6. Wash in distilled water. 7. Differentiate in glycerin ether until no more clouds of color come away and section is light blue. 8. Wash in distilled water. 9. 70 per cent alcohol for a few seconds; absolute 5-10 minutes; xylol; balsam. Protoplasm is gray-brown; bacteria dark-blue; background colorless. Zieler’s method is especially good for the staining of the glanders, typhoid and chancroid bacilli and the gonococcus. For Unna’s methylene-blue eosin and the modifications of the Romanowsky method see Pages 260 and 290 respectively. Pappenheim’s methyl-green-pyronin method is also recommended for the staining in sections of Gram-negative bacteria. Not Staining by Gram’s (Gram-negative). Gonococcus. Micrococcus melitensis. Meningococcus (in sections). Bacillus of bubonic plague. Bacillus of chancroid. Bacillus coli communis. Bacillus dysenteriæ. Bacillus of epidemic conjunctivitis (Koch-Weeks). Bacillus of influenza. Bacillus mallei. Bacillus pneumoniæ. Bacillus proteus. Bacillus of malignant œdema. Bacillus pyocyaneus. Bacillus of typhoid fever. Bacillus of fowl cholera. Bacillus of rabbit septicæmia. Bacillus of swine plague. Spirillum of Asiatic cholera. Spirochæte pallida. 3. BACTERIA STAINING BY THE TUBERCLE-BACILLUS METHOD. (ZIEHL-NEELSEN.) 1. Tubercle-bacillus. 2. Lepra-bacillus. 3. Smegma-bacillus. 4. Lustgarten’s bacillus. 1. Stain sections by floating thin paraffin sections directly on to warm carbol-fuchsin (fuchsin 1 grm., absolute alcohol 10 cc., cryst. carbolic acid, 5 grms., water 100 cc.) for 1-3 minutes. 2. Transfer on spatula to water, agitating so as to wash off excess of stain. 3. Transfer section to 30 per cent nitric acid and water alternately, until section has a pale lilac tint. 4. Wash in water. 5. Float on warm watery methylene-blue for 1 minute. 6. Wash in water. 7. Float section on slide; dry over flame or in oven; melt over flame, and put section at once into xylol to remove paraffin. 8. Balsam. Various staining-methods have been recommended for the staining of the most important pathogenic bacteria in tissues. The most useful of these methods are here given:— _a. Cocci._ 1. =Pyogenic Cocci.= Stain by Gram-Weigert’s, contrast with Bismarck brown or lithium-carmine. 2. =Pneumococcus.= Stains with ordinary water solutions, carbol-fuchsin and Gram-Weigert’s. The staining of the capsule in sections is not very satisfactory. 3. =Gonococcus.= Gram-negative. Stains in sections with Zieler’s method, Löffler’s methylene-blue, or dilute carbol-fuchsin with differentiation in alcohol. 4. =Micrococcus Catarrhalis.= Stains like the gonococcus. 5. =Diplococcus Intracellularis Meningitidis.= Smear preparations often Gram-positive, in sections usually Gram-negative. Use same stains as for gonococcus.