MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



11 



Tndol. — Reaction negative. 



Relation to temperature. — Grows well at both room temperature and at 35° to 36° C. 



Xote. — This may be identical with the Sarcinaflava (De Barry). The published descriptions 

 are so meager that positive identification has not been possible. The chief difference noted has 

 been in the growth on potato. I have not been able to obtain any growth, while the growth of 

 the Sarcinaflava is scanty and limited to the line of inoculation. 



Bacillus Megatherium. 



(Figs. 1, 2, H. 4, and 5, PI. I.) 



Very common in soil, both made and virgin, at all depths where bacteria are found at all. In 

 the course of this work it was found as low as 7 feet in made soil which had been paved for a 

 number of years. 



Character. — It is a strict aerobe, no development occurring in an atmosphere of hydrogen. 



Morphology. — Thick straight rods, with rounded ends, from three to five times as long as 

 broad. It forms quite long chains, in which the rods are often bent on each other and are of 

 unequal lengths. The rods show a peculiar granulation of their contents, said to be peculiar to 

 this organism. 



Spore formation is usually well advanced at the end of sixteen hours in a warm room. The 

 rods appear to grow shorter and oval, while the center is occupied by a long oval spore almost as 

 long as the rod itself. In cultures thirty six hours old chains of spores are seen, which are often 

 pushed together, the ends overlapping each other. 



Motility. — Slight movements are seen, which have been described as "amoeboid." 



Flagella not demonstrated. 



Colonies o» gelatin jrfates. — Colonies are seen at the end of twelve to sixteen hours as whitish 

 dots. xSO. The deep appear brown and have regular margins. No structure can be made out. 

 Those on the surface are lighter in color and have very irregular margins. The center is too dense 

 to show much structure, but where any can be made out consists of a cloudy mass of interwoven 

 and tangled filaments. By the third day the surface colonies are each in a saucer of liquefaction, 

 4 mm. in diameter, in which floats a whitish island with irregular margins, surrounded by a 

 zone of opaque grayish liquefied gelatin. xSO. Deep are unchanged. The surface show the 

 dense cloudy masses in the center, merging into the lighter masses made up of broken and 

 tangled filaments floating in the liquefied gelatiu. The margins of the saucer of liquefaction are 

 even. When a colony has begun beneath the surface and broken through there is a well-defined 

 darker center, surrounded by a ragged fringe of coarse filaments. In some colonies this fringe is 

 much more regular, and assumes a festoon-like arrangement, going out in bundles at tolerably 

 regular intervals, which divide to the right and left, joining those next them, thus forming a 

 series of loops or festoons around the colony. This arrangement is lost in twenty-four hours by 

 the liquefaction of the gelatin, and only broken filaments can be seen around the colony. 



Agar slant. — The growth is at first a creamy white color, and forms abundantly, sometimes 

 being piled up 1 mm. in height. The surface is moist, smooth, and 

 glistening. It often becomes yellowish in color, and forms a thick pasty 

 mass, with a strong smell of stale milk. After several generations on 

 agar it changes its character, apparently, and forms a thin dirty gray 

 layer, the agar becoming brownish after a time. 



Gelatin stab. — Liquefaction occurs in two different ways, according 

 to the vigor of the growth apparently. In rhe first a saucer of liquefac- 

 tion is formed, which increases, reaching the tube wall and becoming 

 deeper. Whitish flocculi float in the liquid and gradually settle to the 

 floor, which becomes level. In other cultures growth takes place deep 

 down the stab, and liquefaction occurs in funnel form by the second day. 

 The floor becomes level after ten to twelve days. 



Potato. — A thick band, whitish and looking like melted candy, is formed by the second day. 

 It is smooth and glistening. It increases rapidly, and is thrown into large folds and wrinkles by 



A. B. 



Gelatin stab. 



