Abstract
The cytochemical Millon reaction has been studied with test protein systems and with several plant and animal tissues. Absorption curves of the Millon chromophores have been analyzed and compared with natural ultraviolet protein absorption. The findings indicate the validity of applying the Millon reaction as a quantitative cytochemical method in studies of the nucleoprotein complexes of cells, but only when proper corrections for non-specific light loss and other variables have been applied. Under these conditions, a roughly linear relationship was found between natural ultraviolet protein absorption at 280 mµ and the intensity of the Millon chromophore at 500 mµ. A scheme of intermediate products and competing reactions coincident to formation of Millon chromophores has been proposed, based on changes in absorption spectra during color development in test protein systems.