Another method is to incise the abscess, cleanse the cavity with gauze, irrigate with Carrel-Dakin solution and pack with gauze smeared with the dilute non-toxic B.I.P.P. (bismuth and iodoform 2 parts, vaseline 12 parts, hard paraffin, sufficient to give the consistence of butter).  The wound is closed with “bipped” silk sutures; one of these—­the “waiting suture”—­is left loose to permit of withdrawal of the gauze after forty-eight hours; the waiting suture is then tied, and delayed primary union is thus effected.

When the skin over the abscess is red, thin, and about to give way, as is frequently the case when the abscess is situated in the subcutaneous cellular tissue, any skin which is undermined and infected with tubercle should be removed with the scissors at the same time that the abscess is dealt with.

In abscesses treated by the open method, when the cavity has become lined with healthy granulations, it may be closed by secondary suture, or, if the granulating surface is flush with the skin, healing may be hastened by skin-grafting.

If the tuberculous abscess has burst and left a sinus, this is apt to persist because of the presence of tuberculous tissue in its wall, and of superadded pyogenic infection, or because it serves as an avenue for the escape of discharge from a focus of tubercle in a bone or a lymph gland.

[Illustration:  FIG. 35.—­Tuberculous Sinus injected through its opening in the forearm with bismuth paste.

(Mr. Pirie Watson’s case—­Radiogram by Dr. Hope Fowler.)]

The treatment varies with the conditions present, and must include measures directed to the lesion from which the sinus has originated.  The extent and direction of any given sinus may be demonstrated by the use of the probe, or, more accurately, by injecting the sinus with a paste consisting of white vaseline containing 10 to 30 per cent. of bismuth subcarbonate, and following its track with the X-rays (Fig. 35).

It was found by Beck of Chicago that the injection of bismuth paste is frequently followed by healing of the sinus, and that, if one injection fails to bring about a cure, repeating the injection every second day may be successful.  Some caution must be observed in this treatment, as symptoms of poisoning have been observed to follow its use.  If they manifest themselves, an injection of warm olive oil should be given; the oil, left in for twelve hours or so, forms an emulsion with the bismuth, which can be withdrawn by aspiration.  Iodoform suspended in glycerin may be employed in a similar manner.  When these and other non-operative measures fail, and the whole track of the sinus is accessible, it should be laid open, scraped, and packed with bismuth or iodoform gauze until it heals from the bottom.

The tuberculous ulcer is described in the chapter on ulcers.

CHAPTER IX

SYPHILIS