CAUTERISATION. 15.'{ 



XL— CAUTERISATION. 



The destruction of tissue by chemical substances or by burning 

 is termed cauterisation. Such chemicals are comprised under the 

 general heading of caustics, whilst the red-hot iron or other heated 

 instrument is termed the actual cautery. Cauterisation produces a 

 scab or scar. The dead tissue is separated by reactive inflammation, 

 and is cast off ; healing follows by granulation. Apart from 

 destroying diseased tissues and stimulating repair in strained or 

 chronically inflamed tissues, cauterisation is often invoked merely 

 to produce very active counter-irritation, sometimes to hasten cica- 

 trisation, or to close bleeding vessels by causing contraction with 

 thrombus formation, and thus to check hemorrhage. 



Chemical caustics may be divided into fluid and solid. Fluid 

 caustics can be applied in small quantities with a brush, glass rod, 



Fig. 210.— Line firing iron and detachable handle. 



or pledget of cotton wool, etc., to the point to be cauterised, care 

 being taken never to apply so much as to render possible the spread 

 of the caustic beyond its intended position. If considered necessary 

 exactly to delimit the extent of tissue to be cauterised the skin may 

 be shaved, and a plastic containing an aperture of the desired size 

 applied, or a mass of soft plaster may be formed into a roll and 

 affixed to the skin around the point to be operated on, forming a 

 little basin to receive the caustic and protect adjacent parts. 



Of fluid caustics may be mentioned : 



Sulphuric acid, which acts very rapidly and powerfully on account 

 of the energetic way in which it removes water from living tissues 

 and coagulates albumen. It produces a hard black scab, which 

 remains in position a very long time. 



Fuming nitric acid produces a yellow scab, which is at first softer 

 than that produced by sulphuric acid, but later becomes dry and 

 hard. The yellow colour is due to the formation of xanthoproteic 

 acid, a combination of nitric acid with albumen. 



