of the small 

 arteries of the salivary glands, the dilation of the pupil, and the 

 secretion of saliva. We have generally observed a slight difference 

 in the time of recovery of these three effects, in the order in which 

 they are mentioned above, but there are special difficulties in the way 

 of determining the exact time when stimulation of the nerve begins 



, j * Cf. Langley, ' Journ. of Physiol.,' vol. 11, 1889, p. 123. 

 VOL. XLVI1. 2 F 



