174 INDIVIDUALITY IN ORGANISMS 



Those who hold that the nerve in normal condition 

 transmits without a decrement have usually maintained 

 that under depressing conditions the nerve behaves 

 in a different way from the normal nerve and that the 

 decrement exists only under these conditions. In view 

 of the fact that in the nerves of the lower animals a 

 transmission-decrement undoubtedly occurs normally, 

 and that in protoplasmic transmission in the absence of 

 nerves the decrement is even more marked, the grounds 

 for the belief that transmission without a decrement 

 occurs in the vertebrate nerve do not appear to be ade- 

 quate. It seems scarcely probable that the higher 

 degree of specialization of the vertebrate nerve has 

 brought about a fundamental change in the character 

 of transmission of such a nature that the decrement is 

 reduced to zero and transmission to an indefinite or 

 infinite distance is possible. The experiments along 

 this line prove only that with the very limited lengths of 

 nerve available the decrement under normal conditions 

 is very slight or inappreciable. Evidently the nerve 

 of the vertebrate, and particularly of the higher verte- 

 brate, is a much better conductor than undifferentiated 

 protoplasm or even than the nerves of lower animals, and 

 within the limits of the individual vertebrate body the 

 decrement is undoubtedly slight or practically absent 

 when the nerve is in good metabolic condition, but the 

 conclusion that there is no decrement in such cases 

 seems unwarranted. It is also highly improbable that 

 the nature of transmission in the cooled, partially 

 narcotized, or compressed nerve is essentially different 

 from that in the same nerve under normal conditions, 

 and since a decrement appears under depressing condi- 



