ON THE CATGUT LIGATURE 115 



strength two pounds out of thirteen. I think that is reaUy aU that can be 

 desired. 



[A few days after the dehvery of this address I made some experiments 

 regarding the strength of the new gut after longer periods of immersion, using 

 the serum which I had before employed for the purpose, and which, being 

 derived from blood taken from a cow with antiseptic precautions, remained still 

 perfectly sweet. I first tried the specimen of gut twelve years old, prepared 

 by the old method, a portion of which I exhibited at the meeting steeped in 

 serum. It is comparatively slender gut, having little more than half the thick- 

 ness of the chromic gut with which I before experimented, the average diameter 

 being if -hundredths of an inch. Two trials of it in the dry state gave 5 lb. 9 oz. 

 as the average breaking strain ; and two other pieces, after steeping half an 

 hour in the warm serum, broke at 3 lb. 14 oz. In other words, this especially 

 well-seasoned sample of what the old method could provide was deprived by 

 warm serum of about one-third of its strength in half an hour. I next tested 

 a piece of gut prepared three months ago by the new method, similar in thick- 

 ness to the other, viz. having an average diameter of if -hundredths of an inch. 

 Four trials with it in the dry state gave an average breaking strain of 6 lb. 15 oz. 

 I then placed in the warm serum three other pieces of the same hank, after 

 measuring their diameters. One of these pieces, with diameter if-hundredths 

 of an inch, tested after it had been one hour in the serum, broke at a strain of 

 5 lb. 13 oz. Another piece, which when dry measured decidedly less in diameter 

 than the first, was tried after being fourteen hours and a half in the serum, 

 when it also broke at 5 lb. 13 oz. A third piece, just if -hundredths of an inch 

 in diameter when dry, was left in the warm serum for twenty-four hours, at the 

 end of which time it showed a breaking strain of 5 lb. io|- oz. Thus the new 

 gut continued as strong, or nearly so, at the end of a day in the serum as it had 

 been after the lapse of an hour, and lost in the serum onh' about one-seventh 

 of its full strength in the dry state, a result corresponding ver\' closely with 

 that obtained in the former experiment with the thicker chromic gut after 

 forty minutes' immersion. At the same time, the new gut being considerably 

 stronger to start with than that prepared by the old method, its strength, after 

 steeping for twenty-four hours in warm serum, was greater than that of the old 

 kind in the dry state.] 



The only remaining condition to be considered regarding the new catgut, 

 is its suitable behaviour among the tissues. Before describing tliis. I must say 

 a few words regarding the manner in which catgut is absorbed. It has been 

 said of late by various persons that the catgut is dissolved by the serum. 1 must 

 confess that this is entircl}' cuntrary to my own experience. 1 ha\c ahead)' 



