INTRODUCTION 21 



advantage when it is removed from the reach of central 

 influences than when its nervous connections are intact. 

 It is not unlikely that there are a good many human 

 beings suffering from indigestion of nervous origin who 

 would have less trouble if their stomachs and intestines 

 could be placed quite out of reach of brain and cord and 

 left to work as determined by their own intrinsic proper- 

 ties. According to this view, suspension of the motor 

 activities of the canal is a possibility easily realized. 

 Acceleration may also be effected, but cannot be held to 

 be so common and striking an occurrence. 



When the first clear instance of inhibition the case of 

 the heart was brought to the attention of scientists in 

 the year 1845 it was received with surprise and, at first, 

 with incredulity. All sorts of explanations were offered 

 for the phenomenon, with the intention of proving that 

 it was not a true suppression of activity. In course of 

 time, however, inhibition had to be recognized as a power 

 of the nervous system fully as direct and characteristic 

 as excitation. It is now fair to say, as a concise statement 

 of all which has gone before, that the duty of the nervous 

 system is to translate the energy of external stimulation 

 into nerve-impulses, to carry these to the central axis, and 

 to apply them through the efferent paths either to arouse 

 or to restrain the action of the contractile and secreting 

 tissues. The nature of the energy which is transmitted 

 along the nerves can best be discussed after we shall have 

 obtained some insight into the microscopic organization 

 of the nervous mechanism. 



