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264 BEHAVIOR OF THE LOWER ORGANISMS 



not found elsewhere in protoplasmic structures. The qualities of the 

 nervous system are the general qualities of protoplasm. Certain of 

 these general qualities have become much accentuated in the protoplasm 

 of the nervous system, while in the remainder of the protoplasm of the 

 metazoan body they are less strongly marked, being partially obscured 

 by differentiations in other directions. Most if not all of the funda- 

 mental activities which have been considered peculiar to the nervous 

 system may be demonstrated, as we have seen, in the Protozoa, yet in 

 them no nervous system exists. 



These facts show the necessity of guarding against overrating the 

 importance of the nervous system. It is doubtful if the nervous system 

 is to be considered the exclusive seat of anything; its properties are 

 accentuations of the general properties of protoplasm. Dogmatic state- 

 ments as to the part necessarily played by the nervous system in given 

 cases must be looked upon with suspicion unless supported by positive 

 experimental results. If acts objectively identical with "reflex actions" 

 and still more complex types of behavior may exist in the Protozoa with- 

 out the intervention of a nervous system, it is not impossible that they 

 may occur in the same manner in Metazoa, as Loeb has maintained. 

 Where a nervous system exists, we are not justified in dogmatically refer- 

 ring all phenomena of behavior to it, for other protoplasm exists too, and 

 may still retain some of the characteristics which it had in the Protozoa. 

 In an animal possessing a nervous system we cannot tell without experi- 

 mentation whether a given reflex action or other reaction depends on 

 the nervous system or not. The possibility always remains open that 

 the remainder of the protoplasm may perform the act in question by its 

 own capabilities, as it does in the Protozoa. In any animal, we are 

 justified in attributing exclusively to the nervous system only those prop- 

 erties which rigid analytical experimentation shows it alone to possess. 



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