32 MEMOIRS OF TEE NATIONAL ACADEMY OF SCIENCES. 



Liquefaction takes place in saucer shape; not extensive. The colonies become more dense, and 

 after five days a finely patterned edge with leafy outlines is seen around them. The mottled or 

 marbled appearance is lost, and dark wavy lines running a long distance are seen. After this 

 time the liquefaction is too extensive to make further observation. 



Agar slant. — A thin translucent layer, almost without color, with irregular margins, is 

 formed, and reaches the tube wall near the bottom after several days. It is smooth and shining, 

 ;i faint greenish tint by transmitted light. The smooth surface is lost after some time by the 

 growth of small rounded elevations, like colonies. The agar acquires a faint greenish tint. 



Gelatin stab. — Good growth deep down, with a button on the surface. By the third day a 

 small saucer of liquefaction has formed, which soon reaches the tube wall. At the end of a week 

 the liquefaction is 1 cm. deep and the floor almost level, and covered with a whitish 

 flocculeut precipitate, the liquefied gelatin being clear. A mycoilerma floats on the 



3 surface. The gelatin below the floor acquires a hazy look and liquefaction pro- 



4 gresses slowly, being complete in about six weeks. 

 s Potato. — Growth is seen on the second day along the line of inoculation. It 



soon becomes a slimy-looking, dirty light-brown layer, which covers most of the 

 plug at the end of a week, passing around behind it. It is thick and moist and 

 has a smooth surface. The color changes to yellowish brown as it grows older. 



Bouillon. — Diffuse cloudiness by the second day. A thin pellicle which sinks 

 easily is formed on the surface after ten days. The growth settles to the bottom, 

 leaving the liquid quite clear. 

 Bosolic acid. — Becomes a cherry red in twelve to fourteen days, and a pellicle forms on the 

 surface. 



Litmus mill;. — Becomes more blue after five or six days, then becomes watery and translucent. 

 The color is almost all gone in twelve days, while a blue zone forms at the surface on the tube 

 wall. The. casein becomes dissolved without previous coagulation. Reaction alkaline. 



Sugar gelatin, deep stab. — Grows only near surface. Same appearance as in plain gelatin. 

 Tndol. — Good reaction with both sulphuric acid and sodium nitrite 

 Relation to temperature. — More rapid and abundant at 35° to 36° C. 



Bacillus Pinnatus. 



(Figs. 28 and 20, PI. III.) 



Found at the depth of C feet in made soil, which had been paved for several years. 



Character. — Grows well in an atmosphere of hydrogen. 



Morphology. — Slender, short, straight rods with rounded ends, three to five times as long as 

 I in kkI. Occurs singly or in chains of two and three elements. In old cultures the rods are so 

 short as to be oval. 



Spores have not been observed. 



Motility. — The movements are slow and mostly rotatory, but now and then a rod will move 

 some distance across the field. 



Flagella not demonstrated. 



Colonies on gelatin plates. — Colonies become visible in thirty to thirty-six hours as bluish 

 dots, which appear as finely granular disks with smooth edges under a low power. At the end of 

 sixty hours the surface colonies are one-half of a millimeter in diameter, and stand up from the 

 surface like minute drops of milk. The deep colonies are punctiform. x 80. Deep are finely 

 granular, yellowish, and have smooth edges. The surface colonies are made up of a central 

 portion of yellowish-brown color, finely granular, and growing uniformly lighter from center 

 to edge. Outside of this is a zone of pale gray in which no structure can be made out. The 

 division between the two is sharply defined by a line of light. The edges are clear-cut and 

 even. Some colonies are oval, but most of them are circular, and all have the same general 

 structure. The colonies grow more dense as they get older, the center becomes brownish, and 

 the line of demarkation between the zones less distinct. The colonies never grow larger than 

 1 mm. in diameter, and no liquefaction is caused. 



