proved completely successful as to what may be termed its commercial object, but that, though it concerned only a humble worm, it laid the foundation of an entirely new system and method of research into the nature and causes of a large class of diseases in man and the higher animals, of which we are now only beginning to see the important issues.
Among the most immediately productive of its results may be accounted the "antiseptic surgery" of Professor Lister, of which the principle is the careful exclusion of living bacteria and other germs alike from the natural internal cavities of the body and from such as are formed by disease, whenever these may be laid open by accident or may have to be opened surgically. This exclusion is effected by the judicious use of carbolic acid, which kills the germs without doing any mischief to the patient; and the saving of lives, of limbs, and of severe suffering, already brought about by this method, constitutes in itself a glorious triumph alike to the scientific elaborator of the germ-doctrine and to the scientific surgeon by whom it has been thus applied.
A far wider range of study, however, soon opened itself. The revival by Dr. Farr of the doctrine of zymosis (fermentation), long ago suggested by the sagacity of Robert Boyle, and practically taken up in the middle of the last century by Sir John Pringle (the most scientific physician of his time), as the expression of the effect produced in the blood by the introduction of a specific poison (such as that of small-pox, measles, scarlatina, cholera, typhus, etc.), had naturally directed the attention of thoughtful men to the question (often previously raised speculatively) whether these specific poisons are not really organic germs, each kind of which, a real contagium vivum, when sown in the circulating fluid, produces a definite zymosis of its own, in the course of which the poison is reproduced with large increase, exactly after the manner of yeast in a fermenting wort. Pasteur's success brought this question to the front as one not to talk about but to work at, the lead being taken, I believe, by M. Chauveau, the distinguished Professor of Medicine at Lyons, but other investigators (among them our own Professor Burdon-Sanderson) followed closely in his wake. Pasteur's own attention seems at that time to have been chiefly directed to what may be termed the pathology of beer, wine, and vinegar, and to the fight he had still to maintain with the advocates of abiogenesis. I shall not stop to describe the valuable improvements he has introduced into the manufacture of alcoholic and acetous liquors, with a view of preventing those injurious fermentations which often interfere with the normal processes, and sometimes ruin their results, but shall keep to the object I have specially in view, the exposition of those more recent contributions to "preventive medicine," which constitute him the greatest public benefactor of his time.