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 gonorrhoeae.

Micrococcus intracellularis meningitidis (meningococcus).

Micrococcus catarrhalis.

Micrococcus tetragenus.

Micrococcus paratetragenus.

III. _Pyogenic cocci._

Streptococcus pyogenes longus.

Streptococcus of bovine mast.i.tis.

Streptococcus lanceolatus (Diplococcus pneumoniae or pneumococcus).

to contrast with Streptococcus brevis.

Streptococcus lebensis.

IV. _Pyogenic bacilli._

Bacillus pneumoniae (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 pneumoniae (Friedlaender).

Streptococcus pyogenes longus.

VII. _Diphtheroid group._

Bacillus diphtheriae (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._

B. coli communis (Escherich).

B. coli communior.

B. lactis aerogenes.

B. cloacae.

X. _Gaertner group._

Bacillus enteritidis (Gaertner).

B. paratyphosus A.

B. paratyphosus B.

Bacillus cholerae suum (Hog Cholera).

B. psittacosis.

XI. _Eberth group._

B. typhosus (Eberth).

B. dysenteriae (Shiga).

B. dysenteriae (Flexner).

B. faecalis alcaligines.

XII. _Spirillum group._

Vibrio cholerae.

Vibrio metschnikovi.

to contrast with Vibrio proteus (Finkler and Prior).

Spirillum rubrum.

Spirillum rugula.

XIII. _Anthrax group._

Bacillus anthracis.

to contrast with Bacillus subtilis.

Bacillus mycoides.

Bacillus mesentericus fuscus.

XIV. _Acid fast group._

Bacillus tuberculosis (human).

" " (bovine).