Angela worked hard, and made such progress that before the two years of her noviciate were over Doctor Pieri said openly that she was the best surgical nurse in the hospital, and one of the best for ordinary illnesses, considering how limited her experience had been. The nursing of wounds is more mechanical than the nursing of a fever, for instance, and can be sooner learned by a beginner, where the surgeon himself is always at hand. On the other hand, the value of surgical nursing depends on relative perfection of detail and rigorous adherence to the set rules of prophylaxis, whereas other nursing often requires that judgment which only experience can give. 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. What we call the soul may be infinite or infinitesimal, or finite, or it may be the Hegelian Nothing, which is Pure Being under another name; whatever it is, our acquaintance with it is not knowledge of it, since whatever we can find out about it is based on the Criticism exercised by Pure Reason and not on experience; and the information which Pure Reason gives us about the soul is not categorical but antinomial; and by the time medicine gets into these transcendental regions, consciously or unconsciously, it ceases to be of much practical use in curing 'pernicious anaemia' or any similarly obscure disease.