MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 37 



that in a few hours, if the weather be warm, the colony will attain a diameter of about 1 cm. 

 Each colony is saucer shaped, the liquefied gelatin almost perfectly clear, being a faint grayish 

 hue, and the edges smooth and regular, forming a perfect circle, x 80. Fine threads in tangled 

 masses are seen in the liquefied gelatin resembling, especially near the center, " a ballot string," 

 as Frankel so aptly describes it. The edge of the colony is made up of a corona of fine spear 

 points boring vertically into the gelatin, but somewhat wavy. These are much longer in a colony 

 which has just reached the surface. 



Agar slant. — An indistinct line along the inoculation soon appears, thin and spreading 

 irregularly at the margins. By the third day the growth has covered almost the entire surface of 

 agar, and the water at the bottom, and climbed up the tube ± mm. from the surface of the water. 

 It soon becomes thrown into tine wrinkles, becomes gray and then brownish, and looks as if fine 

 powder had been sprinkled over it. 



Gelatin stab. — Growth is mostly in upper part of stab, with a funnel of liquefaction at top. 

 The liquefaction reaches the tube wall in thirty-six to forty hours, but is not very deep. At the 

 end of ten days the floor has become level, about 1.5 cm. below the surface. It is covered with 

 whitish flocculi, while the liquefied gelatin is almost clear. A thin skin may form on the surface, 

 which becomes wrinkled. 



Potato. — Growth occurs first along needle stroke, and looks much as if the potato had been 

 scraped up from side to side. The surface of the plug is nearly covered on the third day, and the 

 growth has passed entirely around it where moist. It is thrown into large folds, aud looks as if 

 dusted with fine powder. It soon becomes dry looking, and dark gray, and is piled up 2 mm. high. 

 When touched with the needle it will draw out into quite long strings, being glutinous. 



Bouillon. — Diffuse cloudiness on second day. A thin pellicle soon forms on surface. The 

 growth settles to the bottom, leaving the liquid tolerably clear. 



Rosalie acid. — No change observed. 



Litmus milk. — Reddish tinge seen on third day, but no coagulation. The milk soon becomes 

 watery and translucent from digestion of the casein, and the color is entirely discharged by the 

 sixth day. A whitish mass floats on the surface, and in the bottom of the tube is a dense, 

 viscous mass. The reaction is alkaline. 



Sugar gelatin, deep stab. — Growth quite deep, with rapid liquefaction. No gas production. 



Indol. — Reaction negative. 



Relation to temperature. — Growth more rapid at 35° to 36° C, the entire surface of the agar 

 being covered in twelve hours. 



Bacillus Ginglymus. 



(Fig. 35, PI III.) 



Found at the depth of 1 foot in made soil, which had been paved for several years. 



Character. — Very little growth in atmosphere of hydrogen. 



Morphology. — Slender straight rods with rounded ends, from three to seven times as long as 

 broad. Occurs singly and in short chains of two aud three elements. 



Spores are small, oval, and formed in center of rod. 



Motility. — Peculiar in character. One end of a rod will appear to be fixed, and the rod moves 

 on this as on a pivot. In others the center of rod acts as pivot on which the rod moves backward 

 and fin ward. Some of the chains are motile also, the end rod waving from side to side, drawing 

 the others after it, they showing no movement. It seems as though there was a hinge joint 

 between them. 



Flagella not demonstrated. 



Colonies on gelatin plates. — Colonies seen in twenty to twenty-four hours as minute whitish 

 dots, x 80. Gray granular disks with irregular edges. At end of thirty-six hours the surface 

 colonies have reached a diameter of one-fourth of a millimeter, and are white. The deep are 

 still punctiform. x 80. Surface colonies show central portion of orange brown color, made 

 up of finely interwoven lines, giving a somewhat wavy appearance. Around this is an outer 

 zone of gray with well-defined edges, but showing no particular structure. The deep colonies 



