TICKLE AND PAIN 



23i) 



fibres. The hairless surfaces when touched only give rise to a 

 sensation of tickle when the touch is intermittent or strokintv. It 

 need not necessarily be light, e.g. the sole of the foot may be tickled 

 intensely by rubbing vigorously with a hard nail brush (Greig). 

 The receptors for this type of stimulation arc also phasic, and 

 depend on pressure in the sublying tissues (Fig. 01). 



The muscles at certain places are extremely sensitive to inter- 



PACINIAN 



CORPUSCLE 



D££P PK£SSL:-Z) 



NERVE 



£ND BULB 

 KR/^ use's 

 'HEAT OR COLO '1 



M£ISShl£RiS 



\ corpuscle 

 (touch) 



NERVE PLEXUS 

 OF A HAIR. 



I NERVIL 



NERV£ 



fJ£Rve PLEKUi 

 f'ROM CORI^EA 



I pain) 



Fig. 61. — Various types of receptors found at or near the surface of the body. 



mittent pressure, e.g. at ribs and knees. Here the stimulus is 

 distinct pressure, and is allied with the sense of pain. Continued 

 tickling has been used as a means of torture by Eastern peoples. 

 Simon de Montfort is said to have put the Albigenses to death by 

 tickling, and a certain Anabaptist sect, unwilling to shed blood, 

 are reported to have used this method of executing offenders. 



3. Pain is aroused by mechanical, thermal or chemical stimuli 

 of sufficient intensity, and is considered by some to be caused by 

 overstimulation of any receptor, e.g. too loud a sound, too bright a 



