MEMOIRS OF THE NATIONAL ACADEMY OF .SCIENCES. 17 



the corona of the deep colonies is almost twice the diameter of the central portion. There is no 

 liquefaction of the gelatin. 



Agar slant. — A thin whitish layer forms in the. course of thirty-six hours. It has smooth 

 edges ami is marked by yellowish points. After a few days the yellow growth predominates, 

 and an elevated hand 1 mm. high is formed, about salmon color. On the surface it is almost 

 covered with a white mouldy looking growth, which is dry and thin and easily scooped off. Unde r 

 the micros -ope it is seen to be made up of short rods and filaments, many of which show false 

 branching. A tine whitish mossy looking growth is seen pushing into the agar from the under 

 surface of the layer, which appears to be. made up of numberless filaments closely packed. In 

 some cultures the salmon colored layer is absent, the growth being limited to beneath the 

 Surface of the agar, with a white, dry, very thin layer ou the surface. This is easily scraped off, 

 leaving the surface of the agar perfectly smooth. The conditions which cause this difference of 

 growth have not been clearly made out. 



Gelatin stub. — Growth occurs along the puncture and is seen in twenty-four hours, and a 

 white dry looking button forms on the surface, which attains a diameter of ~> nun. by the end of 

 a week. At the same time fine feathery looking offshoots are seen passing out from 

 the puncture. No liquefaction takes place. A very slight brownish discoloration of 

 the gelatin is caused near the surface. 



Potato. — A yellowish growth, marked with whitish points, is formed along the 

 line of inoculation. It is rough and dry looking, and soon becomes thrown into 

 numberless fine folds and wrinkles. It acquires a piukish tinge. Is never very 

 abundant. 



Bouillon. — A thin film with white powdery looking matter on it is formed in thirty- 

 six hours. The liquid remains almost perfectly clear, while whitish flocculi collect at 

 the bottom. 



Bosolic (fid. — Growth very scanty. No change in color. 



Litmus milk. — The milk becomes more blue by the. third day. A thick yellowish 

 ring forms around the tube at the surface. There is no change apparently in the milk itself. 

 Reaction alkaline. 



Sugar gelatin, deep stab. — Growth down stab and on surface, as in plain gelatin. 



Indol. — Reaction negative. 



Relation to temperature. — More rapid growth at 35° to 36° C. than at room temperature. 



Cladothbix Profundus. 



(Figs. 15 and 10, PI. II.) 



Pound at the depth of feet in made soil, which had been paved over for a number of years. 



Character. — Requires oxygen. No growth in an atmosphere of hydrogen. 



Morphology. — Forms long chains and filaments, which show the characteristic false branching. 



Spore formation not observed. 



Motility. — Nou-motilc. 



Flagella not demonstrated. 



Colonies on gelatin plates. — Colouies become visible in from twenty-four to twenty -eight hours 

 as minute circular white dots. At the end of thirty-six hours the surface colonies are one fourth 

 of a millimeter in diameter; the deep still punctiforni. xSO. The deep are made up of very fine 

 wavy lines running radially from the center into the gelatin. The surface colonies are of the 

 same general structure, but the center is too dense to be made out clearly. It is brownish in 

 color, surrounded by a beautiful corona of long, wavy, fine lines, quite regularly disposed. At 

 the end of forty-eight hours the gelatin has taken on a clear brownish hue, and each colony is in 

 a small saucer of liquefaction. As the. surface colonies grow older, the center becomes a mottled 

 brown, but no structure can be made out. Surrounding this is a darker zone, made up of densely 

 matted fillers, from which the corona is given oft'. It is much narrower in proportion than in 

 the younger colonies. A whitish skin, folded in a radial direction, forms after some days on the 

 liquefied gelatin. At the end of five or six days the entire nlate becomes liquefied, if it contains 

 H. Doc. 253 2 



