40 Journal of Comparative Neurology. 



sidered by Bethe ; but many a neurologist who is not acquaint- 

 ed with the nervous system of invertebrates is apt to become a 

 victim to the ignorance of this difference. The very fact that 

 Bethe goes to the text-books of physiology and anatomy for his 

 ' authority ' of the use of the word ' nerve-cell ' ; and that he 

 seems to seriously believe that men familiar with the * neurone- 

 theory ' proper, speak of memory-cells, etc. in the sense of 

 ' cell-bodies ' for memories, ignoring the processes, would force 

 us not to take his word ' Nervenzelle ' as a serious histological 

 expression. ^'''^ A 'nerve-cell' of an arthropod after Bethe's 

 nomenclature is only a very small part of a ' nerve-cell ' in the 

 modern sense of the word neurone ; the size of the processes of 

 those small cell-bodies is such as to warrant the viability of the 

 tissue for a period of two to three days, just as we know that a 

 peripheral nerve in man, when cut through, preserves its elec- 

 trical excitability for at least two days, during which period the 

 excitability both to the faradic and to the galvanic current may 

 even be slightly increased (similar to what is mentioned in the 

 experiment on the arthropod) ; then begins a gradual diminu- 

 tion and only at the end of the first week or even as late as the 

 middle of the second, do we find the minimum excitability. 

 With perfect knowledge of this fact, we maintain what we said 

 concerning the ' motor neurone, ' and the only consequence of 

 Bethe's experiment on our general view would be this : that, if 

 we could destroy the nucleus of the segmental efferent neurones 

 without injuring the rest of the cell, the function of the cell 

 would probably last at least as long as the excitability of a cut 

 nerve. Between this and the extermination of the ' neurone- 

 theory ' there is a long distance. 



The rest of the paper is devoted to a noteworthy sketch 

 of a physiological conception of psychic activity, culminating 

 in the idea, that all psychic activity is the play of the outside 

 world on the fibril net-work of the nervous system. 



While Bethe keeps in the main carefully to the description 

 of the fibrils and to his experiment, Nissl (3) takes a far broader 

 sweep in his apotheosis of the * gray matter. * The article is 

 psychologically interesting, but difficult to render in abstract. 



