112 ON THE CATGUT LIGATURE 



away from all wounds to which they are applied in that clinique. They count 

 the ligatures as they put them on, and invariably see them all before the case 

 is done with. The catgut has been over-prepared. 



It is by means of chromic acid, however, that I have at length arrived at 

 a result which appears to satisfy all our conditions. But, before speaking of 

 the new method, I wish to say a few words more with regard to the old. To 

 what is it that it owes its virtue ? In this bottle is some catgut which has been 

 nearly ten months in our old preparing liquid — namely, one part of carbolic 

 acid which has been liquefied by means of water, to five parts of olive oil. In 

 this other vessel again we have catgut which has been the same length of time 

 in a solution of carbolic acid in water. Water will only take up about one- 

 twentieth part of its weight of carbolic acid ; but the effect produced upon the 

 catgut by the watery solution is very much greater than that brought about 

 by the four times stronger oily solution. In the former case, as you can see, 

 the catgut is almost black, a sort of purple black ; while the other is compara- 

 tively pale, very little altered from its original colour. This circumstance shows 

 two things. In the first place the effect of the watery solution of carbolic acid 

 upon the catgut explains the efficacy of the water in our old method. It is the 

 watery solution of carbolic acid in the liquid of the old method that is the effec- 

 tive agent. But in the second place we see that, when the watery solution is 

 mixed with oil, the fact that it is so mixed limits and checks its operation. If 

 catgut is kept in the watery solution only, there seems to be no limit to the 

 degree of continuous preparation of the gut — so that it becomes more and more 

 dark in colour, and more and more difficult of absorption b\^ the tissues. It is 

 otherwise when the watery solution is blended with the oil. Though the process 

 does go on for many months, there is a time when it comes to a standstill. 

 You need not fear that catgut prepared by the old plan is ever over-prepared. 

 There is a specimen on the table, which, at the end of twelve years, is as limp, 

 after steeping for a while in blood-serum, as it would have been at the end of 

 a single year. Therefore, we possess in the carbolic oil a means of checking 

 any mode of preparation that we may adopt, keeping it from that time forward 

 not materially further prepared ; while at the same time the large proportion 

 of the carbolic acid to the oil (i to 5) ensures the catgut being maintained 

 perfectly aseptic. 



The method of preparation which I have now the honour to bring before 

 you is the following. I dissolve one part of chromic acid in 4,000 parts of dis- 

 tilled water, and add to the solution 200 parts of pure carbolic acid, or absolute 

 phenol. In other words, I use a i to 20 watery solution of carbolic acid ; only 

 that the carbolic acid is dissolved, not in pure water, but in an exceedingly 



