ABNORMAL IRRITABILITY PRODUCED BY SALTS 703 



Ca ions as the effect of the sodium-fluoride and similar 

 solutions, I wish to state that I consider it possible that 

 solution may have other effects which play a r6le in these 

 phenomena. 



IV. THE EFFECTS OF SODIUM FLUORIDE AND CORRESPONDING 

 SOLUTIONS UPON THE NERVE 



If we try the experiments described above on curarized 

 muscles we get little or no result. This would indicate that 

 the contact-reaction is not due to an effect of these solutions 

 upon the muscle but upon the nerve elements in the muscle. 

 There is a second possibility, namely that curare, although 

 it does not abolish the electrical irritability of muscle, may 

 yet alter its substance enough to prevent the effects of con- 

 tact stimuli, or prevent the formation of the hypothetical 

 surface layer. 



It may be said with certainty that sodium-fluoride, sodium- 

 citrate, and the corresponding solutions act upon the nerve 

 in a way altogether different from that in which they act 

 npon muscle. If we put the nerve alone (without the muscle) 

 into one of these solutions which contains 1 gram-molecule 

 in about ten liters, as a rule nothing will happen during 

 the first five minutes. The removal of the nerve from the 

 solution will not call forth a contraction of the muscle. After 

 about five minutes the muscle will begin to twitch rhythmic- 

 ally, and very soon the muscle will shorten steadily until it 

 reaches a high degree of tetanic contraction. This twitching 

 continues as long as the nerve is in the solution. As soon 

 as the nerve is taken out of the solution and exposed to the 

 air the muscle relaxes more or less completely, and the 

 twitchings become less numerous. As soon as the nerve is 

 put back into the sodium- citrate solution the contraction in- 

 creases again and the twitchings become more powerful. 

 This may be repeated very often. It is obvious that the 



