Test: A Leaf Which Destroyed Reacting Power A point of scientific interest, and of importance in criminal investigation, came out in the Sikh murder case continued at H. M. Police court last Friday afternoon. It may be remembered that in their search for the missing man, Arjan Singh, the police discovered traces of blood on the ground at the rear of No. 59 Vu Yuen Road and when tests were applied by the Public Health Department this was found not to be human blood.
An explanayjon was forthcoming yesterday upon evidence _being given by Dr. R..A. P. Hill, Pathologist. Dr. Hill stated that he applied the precipitation test to the sample of blood supplied to him by the police, and the result was a negative test for human blood, a re-test on the following day giving the same result. This sample was on a rape leaf taken from the field at the back of No. 59 Vu Yuen Road. Witness then made a further test, using his own blood for the purpose. It was put{ on another rape leaf taken from this field, exposed for 32 hours at room temperature, and tested in the same way, and again the result was negative for human blood.
Mr. E. T. Maitland—Meantng that you were not human?
Witness—Meaning that it did rob give the reaction of human blood. It shows that exposure on a leaf of this particular plant destroys, or may destroy, the reacting power of human blood.
Mr. Maitland—Is that.a well-known fact?
Witnes—It appears not to be generally known. So far as I know, it is unknown. I have found no reference to it in any book.
Asked if the precipitant test ever failed, witness said there were certain well-known cases of a false positive result, but he could find no record of any cause of a false negative. except the presence of strong chemical reagents, or a sample many years old.
Text read from the printed page and cleaned; old type leaves the occasional error.