The identification of an individual solely by means of his handwriting is always liable to lead to a miscarriage of justice, for even in the cases of the closest resemblance between two writings there can be no certainty on this point. In the following pages I have attempted to point out under what varying conditions handwriting may show alterations and thus lead to wrong conclusions. In the making of handwriting heredity plays a very important part, just as it does in the characteristic gait and the little mannerisms which are peculiar to each individual. In addition to this, the writing may be modified by the results of training and other external influences. It is obviously not possible to determine from which ancestors all the features in one's handwriting are inherited, just as it is impossible to trace the origin of certain obviously inherited traits of character. At the same time, instances in which close resemblances may be noticed between the handwriting of a man and that of his father and grandfather will occur to everyone. Thus a particular slope in the direction of the writing or a mode of looping the letters or of forming certain words may be passed on from generation to generation. [Illustration: HEREDITY IN HANDWRITING] A remarkable fact in this connection is that there is frequently a tendency for a son to inherit certain characteristics in the father's writing and for the daughters' writing to resemble more closely that of their mother than that of their father. The examples shown in the figure illustrate this tendency. The words were all written by members of one family, the first two lines being those of the father and the mother. The third, fifth, eighth and ninth lines were written by their daughters, and the fourth, sixth and seventh lines by their sons. It will be noticed among other points of resemblance that the bold characteristic looping of the letter L in the mother's handwriting is reproduced more or less closely in the writing of all the daughters, while the sons form the same letter with a small loop, as in the word written by their father. The angles at which the different words are written also show the effect of this "parallel heredity," as it might be termed. While possessing such points of resemblance obviously inherited from the parents' handwriting, the writing of each of the children also shows characteristics of its own that distinguish it from the writings of the others--characteristics partly inherited from other ancestors and partly the result of environment. So close, however, is the resemblance between the handwriting of the father and of the eldest son that on more than one occasion one has been mistaken for the other by other members of the family.