Theoretical explanations are always abstract and diffuse in their development. My method may at first appear difficult and complicated, which, indeed, pretended savans have chosen to affirm. Nevertheless it is not so, and in order to comprehend it, it is sufficient to study it. It is with this as with everything else, to know it is necessary to study and to practice. The beautiful art which I am about to explain to agriculturists is most easily acquired. Its technical dictionary is composed only of certain words, of which the readers should, first of all, know perfectly the precise signification. These words are _Escutcheons, Epis or Tufts ascending_, and _Epis or Tufts_ descending. After he knows perfectly the different forms and the importance of these characteristic signs, he will know the whole subject as well as I do myself. The Epis or Tuft, as one will see, participates with the escutcheon in the distinction of the orders—it multiplies the sub-divisions. It seems at the same time to complicate my method and to render it less accessible; but I have not felt myself at liberty to omit it, since it has an incontestible and important value. If, among certain animals, the form and extent of characteristic signs are not exactly those of the drawings, but a sort of intermediate between the characteristic signs of two classes, he who applies the method should approximate them to the drawing of the classification from which they differ the least, and from that deduce the probable value. To render my work perfectly clear, I had to enter into the developments very much in detail. Nevertheless, so extensive are these details that I believe I have given neither too many nor too few, and have confined myself simply within the limits of the possible, the indispensible and the useful. And now, whoever my opponents may be, I proclaim boldly and without fear, that the escutcheon is the only incontestible characteristic sign that can enable one to discern, by simple inspection, the aptitude for milk production of each animal. All animals of the bovine species in good state of health, to which no accident has happened, and whose escutcheons are of the first orders of each class, will manifest always, and without exception, as much for the production of milk as for generative ability. Beauty of form, to my thinking, represents but an ideal, and although one ought to take it into consideration, it is a simple accessory without value of its own, when the question is that of the production of milk. May I have been able to justify by this work the fruit of the experience of my whole life, the honor done me by many agricultural societies in admitting me to their membership, and by the government which has shared the expense of this new edition, with the twofold purpose of encouraging my efforts and facilitating the propagation of my method. GUENON’S METHOD OF JUDGING OF THE VALUE OF STOCK.