PLANTS 5 



and no distinction is needed between afferent and efferent pathways. 

 The only instance known of special tissues for the conduction 

 of impulses is in the sensitive plant group and here it is quite defi- 

 nitely proved that living tissues are not necessary for the conduc- 

 tion of impulses and are in no sense comparable to the conductive 

 tissues of complex animals. 



