88 THE PHYSIOLOGY OF THE COMMON CRAYFISH. 



do we mean by "being aware" and "knowing"? 

 Certainly it cannot be meant that the crayfish says to 

 himself, as we do, "This is dangerous," "That is nice ; " 

 for the crayfish, being devoid of language, has nothing to 

 say either to himself or any one else. And if the cray- 

 fish has not language enough to construct a proposition, 

 it is obviously out of the question that his actions should 

 be guided by a logical reasoning process, such as that 

 by which a man would justify similar actions. The 

 crayfish assuredly does not first frame the syllogism, 

 " Dangerous things are to be avoided ; that hand is 

 dangerous ; therefore it is to be avoided ; " and then act 

 upon the conclusion thus logically drawn. 



But it may be said that children, before they acquire 

 the use of language, and we ourselves, long after we are 

 familiar with conscious reasoning, perform a great variety 

 of perfectly rational acts unconsciously. A child grasps 

 at a sweetmeat, or cowers before a threatening gesture, 

 before it can speak ; and any one of vis would start back 

 from a chasm opening at our feet, or stoop to pick up a 

 jewel from the ground, "without thinking about it." 

 And, no doubt, if the crayfish has any mind at all, his 

 mental operations must more or less resemble those which 

 the human mind performs without giving them a spoken 

 or unspoken verbal embodiment. 



If we analj'se these, we shall fuad that, in man}^ cases, 

 distinctly felt sensations are followed by a distinct desire 

 to perform some act, which act is accordingly performed ; 



