239 



CHAPTER XIV. 



THE ACTION OF CUTANEOUS 

 ANAESTHETICS. 



DRUGS APPLIED TO THE UNBROKEN SKIN. 



IT has been customary to relieve abdominal pain 

 by the application of hot fomentations containing 

 opium, to treat sprains and bruises with lead and 

 opium, and to smear on glycerin of belladonna for 

 the discomfort of white leg. What dyspeptic old 

 lady has not worn a belladonna plaster over her 

 heart, and what practitioner has not prescribed a 

 belladonna liniment for vague aches and pains ? 

 The rationale of the treatment has been that bella- 

 donna, opium, and menthol are alleged local 

 ancesthetics, and it is further supposed that they are 

 absorbed by the unbroken skin. The truth is that 

 they are not local ancesthetics, and that they are 

 scarcely if at all absorbed through the unbroken 

 skin. Neither aconite, cocaine, carbolic acid, bella- 

 donna, nor opium has any power to relieve pain 

 when appUed to normal, healthy skin. 



It has been well said that " You have not proved a 

 lie to be a lie, until you have shown how it came to 

 be believed." This is very true in science, and 

 especially in medical science. The use of belladonna 

 and opium to relieve local pain was an obvious 

 deduction from their great power, when given by the 



