Abstract
The chemical specificity of the lead acetate reaction (17) has been improved by the use of ammonium acetate and other variants in the cytochemical technique. It has been possible to establish that inorganic phosphate is a normal component of the nucleolus.
Whether it is present only in the nucleoli, as suggested by the cytological specificity of the test, or whether it represents only a fraction of the total inorganic phosphate of the cell, remains to be proved.