By means of a correct metachromatic staining technique, the distribution of chondroitin sulphate in cartilage during inflammatory conditions has been described. The results support the following conclusions:
Preceding the actual inflammatory changes, a decrease in the content of chondroitin sulphate was ascertained. Most of the ester sulphate is lost when the inflammatory changes become established. The observed depletion of chondroit. in sulphate is probably effected by an alkaline depolymerization and disintegration of the molecule in question. Among different contributing factors, the alkaline hydrogen-ion concentration in inflammation seems to be of prime importance for the interpretation of the observations. The disintegration of the ester sulphate seems to be a prerequisite for the propagation of the inflammatory process in cartilage, and this in part explains the "resistance" of cartilage.