CUTANEOUS ANAESTHETICS 183 



Moreover, a recognition of the failure of drugs saves 

 useless expense, and may banish from patients' 

 houses some of the commonest of powerful poisons. 

 Belladonna liniment, for instance, has been respon- 

 sible for an immense number of alarms, illnesses, 

 and even fatalities. 



COUNTER-IRRITANTS. 



In order to have a clear conception of the subject 

 before us, let us take three illustrations of the use 

 of counter-irritants : (i) The application of diluted 

 tincture of capsicum to the loin for lumbago ; (2) 

 Rubbing in soap liniment for a painful sprained 

 ankle ; and (3) Putting a blister behind the ear for 

 earache. 



These are old and tried remedies ; have we any 

 evidence of their value ; and if so, how do they act ? 

 Why should an irritation of the cutaneous nerve- 

 endings make any difference to the sensations 

 received from deep fasciae, synovial membranes, or 

 the middle ear ? 



No one can deny the great relief given by the above 

 measures. The effect of the first is often marvellous, 

 to which some of us can bear personal testimony. 

 The liniments and other applications mentioned in 

 the group we have just considered have traded for 

 their reputation on the counter-irritation they 

 produced. We have the analogous means of 

 relieving pain, the use of hot fomentations and of 

 the thermo-cautery, waiting for an explanation on 

 similar lines. 



Before considering why counter-irritants relieve 



