Fresh blood samples of known group were smeared on cloth, paper and metal implements, and allowed to stand for various intervals of time. The dried blood-stains were then again tested. When putrefaction of the blood samples set in before they dried, as many as 14 out of 18 wrong groups were obtained. It is of importance to note that not only were agglutinogen or agglutinin destroyed during the drying or ageing of the blood stains, but in some instances changes occurred which yielded reactions simulating those of some particular agglutinogen.
The authors strongly advise against the use of blood-grouping of partially decomposed (and contaminated) blood stains, since our experiments definitely prove that 100 per cent correct results cannot be obtained.