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all be said to have been based on one cardinal principle—viz., an attempt to exclude air from the wound. To some the air seemed to produce evil consequences by its coldness—to some by its dryness—to others by a kind of stimulating property; but to Lister's mind it occurred that the evil depended not so much on the air itself as on the impurities it contained. Among the floating particles were unquestionably those germs which the biologists of all schools were so busily trying to exclude from their solutions and infusions when discussing the origin of life; and these he endeavoured to exclude from his operations by the employment of germicides and cotton-wool. It is not for me here, as a physician addressing physicians, to attempt to estimate the value of his results. The hypothesis is one that claims the earnest consideration of surgeons, and the practice which it suggests numbers now a large number of adherents. I need only add one word of caution in weighing the arguments on one side or the other. If these germs abound, as we are led to believe they do abound, and if their exclusion be a matter of such delicate manipulation that it has stirred up the strife of two opposing parties of scientific enquirers for a long series of years, it is unquestionable that the precautions necessary for their exclusion or death must be most minute. True conclusions as to their influence on the divided
