ON REFLEXES IN THE SYMPATHETIC SYSTEM 223 



afférent impulses from almost any point of the body, The above réflexes 

 from the central nervous System are in nearly alL cases bilatéral. 



In view of the ease with which sensory impulses cause dilation of the 

 pupil, contraction of blood vessel and accélération of the heart, I do not 

 think that curari which was used by François Franck, is adopted for this 

 particular experiment. It prevents the head and body movements which 

 serve to warn the expérimenter that afférent impulses are being set up. 



In ail but one of the experiments mentioned in the table above, I stimu- 

 lated also the central end of the accelerator nerve. In no case did the stimu- 

 lation produce any effect on any of the structures of the head. 



I do not then think that normally either a reflex or a pseudo-reflex takes 

 place by way of the annulus of Vieussens, the ganglion stellatum, and the 

 cervical sympathetic. 



In two experiments I obtained some effect on the niçtitating membrane 

 and eyelids. Thèse were the 3'^ and ^^^ in order, the four experiments made 

 later hâve ail given négative results. In one of thèse experiments (exp. 8) the 

 cervical rami of the ganglion stellatum were uncut, — the cervical rami 

 contain no afférent fibres — in the other, the ganglion was isolated, and ail 

 ifs connections eut except the limb of the annulus. I accept then, though 

 not with absolute confidence, the view that an effect may occasionally be 

 produced by way of the ganglion stellatum and the cervical sympathetic on 

 stimulating the central end of one limb of the annulus of Vieussens, and 

 pass on to consider the mechanism by which the action is brought about. 



The results of the application of nicotine show I think that the action 

 does not involve the nerve-cells of the ganglion stellatum. After the injec- 

 tion of nicotine, stimulation of the sympathetic chain between any two 

 gangiia does not give rise to excitation of the nerve-cells of the ganglion. 

 Hence, either (1) there are no afférent fibres in the sympathetic chain which 

 can give rise to a reflex, and in that case it is most unlikely there are any 

 in the annulus of Yieussens, or (2) thèse afférent fibres are paralysed by 

 nicotine. In both experiments 7 and 8, nicotine 0.5 per cent was applied to 

 the ganglion stellatum, and this had no effect upon the movement of the 

 niçtitating membrane caused by stimulating the central end of the ventral 

 limb of the annulus of Vieussens. This effect was produced as before, 

 although the normal effect on the hairs of the back and on the foot caused 

 by stimulating the sympathetic below the ganglion stellatum was no larger 

 obtained. On the other hand application of nicotine to the superior cervical 

 ganglion at once stopped the " reflex ". The foUowing abstract from one 

 of the experiments will perhaps make this point clearer : 



Cat. A. C. E. mixture. Tie the ventral limb of the lefl annulus of Vieussens 

 close to the inferior cervical ganglion. Cut the rami of the first three thoracic 



