It must be clearly understood, therefore, by the public to whom this translation is addressed, that the advantage they can get from its perusal is not the immediate power to apply the method themselves, but a general idea of a new science. The theory of evolution is now common property, but no lay person for that reason dreams of carrying on biological experiments in his own pantry. He knows it requires a laboratory and apparatus, and, above all, training and skill. Morelli, rightly understood, has conferred upon culture the immense service of bringing art into line with modern ideas of human evolution. He has conquered a new field for science. His general theory is easily grasped by people trained in modern habits of scientific thought, and these same people would be the first to understand that such a delicate instrument as his method is not a thing to put into the hands of the tyro. Unfortunately, people of so-called "culture," the public to whom this volume is addressed, are the class least permeated with modern scientific notions, and there is reason to fear, therefore, that many of them may take advantage of the translation of a book they were too lazy or too ignorant to read in the original, to set up as independent "connoisseurs," and thereby continue that confusion of tongues which has brought art criticism into such well-deserved contempt.