Bacillus Subtilis, Ehrenberg. 



HAY BACILLUS. 



ORIGIN. In air, water, soil, feces, putrid fluids, and in 

 infusions of hay. 



FORM. Large, rather thick rods, 3-4 times as long- 

 as wide, with rounded ends. Usually in pairs, often in threads. 



MOTILITY. -Active snake-like motion. 8-12 lateral flagella. 



SPORULATION. It forms large, oval spores at or near 

 the middle, without enlargement. They are highly resist- 

 ant and can be readily double stained. Germination, p. 54. 



ANILIN DYES. Stain readily; so does Gram's method. 



GROWTH. Very rapid. At 21 cell division has been 

 observed to take place in 75 min. ; and at 35 in 20 min. 



GelaMn plates. The surface colonies liquefy gelatin rapidly and 

 extensively, and present a striking- appearance. The central portion 

 appears as a grayish yellow, irregular mass, which on close examina- 

 tion can be seen to be made up of moving cells. This central portion 

 is surrounded by a lighter, granular zone. The border of the colony is 

 quite characteristic. It consists of a dense zone of bacilli and 

 threads, radially arranged, so that the ends project outward, thus 

 presenting a peculiar appearance the so-called "ray crown." 



Stab culture. Very rapid, funnel-shaped liquefaction takes place 

 along the entire line of inoculation. White flocculent masses ac- 

 cumulate at the bottom while the liquid above, at first turbid, becomes 

 clear. On the surface a dense white scum or zooglea usually forms. 



Streak culture. On agar, it forms a dull grayish white, thick, 

 folded scum. On potato, it develops excellently, and forms a moist, 

 thick, yellowish-white covering, which at first is velvety in appear- 

 ance but later becomes dry and granular, and contains spores as well 

 as involution forms. On blood-serum, it also forms a folded scum and 

 liquefies. 



OXYGEN REQUIREMENTS. It is aerobic. 



TEMPERATURE. Grows from 10 to 45. Optimum about 30. 



BEHAVIOR TO GELATIN. -It liquefies rapidly and extensively. 



PATHOGENESIS. It has no pathogenic power. When 

 a large number of spores, are injected into the blood they 

 ,soon disappear and are taken up by the liver and spleen. 

 They may be stored up in these organs for 60 to 70 days 

 and yet preserve their vitality (Wyssokowitsch). 



A large number of bacilli resemble the above B. subtilis 

 to a marked extent. It is customary, therefore, to speak 

 of the group of hay bacilli. 



212 



