XXV111 INTRODUCTION 
satisfied, but was always straining for something better, having ever in mind his 
one great ideal of making the conditions existing in an open identical with 
those in a subcutaneous wound. 
This activity took three great directions : (I) bacteriological work, especially 
in connexion with the germ theory of putrefaction ; (2) constant striving after 
improvements in the methods employed in carrying out the principle which he 
had laid down as essential in the treatment of wounds; and (3) improvements 
in the treatment of various diseases and injuries, rendered possible by the fact 
that operations had lost their greatest dangers. 
BACTERIOLOGICAL WORK 
In the early days Lister did a great deal of bacteriological work, partly 
in order to satisfy himself as to the accuracy of the theory on which he had 
based his system of treatment, and partly to test suggested alterations in his 
methods. Very little of this work has been published, indeed most of it was 
never intended for publication, but what he has written shows the impress of 
his genius. He repeated Pasteur’s experiments, especially that of the flask with 
the contorted neck, and he showed that the same results might be obtained by 
another method, namely by the use of glasses provided with loosely fitting glass 
covers." He also pointed out the importance of properly sterilizing by heat all 
vessels employed in these experiments, and he introduced the methods of dry 
sterilization which are still employed for this purpose.? He devised a flask for 
the storage of organic fluids and also methods of filling tubes and vessels from 
these flasks, which are most valuable when working with fluid media.® 
Perhaps his most important work in pure bacteriology was that on lactic 
fermentation. In that he obtained for the first time a pure cultivation of a 
single species of bacterium (Bacillus lactis), and he demonstrated that the 
lactic fermentation was due to the growth of this organism in milk. In this 
connexion he devised a plan of separating different kinds of bacteria from 
one another by repeated dilution which, though very laborious, remained 
practically the only satisfactory means of obtaining pure cultures till the 
introduction of Koch’s method of cultivation on solid media. 
Experiments were also made on the sterility of the natural fluids of the body, 
such as milk and urine, before they came into contact with the external air. 
A great deal of work was done in the way of testing new antiseptics and the 
value of different dressings, in fact almost every one of the later stages in his 
methods was tested in this way. Very interesting also is his work on the value of 
= Voli. p.. 270: “a Vola; (pez * Vol. ii, p. 55. 
