112 NERVOUS SYSTEM. 



clusivel j motor properties. The error in these observations, 

 however, was early pointed out by Rousseau, whose experi- 

 ments were fully detailed by Bernard before they were pub- 

 lished separately. 1 Rousseau found that when galvanism 

 was applied to a mixed nerve still connected with its cen- 

 tres, two galvanic currents were established ; the one taking 

 the shorter course through that portion of the nerve includ- 

 ed between the poles of the battery, and the other, called the 

 " derived current," taking an opposite direction through the 

 nerves and the tissues. It is evident that the derived cur- 

 rent would be inverse for the nerve when the shorter cur- 

 rent is direct, and vice versa. Now if the extent of nerve 

 included between the poles of the battery be short, the de- 

 rived current would predominate, and we would seem to 

 have contraction with the closure of the inverse and the 

 opening of the direct current. This fact was fully demon- 

 strated by Rousseau, who devised a little apparatus for neu- 

 tralizing the derived current, when the phenomena follow- 

 ing the application of the currents to the nerves attached 

 were the same as those observed in divided nerves. 2 In 

 1859-'60, shortly after these experiments were published, 

 we repeated them before a medical class, and have no doubt 

 as to the accuracy of the results. The experiments of Rous- 

 seau have since been confirmed by Chauveau ; 8 and Mat- 

 teucci; 4 in his later publications, acknowledges the error of 

 his first observations, though Longet still adheres to his ori- 

 ginal deductions. 6 



Induced Muscular Contraction. A curious phenomenon 



1 ROUSSEAU, in BERNARD, Lemons sur la physiologie et la pathologic du systeme 

 nerveux, Paris, 1858, tome i., p. 170, et seq. 



2 Loc. dt., p. 181. 



3 CHAUVEAU, Effeis physiologiques de Peledricite. Journal de la physiologie, 

 Paris, 1860, tome in., p. 458, et seq. 



4 M ATTEUCCI, Phenomenes physico-chimiques des corps vivants. Revue des cours 

 xdentifiques, Paris, 1867-'68, tome v., p. 508. 



6 LONGEI, Traite de physwlogie, Paris, 1869, tome iii., p. 187. 



