Some Friends in Armor ill 



animal intelligence brings the inevitable conclusion that 

 we are powerless to penetrate even the outlying boun- 

 daries of that incomprehensible domain. As we de- 

 scend from the intelligence of man, from his exercise 

 of pure reason, through instinct, through so-called re- 

 flex action to the sentiency of one-celled organisms, we 

 find that at each receding level the barriers to that 

 awful frontier become more and more impassable. 



The mind of humans or what passes for such among 

 the lower animals is not a thing that can be subjected 

 to the crucible or the retort. It cannot be weighed or 

 measured. The instrument is yet undreamed of, which 

 can register in the slightest the difference in kind or in 

 degree between the mentality of mankind and the 

 abysmal consciousness of the protozoan. The analysis 

 of this thing which is without substance, form, or color, 

 but which is nevertheless a tremendously real entity, is 

 confronted by perplexities unknown to other investiga- 

 tions of the experimental worker. 



Without wishing to anticipate myself, I am con- 

 strained to admit at once that the fragments I have 

 gathered in regard to the status of the hermit crab's 

 intelligence have added but little to the meager balance 

 in its favor. Actuated entirely by instinct, prompted 

 solely by the exigencies of the moment, it is in none of 

 its pursuits guided by the faintest glimmer of reason. 

 In the conduct of its courtship, in the search for food, 

 in fact, in its entire deportment throughout the whole 

 tenor of its life, it is motivated by a mind that is little 

 superior, and in many instances inferior, in its mani- 

 festations to the movements of an automaton. 



The primary attribute that distinguishes intelligence 



