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INTRODUCTION TO NEUROLOGY 

 TABLE OF PHYSICAL VIBRATIONS 



Similarly, the chemical senses, taste and smell, reveal to us only 

 a very small number out of the total series of actual excitations 

 to which our sense organs are exposed. Our organs of taste, in 

 fact, can respond to only four types of chemical substances, with 

 only four subjective sense qualities, viz., sour, salty, sweet, bitter. 

 The organs of smell respond to a larger range of chemical stimuli 

 and to far greater dilutions, i. e., the threshold of sensation is 

 far lower for smell than for taste. 



Many of the lower animals have very different limits of sus- 

 ceptibility to the kinds of stimulation which we have just been 

 considering, and in some cases they have sense organs which are 

 attuned to respond to a quite different series of environmental 

 factors than are our own, as, for example, the lateral line sense 

 organs of fishes. We can form no idea how the world appears to 

 such organisms except in so far as their sensory equipment is 

 analogous with our own. 



