18 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



many colonies, and the colonies float in it as small circular islands. Where the plate contains only 

 a few colonies, each may attain a diameter of 3 mm. The liquefied gelatin is brown in color, and 

 the color penetrates the unliquefled portion for about 2 nun. 



Agar slant. — A rough, grayish, glistening band, with irregular beaded edges, is formed in 

 the course of thirty-six hours. As it increases it bends in a transverse direction, and along the 

 line of inoculation becomes finely wrinkled, the edges being thinner and undulating. The surface 

 is a bluish gray and has a metallic luster. The growth takes firm hold on the agar, and forms 

 a tenacious leathery membrane. The agar becomes a clear brown. 



Gelatin stab. — Growth occurs only in the upper part of the puncture, and on the surface a 

 small button forms. By the third day this has begun to sink and from the puncture fine outgrowths 

 are seen. The growth on the surface becomes white, while the gelatin grows brown 

 for some distance down. The depression m the gelatin has vertical walls, as if 

 punched out. The liquefaction is slow and apparently ceases when a depth of 

 about 2 cm. has been reached. The floor becomes level and has some grayish 

 deposit on it. The liquefied gelatin is a clear brown and the color extends some 

 distance into the solid portion below. 



Potato. — No growth is seen until the third day, when a yellowish discolor- 

 ation is noticed. By the next day a finely wrinkled, almost colorless band has 

 formed, and the potato shows a brown discoloration for some distance from each 

 border. It spreads over much of the surface, acquires a grayish hue, and resem- 

 bles a coil of small intestines very closely. It dries after a time into a thin brownish 

 layer, showing many fine wrinkles, having lost the resemblance to intestines. The 

 potato is never much discolored. 



Bouillon. — Growth is confined to the bottom, and around the edges at the surface, while a 

 few flakes of grayish color form on the surface. The bouillon becomes a dark sherry-wine color. 

 Rosolic acid. — No growth apparently. 



Litmus mill;. — No change is noticed for some days, when it becomes violet colo . This is 

 slowly changed, and at the end of six weeks has become a plum color. The casein seems to be 

 dissolved, and a whitish deposit forms on the bottom of the tube. Reaction strongly alkaline. 



Sugar gelatin, deep stab. — Growth is confined to the upper third of puncture and to the sur- 

 face. Liquefaction is much more rapid than in plain gelatin, and there is not nearly so much 

 discoloration. A wrinkled yellowish membrane forms on the walls of the. depression caused by 

 the liquefaction. There is no gas produced. 

 Indol. — Reaction negative. 

 Relation to temperature. — Grows more rapidly at 35° to 30° C. than at room temperature. 



Cladothkix Intestinalis. 



Found in virgin soil at a depth of G feet. 



Character. — No growth in an atmosphere of hydrogen. 



Morphology. — Forms long filaments, which break up into rods of different lengths. The false 

 branching is seen, characteristic of the genus. The filaments have " buds" on them here and there, 

 which are almost spherical. 



Spore formation not observed. 



Motility. — Non-motile. 



Flagella not demonstrated 



Colonies on gelatin plates. — Colonies appear in from thirty-six to forty hours as minute white 

 dots, those on the surface being somewhat larger. x80. Deep arc made up of branching 

 filaments, running from a common center in every direction. On the surface the colonies show 

 a central portion made up of densely packed filaments, the growth being too dense to show the 

 Structure clearly. Toward the edge the filaments are well seen, lying in tangled masses, which 

 break up to form a corona of coarse and somewhat wavy spear points. The color is gray. As 

 the colonies grow older, they become more dense in the center, while the corona of the deep 

 colonies becomes much longer in proportion to the diameter. The filaments are seen to branch 

 distinctly. The surface colonies become white and somewhat mouldy looking, and the gelatin is 



