we use iodoform gauze, which ought to contain not less than 20 per cent. of iodoform powder. It is made by rubbing the powder into gauze or muslin which has been dehydrated and sterilised. If nothing

but iodoform is used, the gauze is apt to part with its iodoform, and therefore some surgeons add glycerine. This fixes the iodoform, and renders the gauze soft and supple.

The following is the prescription of the late von Billroth,1 who was an enthusiastic advocate of iodoform-Iodoform, 50 grms.; glycerine, 50 grms.; alcohol (95 per cent.), 400 grms. Ten metres of gauze is uniformly impregnated with iodoform by pulverising the crystals in a mortar with the glycerine, and then adding the alcohol.

Iodoform emulsion for injection into sinuses or abscess cavities was made by Lord Lister by adding 1 part of iodoform to 10 parts of glycerine. This is improved, I think, by the addition of 1 part of ether and 2 of alcohol. But, as might be expected, such a popular remedy as iodoform is applied in a variety of ways.2

"Introduction to the Antiseptic Treatment of Wounds, according to the method in use in Professor Billroth's Clinic," by V. von Hacker, translated by Kilkelly, London, 1891, p. 42. This small work is full of useful information.

These are given in the "Extra Pharmacopoeia," Martindale and Westcott, 7th edition, p. 239 et seq.

Generally speaking, all the mixtures should be fresh. I have given up using a made-up mixture of iodoform collodion, because, as I have already said, it often decomposes, and develops pungent and acrid vapours.

PART IV.

CHAPTER XV.

SURGICAL TECHNICS.

WE may now begin to apply the foregoing to surgical practice. Our task is the exclusion of bacteria from wounds, and we have seen the means at our disposal for this purpose. It is not enough to pretend to keep out the harmful bacteria from wounds, whilst

To begin

allowing the so-called harmless to enter. with, it is not known which are harmless and which are harmful. Next, a method which is so defective as to admit one kind cannot keep out the other. The presence of any kind of bacterium in a wound proves that the method of treatment has failed.

We have now to apply our knowledge of disinfectants and antiseptics to-(a) The preparation of the surgeon and his helpers; (b) the preparation of the patient; (c) the preparation of the instruments and materials used at the operation; (d) to the operation; (c) to the treatment of the wound.