46 COMPARATIVE PHYSIOLOGY OF THE BRAIN 



directly from the dendrites to the peripheral fibre." It 

 was possible to perform the operation in Carcinus 

 on the ganglion-cells which innervate the muscles of 

 the second antenna. The cutting of the peripheral 

 nerves (Antennarius secundus) that go to these gan- 

 glion-cells immediately causes a complete paralysis of 

 the antennse, a proof that the fibres of these nerves 

 are the only conductors of the stimulus which can 

 call forth a reflex movement of these antennae. But 

 when Bethe removed the ganglion-cells, without in- 

 juring the neuropile of the second antenna, " the 

 second antenna retained its tonus and its reflex irrit- 

 ability. It does not hang down limp, but remains 

 stiff and in the normal position. When stimulated, 

 it is withdrawn, but is stretched out again when the 

 stimulation ceases. From this it is evident that the 

 ganglion-cells are not necessary for reflexes. The re- 

 flex arc either does not pass through the ganglion- 

 cells or does not need to pass through them. It is 

 further apparent that the ganglion-cell has nothing to 

 do with the tonus of the muscles, and that the per- 

 manent influence which the central nervous system 

 exercises upon the tension of the muscles is not pro- 

 duced in the ganglion-cells (6)." 



This experiment, even if it be correct, adds no- 

 thing of importance to our conclusions. If the reflex 

 arc acts only as a quick protoplasmic conductor, the 

 question whether the stimulus has to pass through the 

 ganglion itself or not becomes of secondary import- 

 ance. 



