6. =Micrococcus Tetragenus.= Stain with Gram’s or watery solutions of basic aniline dyes. _b. Bacilli._ 1. =Anthrax-bacillus.= Stain with Gram-Weigert’s and contrast with Bismarck brown or lithium-carmine. Stains also with strong watery gentian-violet solution, with differentiation in strong alcohol. 2. =Bacillus of Malignant Oedema.= Gram-negative. Stain with watery solution or gentian-violet. 3. =Bacillus of Tetanus.= Gram-positive. Stains with watery solutions of basic aniline dyes. 4. =Bacillus Aërogenes Capsulatus.= Gram-positive. Stains with other aniline stains. 5. =Bacillus Pyocyaneus.= Stains with Gram’s and other aniline dyes. 6. =Bacillus of Influenza.= Gram-negative. Fix tissue in alcohol. Stain with dilute carbol-fuchsin and differentiate in dilute acetic acid. 7. =Koch-Week’s Bacillus.= Gram-negative. 8. =Bacillus of Bubonic Plague.= Gram-negative. Stain by _Gaffky’s method_ (Fix in alcohol or a mixture of glacial acetic acid 10.0, chloroform 30.0, and 96 per cent alcohol 60.0, imbed in paraffin, stain 2-3 hours in weak watery methylene-blue, dehydrate quickly in absolute alcohol, xylol, balsam). It may also be stained by 24 hours in concentrated solution of fuchsin in glycerin, rapid differentiation in weak acetic; alcohol; xylol; balsam. Alcohol or mercuric chloride fixation should be used, as formol fixation does not give good staining. 9. =Typhoid Bacillus.= Löffler’s methylene-blue or carbol-fuchsin, staining 24 hours, decolorizing in dilute acetic and washing rapidly in alcohol. Zieler’s method may also be used. It is Gram-negative. 10. =Paratyphoid Bacillus.= Stains like the typhoid bacillus. 11. =Colon Bacillus.= Gram-negative. May be stained with Löffler’s methylene-blue or carbol-fuchsin. 12. =Diphtheria Bacillus.= May be stained in sections of diphtheritic membranes with Löffler’s methylene-blue, watery aniline stains, or with Gram’s if the decolorization is not carried too far. 13. =Bacillus of Chancroid.= Gram-negative. Stain according to _Unna’s method_:— 1. Fix in alcohol. 2. Stain 5-10 minutes in a mixture of a solution of methylene-blue 1 grm., potassium carbonate 1 grm., alcohol 20 cc., water 100 cc., and a solution of methylene-blue 1 grm., borax 1 grm., water 100 cc. 3. Place sections on slide; blot. 4. Decolorize in Unna’s glycerin-ether mixture. 5. Dry; dehydrate in alcohol. 6. Xylol; balsam. 14. =Bacillus of Glanders.= Gram-negative. Stain with Zieler’s method or with Löffler’s methylene-blue, differentiating in weak acetic. _Noniewicz’s Method._ 1. Stain with Löffler’s methylene-blue 2-5 minutes. 2. Wash in water. 3. Differentiate for about 5 seconds in a mixture of ½ per cent acetic acid 75 cc., ½ per cent watery solution tropaeolin 25 cc. 4. Wash in water; dry by blotting; xylol; balsam.