“I am not saying anything about that.” “I see. Your idea is to set a trap for me. Well, let’s see if you can catch me.” Laughing softly as though he had heard a good joke the chemist took out a microscope and put the blood-spotted paper under its powerful lens. As he spent only a comparatively few minutes in scrutinizing the spots of blood, it was fair to presume that their characteristics were so distinctly defined as to give him little trouble in determining from what animal they had come. Nick Carter had watched him throughout, and a grim smile flickered about his lips as he saw the look of certainty and satisfaction that came over the professor’s face. When the latter finally looked up, the detective inquiringly, said: “Well?” The professor laughed softly, then said: “If your purpose here is to try me and see if you can trip me up, I’ll tell you what I will do.” “What?” “I’ll make you a wager of a box of good cigars that I am able to tell you the first time what blood this is.” “I am not here to try you, but to ascertain through you what this blood came from.” “Is that true?” “Yes.” “And you do not know whence this blood came?” To acknowledge entire ignorance would not be politic, so Nick said: “I am not prepared to answer that question further than to say that I may have well-founded suspicions.” “Do you think that it is a goat’s blood?” “You may as well tell me what your own opinion is, or you will not get anything out of me.” “Well, that blood came from--a chicken.” “You are sure of that?” “I am.” “Would you swear to it?” “With great willingness.” “How can you be so positive?” “Easily enough. The red corpuscles in the blood are different in everything that lives and breathes, and as a rule this difference is so great that there can be no mistake between corpuscles of man and beast, or between any two beasts. As between human blood and that of fowls the difference is very distinct, so in this case there can by no possibility be a doubt. Singularly enough the closest approach to similarity is between the red corpuscles of a human being and the hog.” “Will you now kindly seal up that piece of paper and preserve it for use in case of necessity?” “I will.” The blood-spotted paper was inclosed in a stout wrapper and then fastened with sealing wax, the latter being impressed with a seal belonging to the professor and another that the detective improvised on the moment, but which he could swear to. This last was necessary, as if it should ever get into court the paper would have to be sworn to as being the one examined this day. Had it borne only one seal, it is evident that the wrapper might be opened and a substitution made. A double seal, of which each possessed one, made it equally evident that the wrapper could not be tampered with. On leaving the professor’s, Nick Carter went to his office.