BIOTIC STRUCTURE AND BIOTIC ENERGY 9 



pose the nerve is being stimulated in the usual manner from an 

 ordinary induction machine giving 100 interruptions a minute, then 

 there will be 100 nerve impulses passing in each minute, and the 

 period of activity belonging to each being approximately TO^TTTF 

 second, it follows that the nerve tissue is active for ylSrJro of its 

 time, and resting or recuperating for iVoVo of its time. That is to 

 say, for 1 per cent, of working time there is 99 per cent, of resting 

 time. Why, under such conditions, should the nerve become 

 fatigued even if it be stimulated for hours ? 



The effects of increasing the rapidity of the exciting discharges 

 also show that the above is the true explanation of the enigma of the 

 infatigability of nerve. As the rate of stimulation is made greater 

 and greater, the strength of the individual stimuli must be enor- 

 mously increased in order to get the threshold effect of commencing 

 response in the attached muscle. Further, as the limit of 10,000 

 stimuli per second is reached, the nerve material ceases to respond 

 to the excitation, and becomes quiescent even to maximal stimuli. 

 It is for this reason that Tesla could show that with a smooth, 

 rapidly alternating current even of high voltage lamps can be lit 

 up with people's bodies forming part of the circuit, without the 

 subjects of experiment being even conscious directly of the passage 

 of the current through their bodies. Here the rate of oscillation is 

 above the sympathetic point for the oscillation of the crystallo- 

 colloids which form the protoplasm of the tissue, and hence they 

 no longer excite it, any more than the ultra-violet rays affect the 

 crystallo- colloids of the retinal cells. Every living physiological 

 machine or cell possesses its distinctive colloids, and hence its 

 specific rate of oscillatory activity. 



The views and experiments of Macdonald in regard to the causa- 

 tion of the nervous impulse are here of great interest. This observer 

 has shown that during activity of nervous tissues there is a detach- 

 ment of certain crystalloids from the active portion of tissue which 

 continues only so long as activity lasts, and in the period of resting 

 is followed by recombination. Macdonald refers to the well-known 

 effects of electrolytes in altering state of aggregation, etc., and bases 

 his views of nervous activity upon such recurring combination and 

 dissociation between the active chemical components of the tissue. 

 Similar effects in regard to variation in distribution of electrolytes 

 accompanying variations in tissue activity have been experimentally 

 obtained by A. B. Macallum. 



