ON THE MAMMALIAN NERVOUS SYSTEM. 



385 



from the canal ; it was then connected with the electrodes exactly as in the case of 

 the Cat. 



The lower section and exposure occurred at the level of the 1st lumbar, and the cut 

 surface of the columns was then stimulated as in the preceding case. The necessary 

 strength for minimal excitation was only found when the coil was 2000. The 

 anterior columns evoked no definite effect, but excitation of the laterals evoked 

 large effects, left 190, right 225, whilst similar excitation of the posteriors evoked 

 smaller deflections, left 112, and right 120. 



Fig. 15. 



The results of these two typical experiments will be rendered still more obvious 

 by the annexed figure, in which the value of the excitatory effects in the Cat and 

 Monkey are displayed in a graphic form. It will be seen how completely the relative 

 size of the effect evoked by stimulation of the two kinds of column is reversed in 

 the two animals. (See fig. 15.) 



(b.) Average of Experiments. 



We will now take the average of the observations in which the condition of the 

 animal, &c., was, as far as possible, the same throughout, and the effect evoked in the 

 dorsal cord by stimulating the lumbar columns accurately noted. 



MDCCCXCI. B. 



3 D 



