170 THE POPULAR SCIENCE MONTHLY. 



in the expression of ordinary fear, which might receive an explanatory 

 light from ancestral conditions, even infra-human ones. In ordinary 

 fear, one may either run, or remain semi-paralyzed. The latter condi- 

 tion reminds us of the so-called death-shamming instinct shown by 

 many animals. Dr. Lindsay, in his work on "Mind in Animals," says 

 this must require great self-command in those that practice it. But 

 it is really no feigning of death at all, and requires no self-command. 

 It is simply a terror-paralysis which has been so useful as to be- 

 come hereditary. The beast of prey does not think the motionless 

 bird, insect, or crustacean dead. He simply fails to notico them at 

 all ; because his senses, like ours, are much more strongly excited by 

 a moving object than by a still one. It is the same instinct which 

 leads a boy playing " I spy " to hold his very breath when the seeker 

 is near, and which makes the beast of prey himself in many cases 

 motionlessly lie in wait for his victim or silently " stalk" it, by rapid 

 approaches alternated with periods of immobility. It is the opposite 

 of the instinct which makes us jump up and down and move our arms 

 when we wish to attract the notice of some one passing far away, and 

 makes the shipwrecked sailor frantically wave a cloth upon the raft 

 where he is floating when a distant sail appears. Now, may not the 

 statue-like, crouching immobility of some melancholiacs, insane with 

 general anxiety and fear of everything, be in some way connected with 

 this old instinct ? They can give no reason for their fear to move ; 

 but immobility makes them feel safer and more comfortable. Is not 

 this the mental state of the " feigning " animal ? 



Again, take the strange symptom which has been described of late 

 years by the rather absurd name of agoraphobia. The patient is 

 seized with palpitation and terror at the sight of any open place or 

 broad street which he has to cross alone. He trembles, his knees bend, 

 he may even faint at the idea. Where he has sufficient self-command 

 he sometimes accomplishes the object by keeping safe under the lee 

 of a vehicle going across, or joining himself to a knot of other people. 

 But usually he slinks round the sides of the square, hugging the houses 

 as closely as he can. This emotion has no utility in a civilized man, 

 but when we notice the chronic agoraphobia of our domestic cats, 

 and see the tenacious way in which many wild animals, especially 

 rodents, cling to cover, and only venture on a dash across the open 

 as a desperate measure even then making for every stone or bunch 

 of weeds which may give a momentary shelter when we see this 

 we are strongly tempted to ask whether such an odd kind of fear 

 in us be not due to the accidental resurrection, through disease, of 

 a sort of instinct which may in some of our ancestors have had a 

 permanent and on the whole a useful part to play ? 



In a subsequent paper I shall try to consider man's remaining in- 

 stincts in a similar way. 



