114 ON THE CATGUT LIGATURE 



may do it in different ways. For instance, he may take two large test-tubes, 

 one a little larger than the other, and he may wind the catgut on the smaller 

 tube, fixing one end by sealing-wax, winding it round, then bringing it up again, 

 and fixing the other end also with sealing wax at a higher level than the liquid 

 will reach, putting sufiicient liquid into the larger test-tube, and introducing 

 the smaller test-tube with the catgut wound round it, and containing a little 

 shot or other heavy material to keep it down in the liquid. After forty-eight 

 hours he takes out the smaller test-tube, and leaves it till the catgut is com- 

 pletely dry. I merely mention this as an illustration, and also as furnishing 

 a hint to some surgeons in private practice who may desire to prepare the catgut 

 themselves. Or a couple of gallipots, one larger than the other, will do just as 

 well. But, as I have already said, the principal uncoiling takes place during 

 drying ; and for all ordinary purposes a sufficiently good article is got by putting 

 the catgut loose into the liquid, and making it dry on the stretch, by tying the 

 ends of each hank to two fixed points in a room. 



In the dry state, catgut prepared by this method is as strong as need be. 

 As to strength in the condition after steeping in blood-serum, I confess it is 

 only this very day that I have obtained evidence that catgut thus prepared 

 is really all that we can desire in that respect. The catgut of the hank from 

 which this specimen w^as taken measured in the dry state 2f-hundredths of an 

 inch in diameter, and broke at 13 lb. 6 oz. I have found by experiment that 

 10 lb. is the utmost strain that my arms are able to put upon a cord. Thirteen 

 pounds six ounces, then, is amply sufiicient ; while, at the same time, the catgut 

 is not at all too large for going into the eye of an aneurysm-needle. Having 

 obtained, the other day, some fresh blood of a cow from the slaughter-house, 

 I took some of the serum to-day, and put two pieces of this same hank of catgut 

 in the serum, and placed it in a stoppered bottle in a warm box at a temperature 

 of 98° Fahr. After more than half an hour I tested the breaking strain (I 

 must not stop to explain how that is done^), and I found that the breaking 

 strain of the same catgut which in the dry state had broken at 13 lb. 6 oz. 

 was II lb. 4 oz. ; that is, though suppled by the serum, it had only lost in 



^ The mode of proceeding was as follows. A piece of steel, of horseshoe form, is suspended by 

 a ring on the middle of its convexity, so that the horns of the horseshoe are dependent ; these horns 

 being perforated for the reception of a cylindrical bolt of steel, which thus lies horizontally, and can 

 be removed at pleasure, A piece of the catgut having been tied in a double reef-knot, the bolt is partially 

 withdrawn, and is readjusted after the noose of the catgut has been slipped over it. Into the lower 

 part of the catgut-ring thus suspended is passed the upper end of a pot-hook, to the lower part of which 

 are attached weights approaching what the gut is likely to bear, and also an empty bag, into which 

 shot is poured till the cord gives way. The shot is weighed ; and the result, added to the other weights, 

 gives double the breaking strain of the gut ; for, as the cylindrical bolt works with perfect smoothness 

 in its bed, it adjusts itself so as to prevent inequality of strain in the two sides of the catgut-ring, which 

 thus take an exactly equal share in sustaining the weight. 



