178 THE ACTION OF 



fat, but in the cells of the Malpighian layer of the 

 skin, and the injection must be made into the skin, 

 not into the fat. When the anaesthetic has been 

 properly given, the skin will be white, and will present 

 a flat-topped infiltration with a sharp edge, like that 

 which is so characteristic of erysipelas. To make 

 a satisfactory intradermic injection a small hypo- 

 dermic syringe is seldom good enough. One needs 

 a powerful syringe with a fine needle. An anti- 

 toxin syringe does excellently. 



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 

 anaesthetics, and it is further supposed that they are 

 absorbed by the unbroken skin. The truth is that 

 they are not local anaesthetics, 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 applied to the unbroken 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 



