384 Mr. J. N. Langley and Mr. W. L. Dickinson. [Mar. 27, 



tions on the progressive paralysis of the different sympathetic actions 

 by giving a dose insufficient to paralyse them all, and some- 

 times by giving a larger dose and noting the progressive recovery. 

 The former method is more troublesome, but brings out greater 

 differences than the latter. The order of recovery is inversely as the 

 order of primary paralysis. 



The Babbit. — As anaesthetics we have used chloral, and afterwards 

 chloroform and ether, or, more rarely, chloral and morphia. In the 

 anaesthetised animal the eyes are directed forward, and the pupils are 

 rather large ; after nicotin has been injected the eyes are directed 

 forward, and the pupils are in nearly all cases smaller than previously. 

 With regard to the relative time of paralysis of the secretory fibres 

 in the cervical sympathetic, we have made no observations in the 

 rabbit. 



The easiest comparison to make is that between one of the changes 

 which occur in the eye and the pallor of the ear. In the following 

 experiment the comparison is made between the dilation of the pupil 

 and the constriction of the central artery of the ear. The difference 

 between the ease and duration of the paralysis of these two actions, 

 though always appreciable, is nevertheless sometimes slight. The 

 experiment we quote shows, perhaps, the maximum difference which 

 we have observed. 



Experiment II. 



Rabbit (C. p. 7). Chloral given. Right sympathetic tied and cut in middle of 

 the neck. Stimulation of the sympathetic with a weakish current (c = 10) produces 

 dilation of the pupil and constriction of the arteries of the ear. 



1.59. Inject 5 mgm. nicotin. into left jugular vein. 



2.4. Stim. sy. for 20 sees., c = 10 ; no dilation of pupil, slight pallor of ear. 

 2.7. Stim. sy. for 20 sees., c = 9 ; no dilation of pupil, fair pallor of ear. 



2.10. Stim. sy. for 30 sees., c = 8 ; no dilation of pupil, slight pallor of ear. 

 2.20. Stim. sy. for 20 sees., c = 10 ; no dilation of pupil, great pallor of ear. 



2.27. Stim, sy. for 20 sees., c = 10 ; great dilation of pupil, and great pallor of 



ear. 



2.35. Inject 5 mgm. nicotin. 



2.40. Stim. sy. for 30 sees., c = 10; no dilation of pupil, slight pallor of ear. 

 3.12. Stim. sy. for 20 sees., c = 10 ; fair effect on both pupil and ear. 



3.28. Stim. sy. for 10 sees., c = 10 ; nearly maximal dilation of pupil. 



4.7. Inject 5 mgm. nicotin. 



4.8. Stim. sy. for 10 sees., c = 10 ; great dilation of pupil and pallor of ear. 



4.11. Inject 5 mgm. nicotin. 



4.15. Stim. sy. for 10 sees., c = 10; great dilation of pupil and pallor of ear. 

 4.19. Inject 10 mgm. nicotin. 



4.24. Stim. sy. for 30 sees., c = 10; no dilation of pupil, slight pallor of ear. 



4.25. Stim. sy. for 60 sees., c — 10 ; no dilation of pupil, slight pallor of ear. 

 4.55. Stim. sy. for 60 sees., c = 10 ; no dilation of pupil, slight pallor of ear. 



5.5. Stimulation of the sympathetic on the opposite side caused no dilation of the 



pupil, but a slight constriction of the vessels of the ear. 



