18D0.] 



The Superior Cervical Ganglion. 



383 



the anterior part of the lower lip the pallor is nearly equal on the two 

 sides, in the upper lip the paling on the opposite side to that stimulated 

 is distinct, though slight. 

 12.30. Cut right sympathetic and both vagi at the level of the upper part of the 

 larynx. 



Stim. sy., e = 9, for 20 sees. Bilateral pallor in upper and lower lip as 

 before. 



We may mention that, notwithstanding the difference in the dog 

 on the one hand, and the cat and rabbit on the other, in the effect of 

 stimulating the sympathetic on the bucco-facial region, a small dose 

 of nicotin causes in each case a primary flushing in the region ; in the 

 dog the flushing is most intense, in the cat and rabbit it is compara- 

 tively slight, and may be very brief. Of this we shall have more to 

 say in a later paper on the general action of nicotin. 



Having thus given the effects which may be expected to follow 

 stimulation of the sympathetic in the neck, we may now proceed to 

 consider the order in which they cease on injecting into the blood- 

 vessels small doses" of nicotin. Our experiments have been made upon 

 the rabbit, cat, and dog. As a rule, in any one experiment, a few 

 only of the effects can be accurately observed. Thus, in order to 

 observe with certainty a slight dilation of the pupil, it may be neces- 

 sary to pull back the eyelids, in which case a slight movement of the 

 eyelids, if such were caused by the stimulation, might escape observa- 

 tion. It has appeared to us that the effect of stimulating the 

 sympathetic on the movements of the eyelids, the eye, and especiallv 

 on the nictitating membrane, diminishes with the amount of the anaes- 

 thetic given. At any rate, in the rabbit and cat we have occasionally 

 observed so little effect on the nictitating membrane to be caused by 

 stimulating the sympathetic, that no certain conclusion could be 

 drawn from the absence of such effect after giving nicotin. 



It is necessary, then, to note carefully to what extent the various 

 effects which may be produced by stimulating the sympathetic are in 

 fact produced, immediately before the introduction of nicotin. 



In nearly all cases the sympathetic in the neck was ligatured and 

 cut. This was done, in the first place, to avoid reflex action, and, 

 secondly, in the hope that, since section of the sympathetic commonly 

 produces the opposite effects of stimulation, the effects of stimulation 

 might thereby become more marked. It has often been noticed that 

 section of the sympathetic produces a transient slight effect only, or 

 even none ; this was the case in most of our experiments, so that at 

 the time of injecting nicotin, the ears and pupils on the two sides were 

 alike, occasionally the ear being flushed but the pupil not contracted, 

 or the pupil being a little contracted but the ear not flushed, on the 

 cut side. 



We have mentioned above that we have sometimes made observa- 



