292 



SCIENCE. 



[N. S. Vol. XIY. No. 347. 



of probabilities has been used in any rigid way. 

 The author's experience leads him to adopt a 

 difference of Ibfo between the average and the 

 disputed signature as ground for suspicion. 

 Differences of 5 or even 10^ are not uncommon 

 in genuine specimens. But differences of 15 fo 

 are uncommon, and, especially if repeated, are 

 suspicious. The expert's decision must often 

 rest on rather weak foundation as judged from 

 a scientific standpoint, and the more so since he 

 often has but half a dozen specimens from which 

 to determine his average. The work of Mr. 

 Frazer is very suggestive of what might be done 

 in the study of handwriting. An extensive 

 study of the variability of the individual, and of 

 the differences between different individuals, as 

 regards these ratios, angles, and other details, 

 would show how sharply individualized they 

 are, and furnish a scientific basis for the expert. 

 Another method of the author is the micro- 

 scopic examination of the margins of the strokes. 

 Under a magnification of 120 diameters, or even 

 much less, a pen or pencil stroke is seen to have 

 irregular edges ; it is full of serrations of dif- 

 ferent sizes, the smaller superposed on the 

 larger. There are usually more of them in one 

 margin than in the other, depending on the 

 position of the pen and other peculiarities of 

 the writer. Whether they are completely in- 

 dividual, it would be premature to say, but 

 they can at least be often used to distinguish 

 between the writing of two persons. With the 

 cooperation of Professor Witmer, the author 

 has made micro-photographs and camera lucida 

 tracings of these wavy margins, and inclines to 

 regard some of them as i^ecords of the minute, 

 normal tremor of the hands, produced by 

 fluctuation in the nerve currents that control 

 the muscles. Machine-ruled lines, though not 

 free from irregular margins, showed fewer 

 serrations than lines made by hand. There- 

 viewer is much inclined to doubt this interpre- 

 tation of the wavy margins, since he finds the 

 serrations more marked on rough than on 

 smooth paper, whereas the friction of the 

 rovigh paper would tend to conceal the tremor. 

 The rate, too, at which the serrations are pro- 

 duced is not approximately constant, as that 

 of the tremor is, namely, at 8-15 pulses per 

 second ; a fast stroke and a slow show about 



the same number of serrations per millimeter 

 and those in the fast stroke must have been 

 made, in one line measured, at about the rate 

 of 480 per second. Many of the irregularities 

 are probably due to the texture of the paper, 

 and others to vibrations of the pen. Yet one's 

 manner of holding the pen might give rise to 

 characteristic forms of margin. 



Still other chapters of the book treat of the 

 chemical and y)hysical tests for inks, of tests 

 for erasure and other tampering, of tests 

 for 'guided hands,' and of other problems in- 

 cidental to the detection of forgery. There 

 are several excellent plates. 



E. S. WOODWORTH. 



Taxidermy, Comprising the Skinning, Stuffing and 

 Mounting of Birds, Mammals and Fish. With 

 numerous engravings and diagrams. Edited 

 by Paul IST. Hasltjck. London, Paris, New 

 York and Melbourne, Cassell & Company. 

 1901. 16mo. Pp. 160. 



Within the last ten years at least three ad- 

 mirable books on taxidermy have been brought 

 out in the United States, and any new work on 

 the subject should either bring forward some 

 new and improved process of preserving ani- 

 mals, or at least present the most approved 

 methods in a clear and detailed manner. The 

 little book under consideration does neither ; 

 the methods described in its pages are the old 

 ones, and not always the best of those, while 

 the amount of space given to each group of ani- 

 mals is so limited that the descriptions are nec- 

 essarily brief, while there is nothing whatever 

 on the mounting of large mammals, although 

 this is seldom acquired from books alone. 



However, the book is intended for the ama- 

 teur who wishes to preserve some trophy of the 

 chase rather than for any one who really intends 

 to master the art of taxidermy, and there are di- 

 rections for making screens, polishing horns, 

 tanning skins, and doing various bits of taxi- 

 dermic fancy work. The small size of the book 

 enables it be to readily put in the pocket, and, 

 as it takes but little room, it might readily be 

 carried to seashore or country on the chance that 

 it might be desired to save some bird, mammal 

 or fish, or make a pair of wings into a screen. 



F. A. L. 



