154 ANIMAL INTELLIGENCE 



associations or the reverse. The mature dog has em- 

 bedded in his nervous system and psychic nature a 

 series of connections which, without any, reasoning 

 answer to warn him or the reverse, are perfectly 

 indifferent. 



However, new and mysterious sounds may alarm a 

 mature dog more than a puppy. 



The lower animals are more sensitive to concussions 

 than man, as shown by their behaviour prior to earth- 

 quakes, when there are slight oscillations of the earth, 

 wholly unperceived by man, yet causing alarm to the 

 domestic animals. 



I have noticed that puppies are very early stimulated 

 by concussions, but regret that I have not exact ob- 

 servations with fixed dates to report. 



One of the earliest indications of hearing is reflex 

 movement of the ears. These are quite distinct, of 

 course, from the voluntary movements often seen in 

 dogs and other animals. But similar, though less 

 marked, movements of the external ears may be 

 observed in man also, as any one may prove by asking 

 an individual to listen and determine the location of 

 a tuning-fork sounded behind him. These I have for 

 many years been accustomed to demonstrate to my 

 classes in physiology, though I have not noticed that 

 they are referred to in books. There seems to be no 

 relation between the extent of the reflex and the 

 voluntary movements of the ears, of which some people 

 are capable. When at concerts I have sometimes ob- 

 served them in great numbers and variety. 



Another matter that seems to have received scant 

 attention, if I may judge from the absence of printed 

 references, is the condition of the ears in puppies up 

 to a certain date. At birth the external ear is turned 

 back, and its internal aspect strikes one by its relatively 

 undifferentiated character, and the auditory meatus is 



