Abstract
The shortcomings of Gomori's method for the histochemical demonstration of the enzyme phosphamidase lie in the need for a long incubation period and for the distinction between reaction products due to enzyme action and those due to spontaneous hydrolysis of the substrate. A modification of his method is suggested which permits reduction of the incubation period to about a fourth and eliminates the need to distinguish between reaction products of different origin in brief incubations.
The suggested procedure is free from erratic failures to obtain positive results. As tested for brain, the overall pictures of enzyme distribution are uniformly reproducible. Variability of results is reduced to the occasional occurrence of small areas in which no precipitate has formed. It is felt that with these changes the method is ready to be subjected to a more advanced stage of investigation, as for instance the preservation of the enzyme content during fixing, dry-freezing, etc.