14° ELEMENTS OF APPLIED MICROSCOPY. 



yield values from which the deviations of the writer are 

 rarely great. Composite photographs of signatures, etc., 

 are important aids in work of this sort. In the second 

 place, more minute differences exist which can be detected 

 only under the compound microscope. These are of three 

 magnitudes. First, any long lines show certain varia- 

 tions of direction whose number and nature vary with 

 the writer. Second, much finer fluctuations occur, visible 

 only under the compound microscope, in the shape of 

 vertical deviations from side to side and changes in 

 width due to periodic changes in the pressure of the pen- 

 point. Third, on one or both margins of the line are 

 still more minute lateral serrations. These vertical and 

 lateral variations are both illustrated in Fig. 52. They 

 are, of course, influenced more or less by paper and 

 writing utensils and by the physical and mental condi- 

 tion of the writer; yet the size, position, and number of 

 the waves, swellings, and notches are so related to the 

 nervous organization of the writer, and differ so markedly 

 with different individuals, as to yield important aid in 

 the identification of handwriting. 



REFERENCES. 



Babcock, J. F. The Medico-Legal Examination of Blood and 

 other Stains, Hairs, and Fibres. New York, 1894. 



Frazer, p. Bibliotecs, or the Study of Documents. Phila- 

 delphia, 1901. 



Galton, F. Finger Prints. London, 1892. 



Galton, F. Finger-print Directories. London, 1895. 



RoscoE, H. E. Spectrum Analysis. London, 1870. 



Taylor, A. S. A Manual of Medical Jurisprudence. New 

 York and Philadelphia, 1897. 



Wood, E. S., Withatjs and Becker. Medical Jurisprudence, 

 Forensic Medicine and Toxicology. New York, 1894. 



