PALM AND SOLE IMPREISSIONS. 397 



board or table^ placing upon it a little of the ink, and then rolling it 

 down with the roller until the paper is coated with a uniform thin 

 layer of ink. The best results are obtained when this is thin enough 

 to appear of a dull green ^color rather than black, and the usual diffi- 

 culty lies rather in using too much than too little ink. The hand or 

 foot to be printed is then laid upon the inked surface, pressed a little, 

 especially at the places which are naturally raised above the paper, and 

 then removed and laid in the same way upon a clean sheet of paper, 

 pressing the parts as in the first instance. Care must be taken not to 

 slip the hand or foot sideways at any time, as this would blur the lines ; 

 a similar condition may be caused by too great pressure, and thus when 

 the feet are taken the subject should be seated, allowing the foot to be 

 manipulated by a second operator. The inking surface should be 

 freshly rolled before each new impression, and when a number are 

 taken at one time, a little ink must be occasionally added and rolled 

 down. If mimeograph ink is not available, ordinary printer's ink will 

 do almost as well, and both sorts may be readily removed from the skin 

 by the use of a little turpentine or benzine, or even by soap and warm 

 water. 



After a collection of imprints has been made, the next procedure is 

 the interpretation, that is, the tracing out of certain definite lines 

 which mark the course of the ridges and define the patterns. As the 

 palm presents simpler conditions than does the sole and is much the 

 best for purposes of instruction, we will begin with a good average print 

 like that given in Fig. 1, using a sharp-pointed pencil, and, when neces- 

 sary, a reading glass of low power. At the base of each of the four 

 fingers there will be seen a triangular area composed of transverse 

 ridges, so intruded into the palm that it parts for some little distance 

 the ridges which belong more definitely to the palm itself. These are 

 the four digital areas, and at their apices are found points from which 

 the ridges radiate in three directions, two bounding digital areas and 

 one traversing more or less of the palm. These four points or triradii 

 (equivalent to Galton's 'deltas') are the starting points of the system 

 and may be termed the four digital triradii, numbered 1-4, beginning 

 at the inner or thumb side. The lines bounding the digital areas art3 

 the eigM digital lines, numbered from 1-8, and the four other lines 

 which proceed from the triradii and cross the palm are the four main 

 lines. These latter, designated by the letters A-D, are of primary 

 importance and furnish by their course the first or 'primary formulce 

 by which the palms are classified. These lines are established by fol- 

 lowing the direction of the ridges to whatever point they may lead, and 

 are best traced along a certain definite ridge, although, in places where 

 a ridge that is being followed breaks or forks, the line should be con- 

 tinued by means of an adjacent ridge, or by taking the general direc- /^^^^^i 



