96 MICROSCOPIC TECHNIQUES 



(acetate, phosphate, glycine, und carbonate buffers have been 

 employed) in the respective proportion of 50:10 or 5:20. 

 5% Potassium Acetate Solution. 



PROCEDURE 



1 . Prepare frozen sections directly from very fresh tissue. 



2. Repeat step 2 in the preceding cytochrome oxidase method, 

 but wash sections with physiological saline instead of water. 



3. Nuclei may be stained with lithium carmine. 



4. Examine under a microscope with the section covered with 

 potassium acetate soln. Permanent preparations cannot be made. 



Result. The blue or blue-violet color is also produced in this case. 



?9 



Loele Method for "a-Naphthol Oxidase 



SPECIAL REAGENTS 



Naphthol Reagent. Add 10% potassium hydroxide dropwise to a 

 little a-naphthol in a test tube until the a-naphthol is dissolved. 

 Add 200 ml. distilled water, and after 24 hr. the reagent may be 

 used for about 3 weeks. 



PROCEDURE 



1. Prepare frozen sections of formalin-fixed tissue. 



2. Treat sections with the a-naphthol reagent and observe effect 

 under the microscope within a few minutes. 



Result. Violet or black granules which soon disappear are sup- 

 posed to be indicative of a-naphthol oxidase. 



SUCCINIC DEHYDROGENASE 



Semenoff ( 1935) gave a method for the localization of succinic 

 dehydrogenase in tissue sections which depends on the reduction of 

 methylene blue. The diffusibility of the dye should obviate the 

 possibility of good localizations by this method. 



Semenoff Method for Succinic Dehydrogenase 



SPECIAL REAGENTS 



Substrate Medium. To 2 ml. 0.05% methylene blue add 2 ml. 



