detectives to antagonize the newspapers. Scotland Yard
found that out in the Crippen case."

"My idea of the thing, Jameson," continued Kennedy, "is that the
professor of criminal science ought to work with, not against, the
regular detectives. They're all right. They're indispensable, of course.
Half the secret of success nowadays is organisation. The professor of
criminal science should be merely what the professor in a technical
school often is--a sort of consulting engineer. For instance, I believe
that organisation plus science would go far toward clearing up that Wall
Street case I see you are reading."

I expressed some doubt as to whether the regular police were enlightened
enough to take that view of it.

"Some of them are," he replied. "Yesterday the chief of police in a
Western city sent a man East to see me about the Price murder: you know
the case?"

Indeed I did. A wealthy banker of the town had been murdered on the
road to the golf club, no one knew why or by whom. Every clue had proved
fruitless, and the list of suspects was itself so long and so impossible
as to seem most discouraging.

"He sent me a piece of a torn handkerchief with a deep blood-stain on
it," pursued Kennedy. "He said it clearly didn't belong to the murdered
man, that it indicated that the murderer had himself been wounded in the
tussle, but as yet it had proved utterly valueless as a clue. Would I
see what I could make of it?

"After his man had told me the story I had a feeling that the murder was
committed by either a Sicilian labourer on the links or a negro waiter
at the club. Well, to make a short story shorter, I decided to test the
blood-stain. Probably you didn't know it, but the Carnegie Institution
has just published a minute, careful, and dry study of the blood of
human beings and of animals.

"In fact, they have been able to reclassify the whole animal kingdom
on this basis, and have made some most surprising additions to our
knowledge of evolution. Now I don't propose to bore you with the details
of the tests, but one of the things they showed was that the blood of a
certain branch of the human race gives a reaction much like the blood of
a certain group of monkeys, the chimpanzees, while the blood of another
branch gives a reaction like that of the gorilla. Of course there's lots
more to it, but this is all that need concern us now.

"I tried the tests. The blood on the handkerchief conformed strictly
to the la