441 



3. The first effect on the motory functions of the nerve is that of 

 increased excitability. 



4. This increase in its turn subsides, until all the parts below the 

 refrigerated portion of the nerve are paralysed, owing to the inter- 

 ruption of its conductivity. 



5. In this paralytic condition the muscles remain contracted to a 

 certain extent, and the inner fingers in a state of flexion. 



6. The first thermal effect of cold on the nerve is frequently a fall 

 of temperature of 0'5 Centigrade at the inner fingers below that of 

 the outer fingers. 



7. As the nerve becomes paralysed, the temperature of the two 

 inner fingers rises above that of the outer to the extent of 5 or 

 Cent. This is owing to the paralysis of the vascular nerves and 

 vessels of the parts supplied by the ulnar nerve, and is of the same 

 nature as that in the ear after section of the sympathetic nerve, 

 where, as I have demonstrated, the temperature may be lowered or 

 increased at will by acting on the nerve by galvanism. 



8. In my experiments on the sympathetic*, I have observed an 

 increase of 10 Cent, on the side operated on over that of the sound 

 side. In the above observations on man the increase at the inner fingers 

 was = 5 Cent. ; and it is probable that in cold weather a much 

 greater difference will be found in the temperature of the two sides, 

 because as the range is between blood-heat, which is the maximum, 

 and the temperature of the part before the experiment, the extent of 

 the range is much greater in cold weather than in the present month 

 of August. 



9. While the temperature of the inner part of the hand is rising, 

 that of the outer decreases, on account of the diversion of part of the 

 blood of the radial into the ulnar artery. The same effect is wit- 

 nessed after section of the sympathetic, where a fall of temperature 

 of the sound ear coincides with elevation of temperature in the 

 opposite ear. 



10. After the removal of the refrigerating body, the nerve quickly 

 regains all its original powers, except that the normal equilibrium of 

 temperature of the two sides of the hand is but slowly restored. It is 

 probable that this is to be attributed to the slowness of contraction 

 of the organic muscular fibres of the ulnar artery. 



* Vide Comptes Rendus de 1'Acad. de Sciences, February 1853. 

 VOL. XI. 2 I 



