DIGESTION OF LIGATURES. 101 



the clot, and acting very like some of the forms of bacteria. 

 Thus, the clot is digested and removed, and when it is gone 

 any surplus new tissue that may have been formed during the 

 activity of the process suffers the same fate. It is, in turn, 

 digested and removed. 



DIGESTION OF LIGATURES. 



Of late it has become quite the fashion, among surgeons, to 

 use ligatures, for deep sutures, made of digestible material, 

 such as catgut, animal membrane, etc. These are left in, and 

 it is said they are absorbed. They must be dissolved first. 

 They do not dissolve in ordinary liquids, nor do they dissolve 

 in pus, or upon pus-forming surfaces, or in the usual plasma 

 of the tissues. The surgeon is very careful that they be so 

 prepared that they shall not. He is careful that they are not 

 easy of digestion. The " International Encyclopedia of Sur- 

 gery " says: " The spontaneous solution of catgut ligatures, 

 when set in wounds, is caused, not by any chemical solution 

 of their structure, nor by any process of organization which 

 they undergo, but by the invasion of leucocytes, under the 

 operation of which they vanish, while new tissue takes their 

 place; but, if they be over-prepared (i. e. y rendered too diffi- 

 cult of digestion), this change does not occur, and they act like 

 foreign bodies in general." 



Here we see that the ligature does not dissolve in the ordi- 

 nary plasma of the tissue, if properly prepared. The tissue 

 must approach closely a physiological condition, it must throw 

 out certain cells which invade it, as it would be invaded by 

 bacteria if they had the opportunity. These cells must throw 

 out their special ferment for the occasion, to digest the catgut 

 and make room for themselves, as would be done by bacteria ; 

 and thus they continue to dissolve out the foreign digestible 

 substance and take its place, stimulated to this action by its 



