Surgery is a fine art that has reached a high degree of development in the treatment of facts, about which good surgeons are generally right.

A great deal of noise is made over surgeons' occasional mistakes, which are advertised by their detractors, but we hear little of their steady and almost constant success.

Medicine, on the other hand, must very often proceed by guesswork; but for that very reason it covers up its defects more anxiously, and is more inclined to talk loudly of its victories.

Every great physician admits that a good deal of his science is psychological; and psychology deals with the unknown, or with what is only partially knowable.

A mathematician may smile and answer that 'infinity' is much more than partially 'unknowable,' but that, by using it, the differential calculus gives results of most amazing accuracy, and is such a simple affair that, if its mere name did not inspire terror, any fourth-form schoolboy could easily be made to understand it, and even taught to use it.