The chemical evidence, however, went to prove that coagulation of the blood had not occurred until after it had come into contact with the knife, or, in other words, that the blade had been plunged into living blood.
Moreover it was stated by this witness that the blood could not have been that of an ox, pig or sheep, since the corpuscles were smaller than those of human blood, whereas the corpuscles of the blood upon the knife were of the same dimensions as those of human blood. The relative sizes of human corpuscles compared with those of the animals mentioned were stated to be as fifty-three to thirty-four in the case of the ox; as fifty-two to thirty-four in sheep’s blood; and as forty-five to thirty-four in pig’s blood.
The judge, in his summing up, made the following comments upon the evidence: “The witness had said that the blood upon the knife could not be the blood of an animal as stated by the prisoner, and took upon himself to say it could not be the blood of a dead animal; that it was living blood and that it was human blood; and he had shown them the marvellous powers of the modern microscope. At the same time, admitting the great advantages of science, they were coming to great niceties indeed, when they speculated upon things almost beyond perception, and he would advise the jury not to convict on this scientific speculation alone.”
The jury found the prisoner guilty upon evidence other than this “scientific speculation,” the novelty of which probably prevented the judge from accepting it as a demonstration of facts which might be verified or disproved.
The application of a remarkable discovery in physiological chemistry has now made it possible to determine whether a blood-stain consists of the blood of any particular kind of animal.
In 1898 it was discovered by Bordet that on injecting serum of cow’s milk into a small animal, such as a rabbit, which was then killed after a lapse of some weeks, the serum separated from its blood would produce a precipitate in cow’s milk.
This discovery was supplemented by Wassermann, who, in 1900, found that it was possible in this way to distinguish between the milk of different kinds of animals, and he suggested the name precipitines for these specific precipitating agents formed in the sera of animals.
Then Dr. von Rigler showed that the method might be employed to distinguish between the flesh of different kinds of animals.
GOAT’S HAIR