Page:The Green Bag (1889–1914), Volume 07.pdf/84

 Detecting Human Blood.

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DETECTING HUMAN BLOOD.1 ANOTHER safeguard has been thrown out against murder. Daniel Webster's saying that " murder will out " gathers more and more truth as time progresses. When he first made it, it was epigrammatic and effective, but it was inaccurate. It has been since time began less true that murder will out than it has been that burglary, or chicken stealing, or forgery will out. The mur derer knows that the penalty of his crime is death. No man likes to pay that penalty. Every man will go to the most extravagant extreme to avoid paying it. When a man's life instead of merely his liberty depends on carefully planning a crime beforehand and carefully hiding it afterward, he will make greater efforts toward both these ends than he would in any other circumstances. It is true that about as large a proportion of mur der mysteries as of burglar mysteries are solved, but the proportion is not quite as large, and it should be remembered that the forces of law and order exert twenty times as much energy toward tracing a murderer as they do toward tracing a burglar. Jus tice often miscarries for lack of proper sci entific aid. In one case in a great American city the whole thing went wrong, and the accused man — of whose guilt scarcely any one had doubt — was not even indicted, because sci ence had no means of differentiating be tween the blood of human beings and the blood of animals. It was clear that the man had had every opportunity for committing the crime, and indirect evidence of a motive for it existed, but when the matter was placed before the grand jury the only direct evidence that he had been concerned in it was his possession of a knife stained with blood. He acknowledged that the knife was his and that it was he who had stained it with blood, but that it was the blood of a 1 Edward Marshall, in the Galveston Xews.

pet dog, upon whose broken leg he proved that he had performed a rude operation, and although all the scientific knowledge in the city was brought to bear upon the subject, not one learned man was found who was certain enough of his learning to swear the life of the accused away by testifying posi tively that the blood was human and not animal. In fact, this point has been one which has baffled scientific criminology ever since criminology became scientific. The minds of the greatest scientists in the world have been devoted to this problem, but have always failed to find a solution for it. Rec ords exist of cases in which this very point puzzled prosecutions as long as a century ago. It remained, in fact, for a New York scientist to make this discovery less than three weeks ago, and in this article is given positively the first hint of it which has been heard by the public. The scientist is Dr. Cyrus Edson. He is already famous as a sanitationist, and through this expert knowledge has risen to the high position of president of the New York State Board of Health and commis sioner of health in New York City. He is an investigating scientist. His wide reputa tion and his prominent public position have caused him to be frequently called as an ex pert in murder cases. Often the value of his testimony has hung upon the differentia tion between the blood of animals and the blood of man. Notwithstanding that he had made a deep study of the subject, and knew that a well-defined and important difference existed, his means of defining that difference in his own mind and before the eyes of a jury was so delicate and so likely to be af fected even unto inaccuracy by outside and slight conditions, that he never felt justif1ed in giving positive testimony on this point. He was in the same position as that in which other scientists have found themselves. He