Douglas Blackburn,
The Detection of Forgery
“ It is these unconscious hand-gestures and mechanical tricks of style that the handwriting expert learns to distinguish and recognise,—the unconsidered trifles that the writer has probably never devoted a minute's thought to, and which come upon him as a surprise when they are pointed out to him. Their detection is rendered the more easy when one knows what to look for from the fact that they are, unlike gestures and tricks of voice, permanent. ”
