c 



Plate V. Experiments on the diffusion of phosphatase during use of the 

 Gomori-Takamatsu technique. Figure A, guinea-pig kidney superimposed 

 on inert section of guinea-pig liver, incubated 1280 minutes. Note that the 

 staining artefact on the inert section extends seven or more cell diameters 

 from the opaque active section. Figure B, photograph of liver section. 

 This was an inert section, upon which an active kidney section was super- 

 imposed, in buffer, for 2 days. Then the active section was removed, and 

 the previously inert section incubated for 1280 minutes, with the result 

 shown in the figure. All the blackening shown represents phosphatase 

 activity. Since the active section was removed prior to incubation, the 

 factor which had diffused from the active to the inert section must be 

 either phosphatase or phosphatase activator. Figure C, intrinsic phos- 

 phatase of guinea-pig liver: incubation time 1280 minutes. The phospha- 

 tase intrinsic to the liver sections of Figs. A and B was destroyed. Com- 

 parison of the three figures shows that the artefact phosphatase has a 

 different distribution from the intrinsic phosphatase. 



