Part 5

It is ærobic (facultative anærobic), non-liquefying, and, in fluids, very actively motile, the movements lasting for months in preserved specimens (Smith). It grows luxuriantly in various culture media, and especially in alkaline ones, at the room temperature, and most actively at 85° to 100° F. It may grow as low as 60° to 70° F. and as high as 104°. (Swine plague bacillus grows at 55.4°).

On peptonized gelatine the surface colonies are usually round and flattened, those in its substance globular and smaller, and those at the bottom expanded next the glass and rising in the center into the gelatine like a knob. At 48 hours they appear as opaque whitish points and slowly increase to ½ to 2 mm. They may be brown by transmitted light, the depth of color increasing with age. On agar the colonies are grayish, shining and translucent and may reach the size of 4 to 6 mm. On potato (alkaline) a straw yellow film is formed, darkening with growth. In bouillon a turbidity appears in 24 hours, and in 1 or 2 weeks a precipitate and surface film.

The bacillus is usually larger in the gelatine and smaller in the bouillon than it is in the tissues. It seems to produce neither phenol nor indol.

Its behavior with sugars is significant. It ferments glucose producing acid and gas; does not ferment saccharose nor lactose, but turns the saccharose solution alkaline (no gas). In bouillon containing muscle glucose, it may without additional glucose form a little gas. The swine plague bacillus ferments saccharose producing acids but no gas: it ferments neither glucose nor lactose but turns the former acid.

Milk is neither coagulated nor soured by the hog cholera bacillus, but in 3 to 4 weeks it undergoes a change, becoming saponified.

Cultures have no special nor offensive odor. Some varieties in close tubes may cause a faint acid odor.

Oxygen is not essential to the success of a culture. The colonies form as promptly and as large in the depths of gelatine, or in a vacuum, as if in free air.

The following table will serve to show differences between the hog cholera bacilli, and related pathogenic microbes:

=Hog Cholera.= =McFadyean’s.= =Swine Plague.=

B. Choleræ Suis Swine Fever B. B. Pestis Suis

1.2 to 2μ × 5 to 0.8μ 2 to 2μ × 0.6μ 0.8 to 1.5μ × 0.6 to 0.8μ

Ends rounded Ends rounded Ends rounded

Involution forms Involution forms

Actively motile in Actively motile Nonmotile liquids

Flagella No Flagella

Stains throughout, Polar or uniform faint From fresh organs polar lighter in center stain stain, from old cultures uniform

Bleaches in Gram’s (I) Bleaches in Gram’s (I) Bleaches in Gram’s (I) Solu Solu Solu

Ærobic (Fac. Anærobic) Ærobic Ærobic, (Fac. Anærobic)

Vigorous growth in Slight growth in Weak growth in alkaline alkaline nutrient alkaline nutrient nutrient fluids fluids fluids

Active growth on potato No growth on potato On potato at 37° C. a yellowish, becoming slight, thin gray, darker waxy layer

On gelatine, small, On gelatine light On gelatine feeble round brownish bluish colonies growth or none colonies shading off insensibly at edges

Nonliquefying Nonliquefying Nonliquefying

On agar conical On agar slight, On agar, grayish colonies, grayish, transparent, almost translucent, or white, semi- invisible growth brown, knobbed, translucent shining waving edges

In milk grows freely, Grows in milk, no clot Grows in milk, no acid, no acid, no clot: no clot Saponifies in 3 or 4 weeks

Forms no indol in Forms no indol in pancreatic bouillon pancreatic bouillon

Ferments glucose, Does not ferment forming acid and gas glucose, forms acid, no gas

Lactose not fermented Lactose not fermented

Saccharose not Saccharose fermented, fermented; forms acid, no gas alkalinity; no gas