“Decidedly convincing,” said Nick, with a look of satisfaction on his strong, clean-cut face. “There is no question as to the reliability of a microscopic examination of particles of blood, if made by a person thoroughly informed on the subject. I have, as you know, made an exhaustive study of it.” “I am aware of that, Nick, of course.” “The blood of no two creatures is precisely alike,” Nick continued. “Under the microscope, and with proper tests, that of two human beings, even, presents certain distinct differences, often by a small margin, of course, but nevertheless clearly distinct.” “So I have read,” Chick nodded. “It is perfectly easy to tell the blood of a white man from that of a negro, that of a lower animal from that of a man, or that of one animal from that of another, as well as to determine the animal from which it comes. That is because the blood of each crystallizes in invariable definite forms.” “Gee, that’s some study!” Patsy remarked sententiously. “The existence of disease is also apparent under the microscope and with proper tests,” Nick went on. “Science immediately recognizes one from another. Thin, anæmic blood presents a distinctly different appearance from the strong, rich blood of a vigorous person. That’s the very point, in connection with this case, without further elaboration on the subject.” “These bloodstains tell the story, do they?” questioned Patsy. “They tell part of it, Patsy, with absolute certainty,” Nick replied. “The blood on my handkerchief, which we know positively came from Matilda Lancey, is very rich with red corpuscles, obviously that of a strong, healthy woman.” “Tilly Lancey looked it,” Chick observed. “The blood on these articles, however, shows a distinct difference,” said Nick. “There is a decided lack of the red corpuscles. It is thin and anæmic. It is human blood, nevertheless, and it came from a woman. The proportion of red corpuscles in the stains on each of these articles, with the exception of my handkerchief, plainly shows that same anæmic condition.” “In other words, then, the stains on the jimmy and on Gordon’s garments are not caused by the blood of Tilly Lancey,” said Chick. “They are not,” Nick replied. “I am absolutely sure of that. It is distinctly different from the blood on my handkerchief. That on these other articles came from a rather frail and delicate woman, very probably with a tendency to consumption.” “Gee whiz! that suggests something to me, chief,” said Patsy, drawing nearer the table. “What is that?” “I have frequently seen Tilly Lancey with the woman referred to by Phelan as her running mate, the woman named Cora Cavendish. She is just that type, chief, slender and noticeably pale, barring the rouge with which she hides it.” “That is suggestive, indeed, Patsy,” Nick agreed. “But I already suspected that Cora Cavendish had a hand in this job.” “Why so, chief?”