ON THE CATGUT LIGATURE 117 



Now, if we examine catgut in the process of diminution in the hving body, 

 we find that it may be affected in one of two ways. If it has not been properly 

 prepared, the substance of the catgut becomes converted, in the course of a very 

 few days, into a soft pultaceous mass, which, when we examine it by a micro- 

 scope, we see consists of remains of the old cellular tissue of the submucous 

 coat, with the interstices among the fibres filled with cells of new formation. 

 The catgut tissue is infiltrated with young growing cells, and it is obvious it is 

 this infiltration which is the cause of the softening. But, on the other hand, 

 if the catgut is properly prepared, instead of being infiltrated by the cells of 

 new formation, it is only superficially eroded. In this stitch (Fig. i) of catgut 

 prepared by the new method, removed from a wound thirteen days after its 

 introduction, you have a good example of this important fact. You will see 

 that, at the part which was among the tissues, there remains a very slender 

 residue of the catgut, all the rest having gone ; but that slender residue was 

 pretty tough, and remained translucent, showing not even a superficial infiltra- 

 tion ; in short, having exactly the characters that we desire for catgut for the 

 ligature of an artery in its continuity, namely, that it shall not disappear too 

 rapidly, and that till the last, even though reduced in dimensions, it shall retain 

 some degree of its original firmness and tenacity. We know that antiseptic 

 treatment has shown that a piece of dead bone may be absorbed, provided it 

 be not putrid : the granulations that overlap it superficially may, so to speak, 

 erode it. It is not necessary for us now to consider how that is effected ; but 

 certainly, in some way or other, the granulations do what mere steeping in serum, 

 whether putrid or non-putrid, never would do. Never, I believe, would the 

 bone be dissolved by the serum ; and just as a non-putrid sequestrum is served 

 by the tissues, so is a well-prepared specimen of catgut ; it is superficially eroded. 

 I have here a stitch that I removed to-day from a wound made ten da^'s ago — 

 a wound made for stretching the anterior crural nerve, which, as well as the 

 sciatic, was subjected to that treatment, in an aggravated case of sciatica. 

 You may see that, as yet, it shows no signs of erosion. We know by experience 

 that, if it were left three or four more days, we should probably find it eroded, 

 as the former specimen indicates ; but until nearly a fortnight has elapsed 

 erosion does not begin. It then proceeds gradually, and, therefore, tlie thicker 

 the catgut the longer is the time required for its complete removal. \\'o may 

 fairly consider that from a fortnight to three weeks is long enough for the 

 persistence of a ligature upon an arterv in its continuity. [Three days later 

 I removed two remaining stitches in the case last referred to, and found 

 both of tliem slightly eroded superficially.] 



1 have brought with me this evening a preparation of the carotid artery 



