394 THE BACILLUS LACTIMORBI OF TREMBLES 



organs the bacilli are longer and more slender than the colon bacillus; 

 they stain occasionally unevenly with methylene blue. In preparations 

 made from cultures grown on agar at 37 C., the organism is found 

 to be a rod, a little smaller than the anthrax bacillus, occurring singly 

 and in pairs and in occasional filaments. As a rule, the rods, at the 

 end of twenty-four hours' incubation, do not stain deeply with 

 methylene blue, even if the solution be slightly heated, but at one or 

 both poles and at the centre of each rod metachromatic granules are 

 found which take on a reddish or purple tint. In young cultures the 

 bacilli are Gram positive. Spore formation occurs after twenty-four 

 hours' incubation, the spores may be first oval, but when completely 

 mature they are round. They lie near one end of the rod. The 

 organism is motile and possesses ten to fifteen peritrichous flagella, 

 which can be demonstrated by van Ermengem's method. 



Cultural Properties. The cultural characteristics of the organism 

 are as follows: On agar slants incubated at 37 C., at the end of 

 twenty-four hours, the surface is more or less irregularly covered 

 by a delicate veil-like growth, which is more profuse at the end of 

 from forty-eight to seventy-two hours; on some cultures it may 

 eventually take on a semiviscid character. The color is grayish, 

 moist, smooth, and glossy; there is no pigmentation of the growth 

 itself or of the medium. There is no gas, the condensation water- 

 growth is heavy, gray white in color; no odor being present. No 

 gas is formed in glucose agar cultures. In bouillon, at the end of 

 twenty-four hours, no growth except sometimes a slight clouding at 

 the surface, may be noticeable. At the end of twenty-four hours a 

 well-formed pellicle, which will sink if the tube is agitated, appears on 

 the surface. The remainder of the medium is feebly clouded, and 

 there may be a fine semiflocculent sedimented growth at the bottom 

 of the tube. Milk becomes alkaline after a number of days, but 

 coagulation does not occur; there is no growth on potatoes. In gelatin 

 stab cultures, kept at 20 C., the growth begins to appear at the end 

 of forty-eight hours, but is not well developed until at the end of 

 seventy-two hours. There is little or no surface growth, but down 

 the stab to the extent of about 2 centimeters, a delicate, smooth, 

 gray growth appears. At the end of a week the surface growth has 

 extended as a fairly well-developed film of a whitish color, smooth, 

 moist, and glossy; at times the first evidence of liquefaction may now 

 be detected, but this is not well established until the tenth day, when 

 the medium is slightly fluid just beneath the surface growth. As time 

 passes liquefaction slowly progresses. The growth in gelatin leads to 

 a more or less well-defined putrescent odor. Agar plate colonies at the 

 end of twenty-four hours' incubation at 30 to 37 C. resemble those 

 of the Streptococcus pyogenes, but with this difference, that they show 

 a tendency to spread out in a film, particularly if the agar is freshly 

 made; in the latter case the whole surface of the plate may be covered. 

 In gelatin plates grown at 20 C. the colonies make their appearance 

 at the end of from forty-three to seventy-two hours, and resemble at 



