INHIBITION AND CARDIAC VAGUS 117 



in the preliminary pauses of intestinal activity, and the 

 peculiar phenomena observed in the heart, are not classed 

 together under one word of very doubtful connotations. 



It is, of course, stated, perhaps almost with violence, 

 that inhibition and inhibitory nerves exist, that the evi- 

 dence for them is overwhelming. Certainly the observa- 

 tions show that action ceases at times very suddenly. 

 Activity is cut short, and a muscle with contrary action 

 comes into play. Bell's "muscular sense" consisted, I 

 take it, not only in central messages, but in an infinite 

 series of reflexes. So with Duchenne's "articular sense," 

 the loss of which, in his opinion, gave rise to locomotor 

 ataxia. It is barely conceivable that the paths of all 

 such delicate reflexes are known. Since the nerve cells 

 are not so distantly related to muscle cells, which are 

 peculiarly conductive, it can be imagined that many 

 muscular reflexes occur even without nerves, while few 

 neurologists, I imagine, will be ready to declare that the 

 whole nervous anatomy of the body is now and for 

 ever mapped out. These fields should be explored before 

 resorting to a rough-and-ready statement of central " in- 

 hibition " in every case of suddenly arrested action. Such 

 arrests take place under conscious, if instinctively recog- 

 nized, stimuli ; but since the constant course of evolution is 

 devolution and " short-circuiting," following the laws of 

 energetics, the naturally simpler view should be taken. 

 If so, in every case of inhibition some short-circuiting reflex 

 should be looked for, if the mere cessation of afferent sensory 

 messages will not account for the phenomena. It seems 

 as if inhibition had become a physiological Mesopotamia — a 

 very comforting word. Certainly mystery after mystery has 

 been crammed into it, and once established as " explana- 

 tion " the endeavour is to explain it, with what results the 



