66 DARWINISM AND THE PROBLEMS OF LIFE 



young animal to imitate. The impulse of imitation is 

 peculiarly strong in children and young animals. It is 

 an impulse that their parents have in their young days, 

 and have transmitted to their children. This impulse is 

 the same thing as instinct. 



But are we justified in speaking of instinct in the 

 higher animals, and even in man? Are they not 

 endowed with reason, and is it not this that controls 

 their actions ? ^ 



No. There are instinctive actions even in man. Pass 

 your hand suddenly before the eye of another, and you 

 will see the eyelid close immediately, without the 

 other being conscious of it.^ This closing of the eye- 

 lid is called a reflex action, and if we seek to understand 

 it we must first examine more closely the nerve-tracks 

 in the body. 



There are two kinds of nerves. The first group is 

 called the sensory nerves ; these are they that pass from 

 the skin to the brain (and spinal cord), and conduct 

 thereto every touch from without, every twinge of pain, 

 and every impression made on the senses. When the 

 brain has received the impression in this way, it 

 telegraphs back to the spot whence the message came. 

 For this it uses the motor nerves, which pass from the 

 brain to the external surface and the muscles of the 



^ Biichner and Brehm attack the idea of instinct generally, but it is 

 the old idea of Descartes which assigned reason to man alone, and 

 only credited animals with instinct. They both entirely forget that 

 :here may be other meanings of instinct. Groos draws attention to 

 [his. 



' In what follows I pass over the various theories of instinct, and only 

 jive the one that has been most accepted of late. This is the theory 

 3f Weismann, and much the most probable. 



