Bouillon, } Agar streak, } Blood serum, } Litmus milk. } and incubate at 37°C. Agar streak, } Gelatine stab, } Potato. } and incubate at 20°C. Compare the naked-eye appearances of the cultures from day to day. Note M. agilis refuses to grow at 37°C. 2. Make hanging-drop preparations from the bouillon and agar cultivations after twenty-four hours' incubation. Examine microscopically and compare. Note the locomotive activity of M. agilis and the Brownian movement of the remaining micrococci. 3. Prepare cover-slip films from the agar cultures, after twenty-four hours' incubation. Stain for flagella by the modified Pitfield's method. Note M. agilis is the only micrococcus showing flagella. 4. Make microscopical preparations of each from all the various media after twenty-four and forty-eight hours and three days' incubation. Stain carbolic methylene-blue, carbolic fuchsin, and Gram's method. Examine the films microscopically and compare. Note in the Gram preparation, the Gram negative character of certain individual cocci in each film prepared from the three days' growth--such cocci are dead. 5. Stain section of kidney tissue provided (showing abscess formation by Staphylococcus aureus) by Gram's method, and counterstain with cosin. 6. Stain film preparation of pus from an abscess (containing Staphylococcus pyogenes aureus) with carbolic methylene-blue and also by Gram's method, counterstained with cosin. 7. Inoculate[15] a white mouse subcutaneously with three loopfuls of a forty-eight-hour agar cultivation of the Staphylococcus aureus, emulsified with 0.2 c.c. sterile broth. Observe carefully during life, and when death occurs make a careful post-mortem examination. II. _Pyogenic cocci._ Micrococcus gonorrhoeæ. Micrococcus intracellularis meningitidis (meningococcus). Micrococcus catarrhalis. Micrococcus tetragenus. Micrococcus paratetragenus. III. _Pyogenic cocci._ Streptococcus pyogenes longus. Streptococcus of bovine mastitis. Streptococcus lanceolatus (Diplococcus pneumoniæ or pneumococcus). to contrast with Streptococcus brevis. Streptococcus lebensis. IV. _Pyogenic bacilli._ Bacillus pneumoniæ (Friedlaender). Bacillus rhinoscleromatis. Bacillus lactis aerogenes. V. _Pyogenic bacilli._ Bacillus pyocyaneus. to contrast with Bacillus fluorescens liquefaciens. Bacillus fluorescens non-liquefaciens. VI. _Pneumonia group._ Streptococcus lanceolatus (pneumococcus). Bacillus pneumoniæ (Friedlaender). Streptococcus pyogenes longus. VII. _Diphtheroid group._ Bacillus diphtheriæ (Klebs-Loeffler). Bacillus Hoffmanni. Bacillus xerosis. Bacillus septus. VIII. _Coli-typhoid group._ B. typhi abdominalis (B. typhosus). B. coli communis. B. enteritidis (Gaertner). to contrast with B. aquatilis sulcatus. IX. _Escherich group._