divided vessels with either hemp or silk; these ligatures had to be cut long and left hanging out of the wound to be separated at a later date, usually about the tenth day after the operation. The separation was necessarily accompanied by ulceration and suppuration, and what is termed secondary haemorrhage was a frequent and much dreaded complication. Lister studied experimentally in animals the changes undergone by ligatures in aseptic wounds, and as a result of these studies, introduced catgut as a suitable substance for ligatures, as it was ultimately absorbed. The raw catgut was, however, unsuitable, and he devoted many years to experiments on catgut, in order to prepare it in such a manner that it should retain its firmness and at the same time be aseptic. His work on ligatures is a striking example of the successful use in surgery of knowledge obtained by preliminary experiments on animals. He also introduced many other improvements in technique, such as the simple expedient of elevating a limb prior to an operation on it, and so rendering it bloodless before the application of a tourniquet, and saving the patient an unnecessary loss of blood.
As a result of his main discoveries, all made in the course of a very few years, the practice of surgery underwent a complete revolution. In Lister's wards septic diseases did not occur, post-operative pyaemia, hospital gangrene, and tetanus disappeared, and erysipelas was rare, unless introduced. Occasionally wounds did not heal without suppuration, but even this was exceptional, and whenever it occurred, all the factors in the case were carefully investigated to ascertain the cause of the failure. Very soon his methods were applied to all kinds of surgical operations. The vanishing of septic diseases enlarged enormously the field of surgery, since operations formerly dreaded, owing to this risk, could now be carried out in safety. Lister himself introduced many new operations for the treatment of diseases and disabilities, that would have been quite impracticable without the assurance that the operation wound would heal with no septic complications. The modern development of surgery in relation to disease and injury of deep-seated organs in the chest, abdomen, &c., was only possible as the result of his discoveries, and it is probable that no man's work has had a greater influence on the progress of surgery; the saving of human life and suffering that he effected is incalculable.
Lister's work as a practical surgeon is sometimes apt to be overlooked owing to the magnitude of his work as a scientific investigator. He devised many new operations in various departments of surgery that would have made the reputation of a lesser man. Throughout his life he was improving his methods and especially the materials employed to render dressings antiseptic. During the last twenty years further modifications have been introduced, and the surgeon now uses heat more and chemical agents less, for the sterilization of instruments and dressings. Modern surgical technique is often termed aseptic rather than antiseptic; this, however, is not a modification of principle but only of method. The principles are the same as those inculcated by Lister, who might, had he liked, have used the term aseptic instead of antiseptic to describe his original method. Lister's methods did not meet with ready acceptance by the surgeons of this country. His own pupils adopted his system with enthusiasm, but the older surgeons were very slow in accepting it. Abroad it met with earlier and greater recognition, especially in France and Germany.
During his tenure of the chair of surgery at Glasgow, Lister was an unsuccessful candidate for the chair of surgery at Edinburgh in 1864, and for a similar chair at his old school, University College, London, in 1866. But in 1869 he became professor of clinical surgery at Edinburgh and remained there until he was invited to King's College, London, in 1877. On accepting this invitation he made the condition that he should bring with him his house-surgeon, (Sir) W. Watson Cheyne, a senior assistant (John Stewart), and two dressers (W. M. Dobie and James Altham), in order that his new methods might be carried out efficiently. Lister filled the chair of clinical surgery at King's College for fifteen years, and during the whole of this time was actively engaged in teaching and in pursuing his researches, besides practising as a surgeon and doing much public work. Thus he played an important part in securing modifications in certain proposed enactments restricting experiments on living animals. He was firmly convinced of the necessity of such experiments for the progress of medicine and surgery, and much of his own work was of this nature. He took an active part in founding (1891) the British Institute of Preventive Medicine on the lines of the Pasteur Institute in Paris, and became its first chairman. In 1897 its name was changed to the Jenner Institute and again in 1903 to the
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