I'MIULIVAL IllJllXI.t. 709 



and many others, they are not always to be preferred to other methods 

 of treatment. 



2. Topical Applications. — Topical applications have been for 

 centuries employed for the cure of hernia, Celsus having recommended 

 the use of sulphuric acid, which was resorted to at a later period by the 

 early hippiatrists ; and since 1833, when it was brought to notice by 

 Hertwig. it has been used in Germany, being applied to the tumour 

 every two or three days. The subcutaneous serous inliltration and the 

 plastic exudation in tbe hernial sac, drive the misplaced viscera into the 

 al>domen, and, in becoming absorbed afterwards, produce obliteration 

 of the cavity and its opening. Blisters act in the same way; and appli- 

 cations of alcohol, creosote water, and other agents, have been largely 

 resorted to. But Girax-d, D'Arboval, Benard, and Mignon have asserted 

 that these topical applications are very uncertain, and even dangerous, 

 as the irritation produced readily causes adhesion between the wall 

 of the sac and the organs it contained, and thus renders i^eduction im- 

 possible. 



But in 1848, Dayot, and more recently other veterinarians, had drawn 

 attention to the value of nitric acid cauterisation in umbilical hernia. 

 The acid is applied to the skin covering the tumour until at first an 

 eschar is formed, and, finally, detachment of the cutaneous hernial sac 

 is achieved. In order to efl'ect this, the hair is removed from the skin, 

 and by means of a spun-glass brush or cotton- wool fi.xed on a glass rod, 

 nitric acid of commerce is applied around the base of the tumour at 

 first ; then over the other part it is used in sufticient quantity, and with 

 friction, so as to destroy the skin and ensure its speedy mortification and 

 sloughing. Experience has proved that the more profound the dis- 

 organisation the more certain is the beneficial action. According to 

 Lafosse, it requires from 24 to 32 grammes of acid for a hernial tumour 

 the size of a fist ; and the friction, which ought to be as equable as 

 possible over the whole surface, should be continued for three to five 

 minutes — supposing the animal to be quiet and the rubbing not inter- 

 rupted. A smaller quantity of acid and less friction may be employed 

 to herniie which are not so considerable in volume, and are covered by 

 fine skin. When the animal has to be thrown and placed on its back, 

 the quantity of acid and amount of friction must also be diminished. 

 Dayot reconmiends that the application be repeated once or twice in 

 the hour, according to the thickness of the skin ; but it has been found 

 that one application is generally sufficient, fifteen days being allowed to 

 elapse in order to watch the result. If at the end of this time the skin 

 is not destroyed, the application may be repeated. 



The nitric acid produces a yellow eschar, which, if not dry on the first 

 day, soon becomes soft, unctuous to the touch, and easily destroyed. 

 With the formation of this eschar there is much swelling, either imme- 

 diately on the application of the acid, or soon after; in some cases there 

 is but little if any swelling. The tumefaction is due to the action of the 

 nitric acid on the subcutaneous connective tissue, which becomes infil- 

 trated, and causes a uniform pressure on the hernied mass ; this leads 

 to the latter being pushed into the abdomen and kept there as if by a 

 truss. The oedematous swelling established external to the tumour, is 

 oblong and depressed in the centre, in consequence of the diminished 

 elasticity of the central portion of the escharified skin ; in a few days it 

 is gradually absorbed and becomes more consistent, while the skin in 



