1890.] 



The Superior Cervical Ganglion. 



389 



pathetic was stimulated several days after section of the facial nerve. 

 He attributed it to a contraction of the orbicularis palpebrarum. It 

 is possible that the sympathetic has nerve fibres stimulation of which 

 causes closure of the eye, as well as fibres stimulation of which causes 

 opening of the eye, and that the nerve cells in the superior cervical 

 ganglion connected with the former are less easily paralysed by 

 nicotin ; but there is no decisive evidence of this, and the closure 

 obtained may be explained in other ways. 



Summary. 



Generally speaking, stimulation of the cervical sympathetic in the 

 dog with minimal effective shocks causes pallor in the lips and gums ; 

 with weak to moderately strong shocks, primary pallor followed by 

 flushing ; with strong shocks, as shown by Dastre and Morat r 

 primary flashing, but the extent and duration of the primary effect 

 and of the secondary effect, if there is any, varies in different dogs. 



In the rabbit and cat, stimulation of the cervical sympathetic 

 always causes, as" shown by Bochefontaine and Yulpian, primary 

 pallor in the lips and gums, and the after-flush is not great. The 

 pallor we find is bilateral ; the degree of the pallor on the opposite 

 side to that stimulated varies in individual cases, and can be seen on 

 the tongue, as well as on the lips and gums. 



On injecting nicotin into a vein, certain of the normally occurring 

 effects of stimulating the cervical sympathetic cease before the others, 

 i.e., since all the effects can still be produced by stimulating the fibres 

 running from the superior cervical ganglion, the nerve cells in the 

 ganglion, which are connected with different classes of nerve fibres,, 

 are paralysed with different degrees of ease by nicotin. 



Arranging the various effects in the order of ease of paralysis, w& 

 have : — 



Babbit. 



(1.) Withdrawal of the nictitating membrane. 

 (2.) Opening of eye. 

 (3.) Dilation of pupil. 

 j(4.) Constriction of blood-vessels of conjunctiva. 

 <-(5.) Constriction of blood-vessels of lips and gums, 

 {(6.) Constriction of blood-ves-sels of ear. 



In one or two cases, no difference in the ease of paralysis between* 

 the bracketed actions has been observed. 



Gat. 



(1.) Secretion from sub-maxillary gland, 

 (2.) Opening of eye. 

 (3.) Dilation of pupil. 



(4.) Constriction of blood-vessels of conjunctiva, 

 (5.) Constriction of blood-vessels of mouth. 



2 F % 



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(1) 



