5. Pipette off the supernatant fluid, fill up with sterile distilled water, cork the tube and shake to distribute the deposit throughout the water. Again centrifugalise. 6. Repeat steps 4 and 5 twice more. 7. Employ one portion of the final deposit to inoculate guinea pigs. 8. Plant the remainder of the deposit freely on Dorset's Egg medium; cap and incubate at 37°C. NOTE.--If only microscopical films are needed, fill up the centrifuge tube with Ligroin (a petroleum ether) in place of sterile distilled water in step 5 and prepare the films from the _surface_ of the fluid, to stain by the Ziehl-Neelsen process. INDEX Abbé's condenser, 7 Abbott's stain for spores, 107 Aberration, chromatic, 56 spherical, 55 Absolute alcohol as a fixative, 82 as an antiseptic, 27 Absorbent paper for drying cover-slips, 69 A. C. E. mixture, 345 Acetic acid for clearing films, 82 Achromatic condenser, 54 Acid hæmatin, 96 production, analysis table, 283 by bacteria, 145 investigation of, 280 qualitative examination, 283, 284 quantitative examination, 280 Acid-fast bacilli in tissues, to stain, 124 Action of various gases on bacteria, 295 Active immunisation, illustrative example, 322 Adjustable water bath, 299 Aerobic cultures, 221 Aerogenic bacteria, 131 Aesculin agar, 204 Agar gelatine (guarniari), 194 methods of preparation, 167 surface plates, 232 Agar-agar, preparation of, 167 Agglutination reaction, macroscopical, 386 microscopical, 385 Agglutinin, 381 Air, analysis of, 468 filter, 40 pump, Geryk, 43 Albumin solution, Mayer's, 120 Alcohol production, test for, 285 Alkaline pyro, 239 Alum carmine, 96 Ammonia production test for, 285 Amphitrichous bacteria, 136 Anaerobic cultures, 236 Botkin's method, 243 Buchner's method, 238 Bulloch's method, 245 Hesse's method, 237 McLeod's method, 240 media, 180 Novy's method, 244 Anaerobic cultures, Roux's biological method, 237 physical method, 237 vacuum method, 238 Wright's method, 239 Anæsthetics, 345