changes in the absorption spectrum of the dye, indicative of the presence of macromolecules, were observed. This was true for soils which had a total organic carbon content as low as 0.2 percent. Concentrated extracts from some of the soils, which exhibited new absorption peaks in the 535- and 650-mμ regions of the spectrum, were analyzed for macromolecules by conventional laboratory methods. Macromolecules were isolated and amino acids and monosaccharides were obtained when the macromolecules were hydrolyzed, indicating that the macromolecules present in the soils were proteins and polysaccharides. This is in agreement with the results obtained by the dye test and strongly indicates that the method will be very useful for the detection of macromolecular species which are characteristic of all living material as we know it.
Figure 11 shows three absorption maxima. The first, at 505 mμ, is the region of normal dye absorption. The others, at 575 mμ and 648 mμ, are absorption bands due to the interaction of the dye with a 0.002-percent solution of oxidized ribonuclease.
Figure 11.—Three absorption maxima in the J-band region.
