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