NON-PATHOGENIC BACILLI. 079 



380. BACILLUS SUBTILIS siMiLis (Sternberg). 



Obtained in cultures from the liver of a yellow-fever cadaver in Ha- 

 vana, 1889. 



Morphology. Bacilli with slightly rounded ends, from 2 to 4 ^ long 

 and about 1 M thick ; grow out into jointed filaments. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 

 ing, motile bacillus. Forms long-oval spores, which are centrally located 

 and nearly as long as the cells in which they are developed. The motion is 

 like that of Bacillus subtilis, viz. : a slow, to-and-fro, progressive movement. 

 Upon gelatin plates the deep colonies, at the end of thirty-six hours at the 

 room temperature, are spherical, finely granular, and pearl-like by reflected 

 light; the superficial colonies have commenced to liquefy the gelatin at this 

 time, and have a granular, white mass at the centre surrounded by a saucer- 

 shaped cavity containing liquefied gelatin. In gelatin stick cultures lique- 

 faction does not occur as rapidly as with Bacillus subtilis ; at the end of ten 

 days at the room temperature the upper half of the gelatin is liquefied and 

 small, pearl-like colonies are scattered along the line of puncture below; on 

 the floor of the liquefied gelatin is a flocculent, white deposit and a thin my- 

 coderma is seen upon the surface. On potato a dry, yellowish- white layer 

 the size of a dime is formed at the end of forty -eight hours at 30 (J., and 

 the bacilli, which grow out into long, jointed filaments, contain spores. 

 Upon the surface of agar a thick, cream-white layer is formed in four or 

 five days at the room temperature. In agar stick cultures there is a branch- 

 ing growth along the upper portion of the line of puncture; in old agar cul- 

 tures variously contorted involution forms are seen in the surface growth 

 and but few spores are present. 



381. BACILLUS LEPTOSPORUS (L. Klein). 



Obtained as an accidental contamination of a pure culture from the air ? 



Morphology. Resembles Bacillus subtilis; when cultivated at 35 C. 

 forms short chains ; at 18 to 20 C. grows out into long, twisted and inter- 

 laced filaments. Forms spores which are 0.6 u thick and 1.5/tlong; in 

 vegetating, these first increase in thickness to 1 to 1.2 # the thickness of the 

 vegetative cells; the spores have a membranous envelope consisting of two 

 layers, and are Fsurrounded by a jelly-like substance having a dull silvery 

 lustre ; vegetation occurs at the same time fi'om both poles, and the mem- 

 branous envelope is not ruptured and left intact after the emergence of the 

 vegetative cell, as is the case with Bacillus subtilis, but is gradually dis- 

 solved, or serves as the cell wall of the newly formed bacillus (?). 



Biological Characters. Characters of growth in solid culture media not 

 given. The motions are said to be peculiar, especially in filaments made up 

 of four, eight, or sixteen elements ; one end of the chain is jerked hither 

 and thither with a whip-like, convulsive motion, by which the elements are 

 thrown into various and constantly changing angular figures. 



382. BACILLUS SESSILIS (L. Klein). 



Found in the blood of a cow supposed to have died of anthrax. 



Morphology. Resembles Bacillus subtilis, but is distinguished from this 

 species by the germination of the spores. 



Biological Characters. An aerobic, non-motile bacillus. In alkaline 

 bouillon at 28 C. a diffuse cloudiness is seen on the second day, and on the 

 fourth day a mycoderma is developed upon the surface, which contains spore- 

 bearing bacilli. The spores resemble those of Bacillus subtilis, but the ger- 

 mination of these reproductive elements is quite different and resembles 

 more that of Bacillus butyricus. The vegetative cell emerges from a rup- 

 ture at one of the poles of the exosporium, and a second rod appears to fol- 



