EXTRACT XXXIX. B. 



ON A PHYSIOLOGICAL PHENOMENON CONNECTED 

 WITH THE INITIATION AND TRANSMISSION OF 

 NERVE IMPULSE THROUGH, OR BY, THE NERVE 

 TERMINALS. 



THE thought strikes us that the presence of cerebro-spinal 

 fluid, or a fluicl of like composition, is necessary at the 

 peripheral, or sensory, nerve endings, in order that special- 

 ised initial molecular changes may be communicated to the 

 terminal extremities of the axis cylinders preparatory to 

 the transmission of proper nerve impulses, and that this is 

 accomplished by its conveyance to, and storage in, the nerve 

 terminals, by means of the circulatory media of the nerve 

 fibres, and their attached peripheral expansions. This 

 doctrine will apply both to the systemic, or general, and 

 the sympathetic system of nerves in their afferent aspects. 



It may be also, and we think must be, that a similar, or 

 corresponding, cerebro-spinal lymph mechanism is necessary 

 to effect the passage of motor, or efferent, impulses from 

 the motor nerve terminals to the contractile elements of 

 the muscular fibres, both striped and unstriped. 



If this be true, we can perceive that channels for the 

 passage, or circulation, of the required fluid are ready pro- 

 vided in the inter-neurilemmar spaces of the nerve fibres, 

 sensory, motor, and sympathetic, and that the nerve ter- 

 minals, in a state of health, must always contain a sufficiency 

 to meet requirements. 



Normal aesthesia may be supposed to follow a physio- 

 logically normal condition of this provision, while anaesthesia 

 and hyper-anassthesia may be regarded as due, in like 



