e 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 makes a specialty of get-rich-quick men, oil and
mining stock operators, wire-tappers and their kin, and who knows the
antecedents and history of most of them better than any other man in the
country. He is ready to take the part of either a "sucker" or a fellow
crook, as the exigencies of the case may demand.

There are detectives--real ones--on the police force of all the great
cities of the world to-day, most of them specialists, a few of them
geniuses capable of undertaking the ferreting out of any sort of
mystery, but the last are rare. The police detective usually lacks the
training, education, and social experience to make him effective in
dealing with the class of elite criminals who make high society their
field. Yet, of course, it is this class of crooks who most excite our
interest and who fill the pages of popular detective fiction.

The headquarters man has no time nor inclination to follow the sporting
duchess and the fictitious earl who accompanies her in their picturesque
wanderings around the world. He is busy inside the confines of his own
country. Parents or children may disappear, but the mere seeking of
oblivion on their part is no crime and does not concern him except by
special dispensation on the part of his superiors. Divorced couples may
steal their own children back and forth, royalties may inadvertently
involve