"What is it?" I asked.
"Well, take the case before us. We have had no chance to finger-print that woman and what good would it do if we had? No one could recognize her that way until she was arrested or some means had been taken to get the prints again.
"But the portrait parle is scientific apprehension, the step that comes before scientific identification by finger-prints. It means giving the detective an actual portrait of the person he is sent after without burdening him with a photograph. As descriptions are now given, together with a photograph, a person is described as of such a weight, height, general appearance, and so on. A clever crook knows that. He knows how to change his appearance so that there are few even of the best detectives who can recognize him. This new system describes the features so that a man can carry them in his mind systematically, features that cannot be changed.
"Take the nose, for example," explained Kennedy. "There are only three kinds, as Bertillon calls them—convex, straight, and concave. A detective, we will say, is sent out after a man with a concave nose or, as in this case a woman with a straight nose. Thus he is freed from the necessity of taking a second glance at two-thirds of the women, roughly, that he meets—that is, theoretically. He passes by all with convex and concave noses.
"There are four classes of ears—triangular, square, oval, and round, as they may be called. Having narrowed his search to women with straight noses, the detective needs to concern himself with only one-fourth of the women with straight noses. Having come down to women with straight noses and, say, oval ears, he will eliminate all those that do not have the mouth, lips, chin, eyes, forehead, and so on that have been given him. Besides that, there are other striking differences in noses and ears that make his work much easier than you would imagine, once he has been trained to observe such things quickly."
"It sounds all right," I agreed haltingly.
"It is all right, too," he argued warmly. "The proof of it is its use in Paris and other cities abroad and the fact that it has been imported here to New York in the Police Department and has been used by the Government. I could tell you many interesting stories about how it has succeeded where photographs would have failed."
I had been reading over the description again and trying to apply it.
"For instance," Craig resumed thoughtfully. "I believe that this woman is a mulatto, but that is a long way from proving it. Still, I hope that by using the portrait parle and other things we may be able to draw the loose threads together into a net that will catch her—providing, of course, that she ought to be caught."
He had finished making copies of the portrait parle and had called for a cheque for the lunch.