16 BIOLOGY AND SOCIAL PROBLEMS 



pie nervous acts like the one just described than 

 that these animals have any real conscious ex- 

 istence. They are probably much more correctly 

 described as animal automata than as beings 

 possessing even a low degree of intelligence. 

 Many reflexes of the human body take place 

 with the certainty and precision of those just 

 discribed, but, unlike them, are associated 

 with consciousness. If we irritate the surface 

 of the eye by touching it, we involuntarily 

 wink. Here, then, is a simple reflex which is 

 associated with an irritating sensation, though 

 the response itself is involuntary. Sneezing 

 and coughing are similar reflexes. If we re- 

 peatedly strike a dog on one side of the mid- 

 dle of the back, he will begin scratching move- 

 ments with the hind leg of that side. Not only 

 are muscles thus reflexly brought into action, 

 but glands also serve as the efferent organs for 

 such reflex activity. When the surface of the 

 eye is irritated, not only does the lid move, 

 but the eye waters, that is, there is a reflex oper- 

 ation of the lachrymal glands whereby tears 

 flow. In addition to muscles and glands, elec< 

 trie organs and luminous organs, found among 

 fishes and other lower animals, are apparently 

 also reflexly excitable. 



