slowly and accurately how, by means of a single slip of paper
bearing the penciled name "Sabbatto Gizzi, P.O. Box 239,
Lambertville, N.J.," he had run down the unknown murderer of
an unknown Italian stabbed to death in the park's shrubbery.

Petrosino's physical characteristics were so pronounced
that he was probably as widely, if not more widely, known
than any other Italian in New York. He was short and heavy,
with enormous shoulders and a bull neck, on which was
placed a great round head like a summer squash. His face was
pock-marked, and he talked with a deliberation that was due
to his desire for accuracy, but which at times might have
been suspected to arise from some other cause. He rarely
smiled and went methodically about his business, which was to
drive the Italian criminals out of the city and country. Of
course, being a marked man in more senses than one, it was
practically impossible to disguise himself, and, accordingly,
he had to rely upon his own investigations and detective
powers, supplemented by the efforts of the trained men in the
Italian branch, many of whom are detectives of a high order of
ability. If the life of Petrosino were to be written, it
would be a book unique in the history of criminology and
crime, for this man was probably the only great detective of
the world to find his career in a foreign country amid
criminals of his own race.

I have instanced Petrosino as an example of a police detective
of a very unusual type, but I have known several other men on
the New York Police Force of real genius in their own
particular lines of work. One of these is an Irishman who