Master notes that his faculty of observation and facility
for deduction was due, in part, to systematic training.
He thoughtfully adds, "My
ancestors were country squires, who appear to have led
much the same life as is natural to their class. But,
nonetheless, my turn that way is in my veins, and
may have come with my grandmother, who was the sister
of Vernet, the French artist. Art in the blood is liable
to take the strangest forms."
it is that he turns his "art in the blood"
towards the arts and sciences of deduction. Among the
more prominent of these arts are Tracking, Handwriting
Analysis, Cryptography, Studies upon Paper & Watermarks,
and Tobaccana (which is analyzed elsewhere on this site).
addition, Holmes made a small study of opening locks
by nefarious means. In GREE,
the inspector notes "the clever way in which [Holmes]
had forced back the catch. With a nod to the criminal classes who might exploit such a a discussion, an extended treatment of lock-picking is excluded from this site.