Bacilli Resembling the Typhoid Bacillus 667 



They are rarely larger than 0.5 mm. in diameter and are homogeneous through- 

 out. The superficial colonies have little tendency to spread upon the gelatin. 

 They rarely reach a greater diameter than 2 mm. The gelatin is not liquefied. 



Upon agar-agar they attain a diameter of 4 mm. and have a gray, translucent 

 appearance with polished surface. They are round and slightly arched. Upon 

 Conradi-Drigalski agar-agar plates the colonies are blue. On Loffler's nialachite- 

 green plates, transparent colonies appear surrounded by a yellowish change in the 

 agar. 



Gelatin. — In gelatin punctures the growth takes the form of a nail with a flat 

 head. There is nothing characteristic about it. The medium is not liquefied. 



Agar-agar. — Linear cultures upon agar-agar present a translucent, circum- 

 scribed, grayish, smeary layer without characteristic appearances. 



Potato. — Upon potato a yellowish coating is formed, especially when the cul- 

 ture is kept in the thermostat. No growth occurs upon acid potato. 



Bouillon. — Bouillon made with or without peptone is clouded in twenty-four 

 hours. When the culture is allowed to stand for a couple of weeks without being 

 disturbed, a thin surface growth can be observed. 



Milk is an excellent culture-medium; after a slight initial acidity it becomes and 

 remains alkaline in reaction. 



Vital Resistance. — Smith found the bacillus vital after being dry for four 

 months. It ordinarily dies sooner, however, and difficulty may be experienced in 

 keeping it in the laboratory for any length of time unless frequently transplanted . 

 The thermal death-point is s8°C., maintained for ten minutes. 



Metabolic Products. — Gas Production. — The hog-cholera bacillus is capable of 

 breaking up dextrose, arabinose, xylose, fructose, galactose, mannose, maltose, 

 dulcite, mannite and sorbite into CO2, H, and an acid, which, formed late, even- 

 tually checks its further development. It does not ferment saccharose or lactose, 

 nor does it decompose glycogen, inulin, adonite, starch, erythrite or raffinose. 



Indol. — No indol and no phenol are formed in the culture-media, but H2S is 

 formed from peptone. 



Toxin. — In pure cultures of the hoe-cholera bacillus Novy* found a poisonous 

 base with the probable composition CieHssNz, which he gave the provisional 

 name "susotoxin." In doses of 100 mg. the hydrochlorid of this base causes con- 

 vulsive tremors and death within one and one-half hours in white rats. He has 

 also obtained a poisonous protein of which 50 mg. were fatal for white rats, and 

 which immunized them against highly virulent hog-cholera organisms, when 

 administered by repeated subcutaneous injection. 



DeSchweinitzf has also separated a slightly poisonous base which he calls 

 "sucholotoxin," and a poisonous protein that crystallizes in white, translucent 

 plates when dried over sulphuric acid in vacuo, forms needle-like crystals with 

 platinic chlorid, and was classed among the albumoses. 



Pathogenesis. — The bacillus is disappointing in its effects uponhogs. When 

 it is subcutaneously or intravenously introduced into such animals or fed to them, 

 they sometimes show no signs of disease; sometimes show fever and depression, 

 but rarely sicken enough to die. Animals thus made ill do not communicate 

 hog cholera to others. 



Smith found that 0.75 cc. of a bouillon culture injected into the breast muscles 

 of pigeons would kill them. 



In Smith's experiments one four-miUionth of a cubic centimeter of a bouillon 

 culture injected subcutaneously into a rabbit was sufficient to cause its death. 

 The temperature abruptly rises 2° to 3°C., and remains high until death. Sub- 

 cutaneous injection of larger quantities may kill in five days. Injected intra- 

 venously in small doses the bacillus may kill rabbits in forty-eight hours. 



Agglutination. — Pitfieldt found that after a single injection of a killed bouillon 

 culture of the bacillus into a horse, the serum, which originally had very slight 

 agglutinative power, showed a decided increase. If the horse be immunized to 

 large doses of such sterile cultures, the serum becomes so active that with a dilu- 

 tion of 1 : 10,000 a typical agglutination occurs in sixty minutes. 



McClintock, Boxmeyer and Siffer§ found that the serUm of normal hogs 

 agglutinates strains of ordinary hog-cholera bacilli in dilutions occasionally as 



* "Medical News," 1900, p. 231. 



t "Medical News," igoo, p. 237. 



t "Microscopical Bulletin," 1897, p. 35. 



§ "Jour, of Infectious Diseases," March i, 1905, vol. 11, No. 2, p. 351. 



