Aqueous extracts of autolyzed blood samples from various spp. were chromatographed on paper strips and analyzed by bio-autography. Lactobacillus leichmannii 4797 was used as the seed organism. A normal butanol-water system was used in making the chromatograms. Liver extract and vit. B12 were used as reference standards. Bioautographs of extracts from autolyzed blood samples of the turtle, chicken and turkey blood were almost identical with the bioautograph of liver extract. There was a stationary spot at the top which corresponded to vit. Bl2 and 3 spots below. If the above-mentioned blood samples were autoclaved at pH 7 and bioautographed, the stationary spot was the only spot observed on the bioautograph. The latter indicates that desoxyribonucleases and nucleosidases in the blood accounted for the liberation of the desoxyribosides in blood from spp. with nucleated erythrocytes. Aqueous extracts from autolyzed blood samples from the turtle, chicken and turkey, when autoclaved at pH 12, gave a bioautograph showing the 3 desoxyribosides only. Bioautographs of aqueous extracts from autolyzed blood samples from the cow, pig and sheep showed a B12 spot but not the desoxyribosides.