Similarly for the nose, of which three main varieties are recognised, according as the line of the back is concave, rectilinear, or convex. Each of these three principal classes is divided into three divisions according to the direction of the base line--ascending, horizontal, or descending. The degree of concavity or convexity of the line of the nose, as well as the degree in which the base line descends or mounts, is indicated in very simple fashion by putting the term denoting the form into brackets or underlining it. Thus a moderately concave-backed nose is expressed by the abbreviation "cav."; if the concavity is very slightly marked by (cav.); and, if very accentuated, by _cav._ Noses of which the line is very sinuous or arched are denoted by the abbreviations "s" and "a." A nose described as _cav._ (s) would have a very strongly-marked concavity and be slightly sinuous, whereas (cav.) _s_ would denote a nose but slightly concave, but with a very sinuous outline. The form of the root of the nose is also indicated in similar fashion to the back and base. So much for the shape of the nose. Its dimensions relatively to the face, its width, length, and degree of projection, are also indicated, for it is evident that size is quite independent of shape. The degree of inclination of the forehead is another feature that is noted, as well as the general aspect of the complexion, colour of hair and eyes, and anything about the face that is in the least abnormal. The entire course of instruction in "word-portraits" extends over thirty lessons of two hours each. At the end of the course an examination is held, in which the pupil must acquit himself honourably in the practical tests imposed upon him, if he wishes to obtain the coveted certificate, without which he can now hope for no promotion. Several hundred persons are assembled; with the exception of a few privileged strangers, almost all are connected directly or indirectly with the various services of the police administration. M. Bertillon or his principal lieutenant, M. Payen, hands a slip of paper to the candidate, containing some such brief indications as the following: "R--cav. (deq.) cav. × 1·62. O. 1878." "Pick out the person to whom this refers," adds the examiner. In an incredibly short space of time one of the audience finds himself "under arrest." The figures 1·62, it may be said, denote the person's height; "O" stands for orange-coloured eyes; and 1878 denotes, approximately, the year of birth--that is, that he is now about twenty-six years of age. [Illustration: DIFFERENT TYPES OF EARS FROM THE CLASSIFICATION-BOOK.]