THE PROBLEM OF LEARNING I73 



apparatus during the last few years that one is at 

 a loss to know even the meaning and use of the 

 myo-esthesiometer, the dynamometer or the 

 schesi-esthesiometer, each of which is a specially 

 devised apparatus to test muscular sensibility, 

 motor fatigue or static sensations. At the 

 present, much time is being devoted to methods 

 of study and since they are relatively new, they are 

 correspondingly technical. But all of these 

 special devices are used to examine some form of 

 activity that can be tested over and over again. 



As indicated in the preceding chapter man has 

 his entire nervous system in common with higher 

 animals and the higher animals have theirs in 

 common with the lower. All of the vertebrates 

 have uniform external receptors (sense organs), 

 similarly placed on the body and responsive to the 

 same form of vibrations and solutions. Each of 

 these receptors is connected by a sensory nerve 

 with either the spinal cord or the "old brain." 

 Through these doors enters all of man's informa- 

 tion. 



For all of those who wish to approach this 

 problem through biology and the fundamental 

 laws governing the actions of all protoplasm, there 

 are a few generally accepted facts that must be 

 accounted for In any hypothesis. First, when an 

 energy change (vibration) or solution change 

 (chemical change) Initiates a stimulus on a nerve 



