390 



BIOLOGY. 



[BOOK vi. 



The same effect moreover is produced by the simple section of 

 the corresponding sensitive nerves. The muscular tonus results 

 consequently from a veritable reflex action, in which the brain 

 does not at all participate, forasmuch as, by its separation 

 from the encephalon, the spinal marrow, so far from losing its 

 reflex power, possesses it on the contrary in a very high degree. 



Multipolar ganglionary cell of the spinal marrow of the ox : a, cylinder-axis ; 6, prolongations 

 of the substance terminating in fibres excessively fine. 



If, for instance, we pinch the foot of a decapitated frog, the 

 animal immediately withdraws it with much more energy than he 

 did in his state of integrity. If we pinch with more force the 

 reflex action is irradiated on the other members. In a frog 

 poisoned by strychnine and decapitated, the smallest contact at 



