78 ON THE ANTISEPTIC SYSTEM 



ment for fluid, by brushing over the antiseptic lac with a weak solution of gutta- 

 percha in bisulphide of carbon, which, rapidly evaporating, leaves a coating 

 of microscopic thinness, yet effectual for preventing adhesion. We have now 

 given this lac dressing a sufficient trial in wounds and abscesses to entitle me 

 to recommend it with confidence.^ 



For an antiseptic dressing that is intended to be changed from time to 

 time, perfect absence of adhesiveness is a most valuable property ; not only 

 because it permits all discharge to escape beneath it into the porous material 

 placed outside to absorb it, but because it avoids traction upon any deeper 

 dressing or upon the skin during the process of withdrawing it, with the con- 

 comitant risk of regurgitation of air or liquid charged with living putrefactive 

 organisms. 



But for the permanent dressing in compound fracture this complete want 

 of adhesiveness is the converse of what we desire. Here, the material employed, 

 being designed to form part of the scab, should stick to the skin or to anything 

 else that lies beneath it. The lac prepared as above described may, however, 

 be readily made suitable for this purpose, by rubbing off the film of gutta-percha 

 by firm friction with a dry cloth, and then brushing the surface over with liquid 

 carbolic acid. It then, at once, assumes a sufficient degree of adhesiveness. 



In order to ensure healing without suppuration, it is requisite, as we have 

 seen, not only to prevent the spreading of putrefaction into the wound, but 

 also to protect the raw surface from perpetual stimulation by the carbolic acid. 

 In the mode of dressing, above described, in which the putty was employed, 

 the latter object was attained by means of layers of lint forming a crust too 

 thick to be penetrated by the acid supplied externally ; and the same plan 

 would, no doubt, succeed as well with the lac. But to trust to the mere thick- 

 ness of a penetrable crust is not altogether satisfactor}^ It would clearly be 

 better, if possible, to protect the exposed tissues from the stimulating antiseptic 

 in the lac by a layer of some substance chemically impermeable to carbolic acid. 

 A metallic plate possesses this property ; and in its more flexible forms, such 

 as thin block-tin or sheet-lead, it seems likely, at least in ordinary cases, to 



^ This plaster is supplied at a very moderate price by the New Apothecaries' Company, Glassford 

 Street, Glasgow, to whom I am much indebted for the interest and pains they have taken in bringing 

 it to perfection. The following is the mode of its manufacture : Take of shellac, 3 parts ; crystalhzed 

 carbolic acid, i part. Heat the lac with about a third of the carbolic acid over a slow fire till the lac 

 is completely melted ; then remove from the fire and add the remainder of the acid, and stir briskly 

 till the ingredients are thoroughly mixed. Strain through musUn, and pour into the machine for spread- 

 ing plaster ; and, when the Uquid has thickened by cooUng to a degree ascertained by experience, spread 

 to the thickness of about one-fiftieth of an inch. Afterwards, brush the surface of the plaster lightly 

 with a solution of gutta-percha in about thirty parts of bisulpliide of carbon. When the sulphide has 

 all evaporated, the plaster may be piled in suitable lengths in a tin box without adhering, or rolled up 

 and kept in a canister. 



