REFLEXES 103 



Reflexes Other than Movements. So far we have 

 spoken of reflexes as though they were necessarily 

 acts of the muscles. The conception must now be 

 made broader. Certain reflexes have a negative or 

 inhibitory character. A dash of cold water may cause 

 one to hold the breath momentarily and perhaps at the 

 same time the heart may " drop a beat." The suspension 

 of breathing and the omission of the heart's contraction 

 are true reflexes, but instead of being movements they 

 consist in the suppression of movements which were 

 due to occur. 



There are also reflexes which are executed by glands 

 instead of muscles. A gland is an organ which pre- 

 pares and discharges some chemical product. Either 

 the action of the gland or its product may be described 

 by the word secretion. Some glands, like the kidneys 

 and the liver, continuously evolve their secretion; others 

 nearly or quite intermit activity. Glands of the latter 

 type are often found to be as distinctly subject to 

 nervous government as are the skeletal muscles. The 

 nerves which stretch out to them from the central 

 organs are spoken of as secretory nerves. They are 

 efferent but not motor according to our definitions. 



One of the most familiar examples of the reflex ex- 

 citation of secretion is afforded by the flow of tears when 

 this results from a cinder in the eye. As there are 

 winking movements at the same time we have here a 

 particularly good demonstration of two kinds of reflex 

 action. When the tears start from emotional causes the 

 reflex character of the act is not so plain. A hot or an 

 acid fluid taken into the mouth produces a reflex secre- 

 tion of saliva. Warming the skin will call forth a reflex 

 discharge of perspiration. 



Psycho-reflexes. In characterizing the standard 

 reflex we insisted that consciousness does not enter into 

 it as an essential feature. We may notice our own re- 

 flexes but to observe is not to control them. Often 

 they run counter to our desires; we may be compelled 



