362 AN ADDRESS ON 



mauve-coloured powder, the dyed cyanide, as supplied by Messrs. Morson, of 

 Southampton Row. For charging gauze it is diffused with pestle and mortar 

 in I to 20 solution of carbolic acid in the proportion of about 30 grs. to a pint ; 

 and the gauze, which must be of thoroughly absorbent quality, is drawn, in 

 a thickness of about eight layers, through the liquid, which is conveniently 

 placed in a trough having a bar near its lower part, beneath which the gauze is 

 made to pass, care being taken that the liquid is kept perpetually stirred to 

 prevent precipitation of the salt. The gauze is then hung up to dry at the 

 temperature of the air. The carbolic lotion is used in preference to water, both 

 because the powder is very much more easily diffused in it and because it is 

 desirable that any dirty material which the gauze may happen to contain may 

 be sterilized. A very cheap kind of carbolic acid will answer, and the solution 

 that drains from the gauze when it is hung up may be used again for the same 

 purpose. It thus scarcely adds to the expense of the preparation. 



This is a very simple process. For a whole year I prepared my own gauze, for 

 use in hospital as well as in private practice, before I had satisfied myself com- 

 pletely as to its value. For hospital use I would advise that the gauze should 

 be prepared in the institution, so as to save the manufacturer's charges. In that 

 case it may be taken down and wrapped in macintosh when only partly dry, 

 avoiding the trouble to the nurses in moistening it. 



Gauze may also be easily charged at a few minutes' notice for emergency in 

 private practice. I have here a 6-yd. piece of unprepared absorbent gauze folded 

 lengthwise in eight layers. I soak this thoroughly with i to 20 carbolic lotion, 

 and dust some of the powder roughly over one surface with a pepper-box. I then 

 roll it together, and kneading it for a minute or two with the fingers, produce, as 

 you see, a sufficiently uniform diffusion of the salt throughout the mass, as indi- 

 cated by the colour.^ If this were done by a nurse before the commencement 

 of an operation, and the wet gauze w^ere wrapped in a folded sheet to absorb 

 redundant moisture, it would be ready for use when required. A 6-yd. piece 

 would be an ample dressing for many cases. Now I see by the amount that has 

 gone from the pepper-box that not more than one-fifth of an ounce has been 

 used, and as Messrs. Morson supply the dyed cyanide at 20s. per lb., this implies 

 a cost of only 3^., so that it cannot be regarded as expensive.^ If you have no 



his kindness in ascertaining for me the chemical composition of rosalane. It is used in quantity equal to 

 •J per cent, of the weight of the double cyanide, and is appUed in watery solution, in which the salt, after 

 being freed from excess of cyanide of mercury by repeated washing, but before it has been dried, is 

 thoroughly diffused by stirring. The salt as it precipitates carries the dye down with it, and is after- 

 wards dried at a moderate temperature. 



^ A pair of leather gloves may be worn to avoid staining of the hands, or the dye may be washed 

 from the fingers with spirit of wine. 



"^ I found on weighing this piece of gauze when it was dry that it was needlessly heavily charged, 



