CHAPTER II. 



EXPEESSION. 



The term " expression " explained^Speech expressive of life ; 

 speech a criterion of life The uniform coexistence of two 

 phenomena makes the one an expression of the other Abstract 

 properties, and their objective signs; criteria of mind Com- 

 parison of an idiot, and an intelligent man Certain sounds 

 and a tracing of the pulse express the action of the heart 

 Signs due to an afferent force ; action of the sight of an object 

 upon children ; a thermometer indicates heat ; the sensitive 

 flame The telephone exhibits impressionability ; a receptive 

 part, an expressive part, and an additional force thrown in 

 The phonograph exhibits localized impressionability, which 

 is permanent Impressionability and retentiveness in a child 

 Expression, direct and empirical Impressionability and 

 retentiveness Nutrition ; its signs Movements in plants ; 

 pulvini, by unequal growth Expression by form, colour, 

 temperature Vital processes can only be studied by their 

 expression ; the importance of appreciating this in biological 

 work Summary. 



"EXPRESSION," in its widest signification, is the 

 outward indication of some inherent property or 

 function. An expression is a physical sign which 

 is accepted as a criterion of the property, because 

 the two are found by experience to be more or 

 less uniformly coexisting phenomena; and if the 

 manifestation of the special expression (or physical 



