456 MEMOIES OF THE NATIONAL AOxVDEMY OF SCIENCES. 



Bacillus capillaceus. 



Isolated from the. water of tbe Scbuylkill Kiver. Not coninioii. A large viotile bacillus vrhh 



square or bhiiit eiuls. growing into segmented threads; it has a number of flagella; forms oval 



spores, which develop in tlie centers of the short rods or segments. (See fig. I'J.) 



.•■■■■■; Colonies in (jelatin. — On the surface, about the second or third day, saucer-shaped 



iQi liquefactions of a hazy appearance, 2 mm. or so in diameter and growing larger, may 



•...-■■ l^c «<?en. They are denser and grayish at their centers, and their margins are well- 



FiQ.19 tlefined as grayish circles. Deep colonies are seen to consist of small spheres aud hazy 



spots. The liquefied areas, under the low power, are dark, dense, and granular (PI. II,. 



fig. 4), with darker clumps at the centers and at the peripheries a fringe of radiating fibrils. A 



circulating motion may be seen in them. In some cases the liquefied gelatin seems to contain 



broken filaments. When the deep colonies are examined with the low jiower great variation is 



seen in their appearance. (PL II, figs. 6, 7, aud 8.) The most common colonies are rounded, 



dark, and granular, with a few fibrils projecting into the gelatin; other colonies, and 



the most characteristic, are irregular radiating or stellate branching figures, formed of 



columns of small "daughter" colonies and filamentous outgrowths. Between these 



and the simpler forms there may be found all grades of transition. The deep colonies 



seem to send out more and more numerous fibrillar processes into the gelatin and 



cause its liquefaction. After a few days the areas of liquefaction contaiu grayish, 



felt-like layers. 



Gelatin *•<«?*.— Liquefaction in saucer form, extending to the tube wall and slowly 

 downward with a nearly level floor. (See fig. 20.) There is only a faint development 

 along the line of inoculation. The liquefied gelatin after a time contains flocculi and 

 has a wrinkled pellicle at the surface, which is partly sunken in the gelatin. At the 

 bottom of the licjuefaction there is a flocculent whitish sediment. In cultures of 

 several weeks this may be much increased in amount and of a sheet-like character, 

 apparently due to the repeated formation of mycoderms at the surface and theii- 

 consequent sinking. 



Acid gelatin.—i^ome growth: seems to produce an alkaline reaction. 



Fig 20 



Agar s/«h^— Grayish, dense, rather widely spreading layer, with wavy, sharply 

 defined margins. At first the surface is like frosted glass, but later it becomes smooth and 

 shining, and may show a few slight wrinkles; the agar acquires a brown-green color. 



BoiiilloH.—Cleur; at the bottom a sediment of sheet-like mas.ses and a collection of similar 

 material at the surface; the reaction is alkaline; a mycoderm may form which falls to the bottom 

 very readily. 



Fotctto.— Thick, rough, granular, widely spreading growth; it has more or less of a purple- 

 pink color, becoming later grayish; the growth on potato is characteristic. 



Litmus «u7/.-.— Decolorized and coagulated; a deep layer of cloudy serum above and a bluish 

 ring on the tube wall; the clot is somewhat jelly like; the reaction is neutral. 



Siujar (jdatin in dee [j stab.— Good growth of discrete and confiuent minute colonies; no gas 

 production nor liquefaction. 



Rosolic acid. — Apparently no growth. 



Indol production.— F&mt or doubtful; addition of nitrite solution is necessary. 



Relation to temperature.— Gvows. at the temperature of the room and at 35° to 36°. 



Bacillus delabeus. 



Isolated from the water of the Schuylkill Eiver. Common. A rather small motile bacillus, 

 with rouuded ends, occurring in short rounded and long forms. and in pairs; it has a terminal 

 tlagellum; no spore formation observed. 



Colonies in f/elatin. —Ahont the second day the surface colonies are thin, translucent, shining 

 expansions, with wavy, irregular, sharply defined outlines and grayish centers. Under a low 

 magnifying power the colony is thin and translucent, and the surface is marked by numerous 

 delicate lines winch run in various directions, and which sometimes branch. (See PL I, fig. 12.) 



v_y 



