Agar plates,

Agar streak or smear,

Agar stab,

Inspissated blood-serum, at 20° C. and 37° C.

Bouillon,

Litmus milk,

Potato,

Special media for the purpose of demonstrating characteristic reactions.

2. Morphology.-(Vide Microscopical Examination of

Cultivations, page 218.)

Vegetative forms:

Shape.

Size.

Motility.

Flagella (if present).

Capsule (if present).

Involution forms.

Pleomorphism (if observed).

Sporing forms (if observed). Of which class?

Staining reactions.

3. Biology.-(Vide Physical Examination of Cultures,

4. Chemical Products of Growth.-(Vide Chemical Ex

amination of Cultivations, page 221.)

Chromogenesis.

Photogenesis.

Enzyme formation.

Fermentation of carbohydrates:

In glucose gelatine shake cultivation.
In saccharose gelatine or bouillon.
In lactose gelatine or bouillon.
In maltose gelatine or bouillon.
In glycerine bouillon or bouillon.

Acid formation.

Alkali formation (if present).

Indol formation.

Phenol formation.

Reducing and oxidising agents.

Gas formation.

5. Pathogenicity:

Susceptible animals.

Immune animals.

Experimental inoculation, symptoms of disease.

Post-mortem appearances.

Virulence:

Length of time maintained.

Upon what medium?

Minimal lethal dose.

Is virulence readily exalted and attenuated? Toxin formation.

MACROSCOPICAL EXAMINATION OF CULTIVATIONS.

In describing the naked-eye and low-power appearances of the bacterial growth the descriptive terms introduced by Chester (and included in the following scheme) should be employed.

Solid Media.

Plate Cultures.

Gelatine. Note the presence or absence of liquefaction of the surrounding medium. If liquefaction is present, note shape and character (vide page 215, "stab" cultures).

Agar. No liquefaction takes place in this medium. The liquid found on the surface of the agar (or at the bottom of the tube in agar tube cultures) is merely water which has been expressed during solidification and has subsequently condensed.

Gelatine and Agar.-Examine the colonies at various intervals

(a) With the naked eye.

(b) Under a low power (1 inch) of the microscope, or by means of a small dissecting microscope.

Distinguish superficial from deep colonies and note the characters of the individual colonies.

Fig. 114.-Types of colonies: a, Cochleate; b, amoeboid; c, mycelioid.

(A) Size.-The diameter in millimetres, at the various ages.

(B) Shape.

Punctiform: Dimensions too slight for defining form by naked eye; minute, raised, hemispherical.

Round: Of a more or less circular outline.
Elliptical: Of a more or less oval outline.
Irregular.

Fusiform: Spindle-shaped, tapering at each end. Cochleate: Spiral or twisted like a snail shell (Fig. 114, a).

Amoeboid: Very irregular, streaming (Fig. 114, b). Mycelioid: A filamentous colony, with the radiate character of a mould (Fig. 114, c).

Filamentous: An irregular mass of loosely woven filaments (Fig. 115, a).

Floccose: Of a dense woolly structure.

Rhizoid: Of an irregular, branched, root-like character (Fig. 115, b).

Conglomerate: An aggregate of colonies of similar size and form (Fig. 115, c).

Toruloid: An aggregate of colonies, like the budding

of the yeast plant (Fig. 115, d).

Rosulate: Shaped like a rosette. (C) Surface Elevation.

1. General Character of Surface as a Whole: Flat: Thin, leafy, spreading over the surface (Fig. 116, a).

Effused: Spread over the surface as a thin, veily layer, more delicate than the preceding.

Raised: Growth thick, with abrupt terraced edges (Fig. 116, b).

Convex: Surface the segment of a circle, but very flatly convex (Fig. 116, c).

Pulvinate: Surface the segment of a circle, but decidedly convex (Fig. 116, d).

Fig. 116.-Surface elevation of colonies: a, Flat; b, raised; c, convex; d, pulvinate; e, capitate; f, umbilicate; g, umbonate.

Capitate: Surface hemispherical (Fig. 116, e).

Umbilicate: Having a central pit or depression (Fig. 116, f).

Umbonate:

Having a central

convex nipple-like elevation (Fig. 116, 9).

2. Detailed Characters of Surface: Smooth: Surface even, without any of the following distinctive char

acters.

Alveolate: Marked by depressions separated by thin walls so as to resemble a honeycomb (Fig. 117).

Punctate: Dotted with punctures like pin-pricks.

Bullate: Like a blistered surface, rising in convex prominences, rather

coarse.

Vesicular: More or less covered with minute vesicles due to gas formation; more minute than bullate.

Verrucose: Wart-like, bearing wart-like prominences. Squamose: Scaly, covered

Corrugated: In long folds, due to shrinkage.