248 Animal Life and Intelligence. 



was left free for those who were present at the experiment. 

 A bat, measuring about one foot from the tip of one wing 

 to that of the other, was let loose in the room when it was 

 quite dark, *' and it was distinctly heard flying about all 

 over the room, but never once did it touch a string or stop 

 flying. It several times came quite near to the spectators, 

 so that they could feel the vibration of the air in their faces. 

 The experiment was continued for half an hour. Then, 

 when the door was opened and light let in, the bat stopped 

 flying, and settled down in the darkest corner." Now, 

 here it may be said that, although the room was dark to 

 human spectators, there may have been light enough for 

 a bat to see his way. The cruel experiments of Spalanzani, 

 however, who put out the eyes of bats and obtained a 

 similar result, seem to show that the animal is guided by 

 some sense other than that of sight. 



The crustaceans and many insects are covered with a 

 dense armour, and it might be supposed that in them 

 there could be no sense of touch. But this sense is by 

 no means absent. Seated on the 

 tough integument are delicate little 

 hairs, to the base of which a nerve- 

 fibril passes through a perforation in 

 the integument. These are specially 

 numerous in the antennae of insects. 

 In yet lower organisms we know 

 in some cases the manner in which 

 24.— Touch-hair of they are sensitive to touch: but in 

 ^^.,touch-hair;'c«., cuticle; ^ great number of cases, although 

 cerico'nrctX\Un^erv?paSg observatiou shows that they are thus 

 faS?eJ'Sf Thl'yrgtn't seusitive, we know nothing definite 

 eS orrs-acceLorrSu-; as to how the surface is specially 



which are not figured here. ^^^^^ ^^ ^^^^.^^ ^^^ Stimuli. EvCn 



the primitive amoeba, however, is sensitive in the sense 

 spoken of on p. 8 ; that is to say, it reacts under the 

 influence of a stimulus. 



Closely associated with the sense of touch is the 



