There are many patterns, which, when analysed into their composing elements, present analogies to artistic designs, a view which is no mere personal fad, but has been affirmed with enthusiasm by many artists in designs to whom I have pointed out those figures. Here are a few, by way of illustrating this point (space will not permit of more). Those figures are from real human finger-prints rendered diagrammatically. This is the first step, then, to catch with the eye the pattern or design; give it a class name, and you have at once established some practical basis of classification in finger-prints. Then it is possible to frame some kind of catalogue for reference arranged like a dictionary with its sub-alphabetic order, in an almost infinite series. The initial difficulty is generally that which arises from want of skill in printing, which technical points will be considered subsequently. A soft and flexible substance like the ridges in human fingers does not always yield an exactly similar impression in two successive moments, under varying conditions of temperature, fatigue, and the like. Nor does the analogy of mathematical diagrams always fitly apply in such a case. Even in steel engravings and fine etchings, as the connoisseur well knows, the degree of intensity of the pressure and other conditions will modify to some slight extent the resulting imprint, but what I wish to emphasize is, that if the original pattern had any value at all resulting from its complexity as a pattern, the variation in printing as now done officially by experienced police officials will not impair much its value as evidence of personal identity in a court of law. Even the amateur will soon, after a little practice with good materials, attain a very fair amount of clearness and uniformity in his imprints. CHAPTER IV SOME BIOLOGICAL QUESTIONS IN DACTYLOGRAPHY.