Comparative investigations were carried out on series of rat liver preparations which were tested for the specificity of the saliva test in the histochemical demonstration of glycogen. The results were as follows the saliva test suffices only with the specific polysaccharide reaction according to Bauer as a control. It is not enough, however, with the unspecific PAS reaction. A ferment working specifically on glycogen is absolutely necessary as a control, such as the purified diastase.