5. Test the peptone water itself for the presence of indol and nitrite by the addition of pure concentrated H_{2}SO_{4}. 5. Prepare gelatine and agar plates in the usual way from such of these tubes as show pellicle formation. 6. Pick off from the plates any colonies resembling those of the Vibrio choleræ and subcultivate upon all the ordinary laboratory media. 7. Test the vibrio isolated against the serum of an animal immunised to the Vibrio choleræ for agglutination. ~B. Anthracis.~-- 1. Transfer 5 c.c. of the emulsion from the filter candle to a sterile test-tube and plug carefully. 2. Place the test-tube in the interior of the benzole bath employed in separating out spore-bearing organisms (_vide_ page 257), and expose to a temperature of 80° C. for twenty minutes. 3. Inoculate a _young_ white rat subcutaneously (on the inner aspect of one of the hind legs) with 1 c.c. of the emulsion. Observe during life, and, if the animal succumbs, make a complete post-mortem examination. 4. Melt three tubes of nutrient agar in boiling water and cool to 42° C. 5. Number the tubes 1, 2, and 3. To No. 1 add 0.2 c.c., to No. 2 add 0.3 c.c., and to No. 3 add 0.5 c.c. of the suspension, and pour plates therefrom. 6. Incubate at 37° C. for twenty-four or forty-eight hours. 7. Pick off any colonies resembling those of anthrax and subcultivate on all the ordinary laboratory media. 8. Inoculate another young white rat as in 3, using two loopfuls of the agar subcultivation emulsified with 1 c.c. sterile bouillon. Observe during life, and if the animal succumbs, make a complete post-mortem examination. ~B. Tetani.~-- 1. Proceed as detailed above in steps 1 and 2 for the isolation of the B. anthracis. 2. Add 1 c.c. of the suspension to each of three tubes of glucose formate broth, and incubate anaerobically in Buchner's tubes at 37° C. 3. From such of the tubes as show visible growth (with or without the production of gas) after twenty-four hours' incubation inoculate guinea-pigs, subcutaneously (under the skin of the abdomen), using 0.1 c.c. of the bouillon cultivation as a dose. Observe carefully during life, and, if death occurs, make a complete post-mortem examination. 4. From the same tubes pour agar plates and incubate anaerobically in Bulloch's apparatus, at 37° C. 5. Subcultivate suspicious colonies on the various media, incubate anaerobically, making control cultivations on glucose formate agar, stab and streak, to incubate aerobically and carry out further inoculation experiments with the resulting growths. EXAMINATION OF MILK.