INNERVATION OF THE HUMAN SKIN 223 



Some Aspects of the Nervous System. 



It has been said with some truth that the telephone has struck 

 a mortal blow at such serenity of life as the Juggernaut Car of 

 modern progress has left us. But if it has done nothing else it has 

 furnished the physiologist with a good illustration when he sets 

 out to expound the functions and arrangement of the elements 

 of the central nervous system and its peripheral expansion. In 

 addition to this general light upon a great matter the vivid 

 experience of many an Englishman during the recent years of war 

 adds point to a subordinate phase of the general story of the tele- 

 phone, for it represents my contention as to the origin or initiative 

 of the sensorial areas of the mosaic under consideration. Modern 

 persons may be divided into two classes, those who want and those 

 who do not want the telephone, and the former may be sub-divided 

 into A, those who can, and B those who cannot get it (or could not). 

 A and B from the present point of view may be termed Receptors, 

 though to call the B people by that name is to speak Hibernically. 

 With this war-time experience in our minds, we may picture a vast 

 period of time during which the stimuli of pain, cold, warmth and 

 touch were hammering on the skin both before it began to lose its 

 chief hairy covering, and after that process had left man still a 

 hairy animal, but with much-diminished amount of his ancient 

 heritage. These stimuli fell upon the skin very much as the 

 class A, among telephone receptors, spent numerous fruitless 

 stimuli on Postmasters -General, Ministers in Parliament and in 

 " short " bitter letters to our bright little Daily Pope, and who yet 

 found themselves not " connected up," as the saying goes. There 

 is no knowing how long it was before they had enough effect 

 on the delicate nerve fibrils struggling up into the epidermis and 

 produced receptors or were " connected up " to the exchange or 

 central nervous system. I am inclined to liken the pain stimuli 

 to the short letters referred to, the cold and warmth stimuli to 

 those addressed to the Postmasters -General and the touch stimuli 

 to those which fell upon Ministers at question time. 



Another comparison of the peripheral portion of the nervous 

 system to common things has at times forced itself upon my mind 

 when reflecting on the stimuli which are continually assaulting the 

 skin, as I have watched on the Needles' Downs a flock of sheep on a 

 summer evening returning to their fold. As the sun begins to set 

 they are scattered over the western end of the Downs, still cropping 

 the short grass clothing those chalk and flint slopes which from 

 immemorial time has alone flourished there. They wander singly 

 or in small groups on such parts of the slope as the intrusive golfer 



