INTRODUCTION XXX1X 
Lister subsequently gave much time and thought to the discovery of the best 
methods of preparing the catgut ligature so as to meet the various conditions 
which were required, and his latest contribution to the subject was in fact pub- 
lished so recently as the 18th of January, 1908.1 The raw catgut as obtained 
from the shops was unsatisfactory, for the ligature as soon as it becarne soaked 
with fluid, and especially with serum, swelled up, and the knots became untied : 
further, it was absorbed too rapidly, a most serious drawback. The chief points 
to which he paid attention in the preparation of catgut suitable for general 
surgical use were the breaking strain, the solidity and permanence of the knot, 
the pliability of the material, and the rapidity of its absorption in the tissues ; 
the papers in which he described the different methods devised for attaining 
these objects are reprinted in the second volume. At the present time, in the 
preparation of catgut attention is directed chiefly to its sterilization, without 
special reference to the other essentials on which so much stress was laid by 
Lister, but it may be doubted whether this is wise, and whether any better 
material than Lister’s sulpho-chromic catgut has been introduced. 
The adoption of absorbent dressings and absorbable ligatures marked a 
distinct stage in the development of antiseptic surgery ; by simplifying the 
technique and rendering the results surer in the hands of other surgeons, it 
greatly contributed to bring about the general adoption of the system, and 
paved the way for the extraordinary extension of the field of surgery which the 
next quarter of a century was to witness. 
At about the same time the metallic suture ceased to be the sole method 
of closing the wound, giving place to more convenient stitches of silk. In 1870° 
Lister gave an interesting account of the methods he employed in stitching up 
a wound, especially in those cases in which a portion of the skin had been removed, 
and where, therefore, there was considerable tension at the edges of the wound. 
The silk was rendered aseptic by being impregnated with a mixture of carbolic 
acid and melted bees-wax, and was kept in a five per cent. solution of carbolic 
acid until required. Catgut was also used in suitable cases for stitches, silver 
wire was employed where much tension existed, and silkworm gut and horsehair 
were utilized especially in septic cases. Later, waxed silk was replaced for 
most purposes by ordinary Chinese twist, rendered aseptic by having been steeped 
in I to 20 watery solution of carbolic acid. 
It was at about this period also that Lister began to make use of the india- 
rubber drainage-tubes devised by Chassaignac early in the century for carrying 
off pus. Though no pus was formed in aseptic wounds, yet a considerable flow of 
blood and serum followed immediately upon the infliction of the wound, however 
1- Vol. 0, p. 119. * Vol. i p. 139. 
