334 IRRITANTS AND COUNTERIRRITANTS 



be quite effective in. lumbago and sciatica. It is rarely used in mod- 

 ern medicine. 



4. Scarification. This consists of making numerous small in- 

 cisions with a knife or other instrument such as rubbing with needles. 

 The irritant may then be rubbed in and wiU have a greater degree 

 of action. 



5. Temperature. Cold applications are often used for their re- 

 mote reflex action, while some form of heat is used for local effect. 

 The actual cautery is often very serviceable for deep seated affections. 



6. Cupping, etc. Cupping or leeching simply brings about a 

 change in the distribution of blood to the parts. A small amount is 

 sometimes extracted in this manner. Leeches act in the same way 

 but are not used in modern medicine. See p. 110. 



7. Electricity is used as a stimulant to prevent atrophy of muscles, 

 in paralysis and as a counterirritant. 



8. Drugs. 



Uses of Irritants and Counterirritants. 



1. In skin diseases. 



2. Promote secretion of sweat. 



3. For reflex action by affecting the central nervous system espe- 

 cially the medulla. 



4. As counterirritants. 



5. Relieve pain. 



(a) To change the distribution of blood and diminish deep 

 chronic inflammation. 



(b) To remove exudate from connective tissue in a similar 

 manner. 



(c) Relieve pain. 



(d) Tonic action. 



1. Skin Diseases. Some long standing or chronic forms of skin 

 disease are often benefited by the action of an irritant. This is par- 

 ticularly so in ulcers, chronic eczema, and slow healing wounds. 

 Some of the milder irritants are usually employed such as the bal- 

 sams, tar, or light painting with iodine. 



2. Promote Diaphoresis (see diaphoretics). 



3. Reflex Irritation of Central Nervous System. They may 

 be used in this case to arouse the system in collapse and shock, and in 

 narcotic poisoning. They may be given subcutaneously or by in- 

 halation (ammonia). In the latter case the action is produced by 

 irritation of the trigeminal nerve. 



4. Counterirritants. (a) Local changes in the circulation of 

 parts remote from the point of application can be accounted for in 

 two ways : through a continuity with the seat of irritation, or by re- 

 flex action. In the former case an increased vascularity of the skin 



