NOTE ON THE PREPARATION OF CATGUT 

 FOR SURGICAL PURPOSES 



[British Medical Journal, 1908, vol. i, p. 12^.] 



Catgut used for ligatures or sutures in surgery should fulfil various con- 

 ditions. It should, after soaking in water or blood-serum, be strong enough to 

 bear any strain to which it may be subjected, and should hold perfectly when 

 tied in a reef-knot. It must not be so rigid as it lies among the tissues as to 

 have any chance of working its way out by mechanical irritation. Nor should 

 it be too quickly absorbed, but should be consumed so slowly by the cells of 

 the new tissue that grows at its expense that, in case of the ligature of an arterial 

 trunk in its continuity, it may serve sufficiently long as a support for the sub- 

 stitute living thread in its embryonic condition. At the same time, it is essential 

 that the catgut be securely aseptic when applied. 



Of the various substances which I have tried for the preparation of catgut, 

 that which has, with one exception, most nearly approached the ideal is sulphate 

 of chromium. The one exception is secure asepsis of the gut substance, this 

 salt being utterly untrustworthy as a germicide ; this defect is easily remedied 

 by the addition of a little corrosive sublimate, the powerful germicidal action of 

 which is not prevented by the chromium sulphate. 



I was at one time discouraged from using chromium sulphate by finding 

 that it varied extremely in quality according to the manufacturer who supplied 

 it. Thus one sample got from a well-known firm proved quite insoluble in 

 water.^ But a perfectly satisfactory result was obtained by adding solution of 

 sulphurous acid (Pharm. Brit.) to solution of chromic acid until the rich orange- 

 brown of the latter has passed through grass-green to the pure blue of chromium 

 sulphate. When this has occurred no more should be added, since free sulphurous 

 acid produces a precipitate with bichloride of mercury, and would thus, in 

 proportion to its amount, withdraw the germicide from solution when the two 

 liquids are mixed. In order to make quite sure that no free sulphurous acid is 

 present, it is well to keep a few drops of the chromic acid liquid in reserve, and 

 add them when the blue colour has appeared, so as to restore the green tint. 



' I learn from Messrs. Morson (of Elm Street, Gray's Inn Road), who have devoted a great deal of 

 attention to this salt, that its most suitable form requires very great care in its preparation in order 

 to avoid variation in its composition, and also that it is extremely hygroscopic, so that, unless it is very 

 carefully preserved, water in variable amount becomes associated with it, ajiothcr cause of unccnainty 

 in its composition. 



