2 30 THE POPULAR SCIENCE MONTHLY. 



saw that he, too, was for that world a mirror worthy of love. He was full of re- 

 ligion and full of the holy spirit ; and therefore he appears to us solitary and 

 uaequaled, master in his art, but lifted above the profane, without disciples, and 

 without right of citizenship anywhere." 



That riglit of citizenship you are now about to confer on him. 

 Your monument will be the link between his genius and the earth. 

 His spirit will brood like a guardian angel over the spot where his 

 rapid journey among men came to its end. Woe to him who, in pass- 

 ino- by, should dare to level an insult at that gentle and pensive figure ! 

 He would be punished as all vulgar hearts are punished by his very 

 vulgarity and his impotence to comprehend the divine. Spinoza, 

 meanwhile, from his granite pedestal shall teach to all the way of hap- 

 piness he himself had found ; and for ages to come the cultivated man 

 who passes along the Pavilioengragt will inwardly say, " It is hence, 

 perhaps, that God has been seen most near ! " Contemporary Review. 



--- 



TRANSMISSION OF EXCITATIONS IN SENSORY 



NERVES.^ 



By PAUL BERT. 



PHYSIOLOGISTS are as yet by no means agreed whether the 

 nerves which, from their special functions, have been termed 

 motor and sensor nerves, are in their essential properties identical or 

 different ; in other words, whether a sensor nerve can transmit excita- 

 tions whose result is motion, and vice versa. We do not even know 

 whether an excitation produced midway in the length of a nerve is 

 simultaneously j^ropagated in both directions, centrifugally and cen- 

 tripetally. The admirable experiments made by Pliilipeaux and Vul- 

 pian to determine these knotty questions are, as Vulpian was the first 

 to observe, susceptible of a different interpretation from that unani- 

 mously put upon them by the world of science. 



Such being the state of the case, I thought it advisable to take up 

 again an experiment I had made in 1863,^ but which I had neglected 

 to prosecute, in view of the apparently far more conclusive and far 

 more general results obtained by the able experimenters just named. 

 This experiment I have now completed, and strengthened against any 

 objection that might have been raised against it. 



If we pinch a sensor nerve at any point of its length, the pain that 

 is felt cleai'ly shows that the excitation is propagated in the centripe- 

 tal direction ; but of a centrifugal propagation we know nothing, for 

 the very simple reason that at the terminal extremity of the nerve 



' Translated from the French by J. Fitzgerald, A. M. 

 "^ Comptes rendns de la Sociele de Biologie (1863), p. 179. 



