“But what else can we do?” said Rentland, doubtfully. “Modern practical psychology gives a dozen possible ways for proving the knowledge of the man higher up in this corporation crime,” Trant answered, “and I am considering which is the most practicable. Only tell me,” he demanded suddenly; “Mr. Welter I have heard is one of the rich men of New York who make it a fad to give largely to universities and other institutions; can you tell me with what ones he may be most closely interested?” “I have heard,” Rentland replied, “that he is one of the patrons of the Stuyvesant School of Science. It is probably the most fashionably patroned institution in New York; and Welter’s name, I know, figures with it in the newspapers.” “Nothing could be better!” Trant exclaimed. “Kuno Schmalz has his psychological laboratory there. I see my way now, Rentland; and you will hear from me early in the afternoon. But keep away from the docks!” He turned and left the astonished customs officers abruptly. Half an hour later the young psychologist sent in his card to Professor Schmalz in the laboratory of the Stuyvesant School of Science. The German, broad-faced, spectacled, beaming, himself came to the laboratory door. “Is it Mr. Trant—the young, apt pupil of my old friend, Dr. Reiland?” he boomed, admiringly. “Ach! luck is good to Reiland! For twenty years I, too, have shown them in the laboratory how fear, guilt, every emotion causes in the body reactions which can be measured. But do they apply it? Pouf! No! it remains to them all impractical, academic, because I have only nincompoops in my classes!” “Professor Schmalz,” said Trant, following him into the laboratory, and glancing from one to another of the delicate instruments with keen interest, “tell me along what line you are now working.” “Ach! I have been for a year now experimenting with the plethysmograph and the pneumograph. I make a taste, I make a smell, or I make a noise to excite feeling in the subject; and I read by the plethysmograph that the volume of blood in the hand decreases under the emotions and that the pulse quickens; and by the pneumograph I read that the breathing is easier or quicker, depending on whether the emotions are pleasant or unpleasant. I have performed this year more than two thousand of those experiments.” “Good! I have a problem in which you can be of the very greatest use to me; and the plethysmograph and the pneumograph will serve my purpose as well as any other instruments in the laboratory. For no matter how hardened a man may be, no matter how impossible it may have become to detect his feelings in his face or bearing, he cannot prevent the volume of blood in his hand from decreasing, and his breathing from becoming different, under the influence of emotions of fear or guilt. By the way, professor, is Mr. Welter familiar with these experiments of yours?”