40 



MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



have increased very much, so that the entire mass assumes a round shape. In many there are 

 two foci, as it were, formed by the ends of the trunk where the branching first began. The lines 

 increase for some time, growing longer and becoming more tangled, making the colony more dense 

 in appearance, but even after two weeks they look only like bluish, cottony masses, none more 

 than 1 mm. in diameter, and to the naked eye showing the bipolar arrangement. There is never 

 any liquefaction perceptible. 



Agar slant. — Growth is barely perceptible until the third day, when it is found to have spread 

 quite widely over the surface. It resembles the growth of the bacillus of influenza very closely. 

 Along the needle stroke is a faint colorless line, and ou either side may be seen, by close iuspec 

 tion, colouies which resemble drops of moisture. They are 0.5 mm. in diameter, colorless, and 

 always discrete. The water at bottom shows a whitish growth. After three weeks the growth 

 becomes somewhat more opaque, but never takes ou color, and is always hard to see. It is best 

 seen by transmitted light. 



Gelatin stab. — On second day a faint whitish growth is seen on surface and along the stab. 

 The surface growth spreads until about the sixth day, when it is 3 mm. in diameter, and is irregu- 

 lar in outline and thickness, piling up at the center. It looks as though layer after 

 layer had grown from the center ou the surface of the one preceding, each being of 

 irregular outline, and extending a lesser distance from the common 

 center. It acquires a white metallic luster about the same time. 

 Along the stab tine outgrowths appear about the fifth day, while 

 deeper the colouies appear as separate, minute, white dots, which 

 extend to bottom of puncture. 



Potato. — No growth can be seen until the seventh day, when it 

 acquires a somewhat different color from the potato, which later 

 (sixteen days) becomesabout thecolorof houey. Until the seventh day, 

 only a moisture can be seen. It is a very thin layer, smooth, moist, and looks glazed. 

 Bouillon. — On third day a slight, diffuse cloudiness is seen, which increases somewhat, but 

 never becomes dense. Later the growth settles to bottom, leaving liquid almost clear. 

 Rosolic acid. — Very slight growth and no change of color. 



Litmus milk. — Color is discharged to some extent by the third day. About the tenth day 

 a reddish tint is seen, and the casein is coagulated in tlocculi. Reaction acid. There is no subse 

 quent digestion of the casein up to five weeks. 



Sugar gelatin, deep stab. — No growth seen for a week, when a single colony developed deep 

 white and sending out tine branches. 



Gelatin slant. — At first a faint whitish line, 1 mm. wide, along needle mark. Later this 

 became an elevated white band, 2 mm. wide, with uneven surface and irregular edges. No 

 liquefaction after three weeks. 

 Indol.— Negative. 



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



Note. — In the Zeitschrift fur Hygiene, Vol. VI, page 379, the Franklands first described an 

 organism under the name bacillus Arborescens. The single colonies on gelatin of the bacillus here 

 described correspond so closely to the description of the organism described by them, that I have 

 retained the name so well applied, qualifying it by a striking distinctive characteristic — the 

 tion liquefaction of gelatin. 



Gel. stab. 

 Surface growth 



Bacillus Rodonatus. 



(Figs 41, 42, and 43, PI IV ) 



Found at the depth of 1 foot in made earth, which had been paved for a number of years. 



Character. — Requires oxygen for its best development, though a fair growth occurs in an 

 atmosphere of hydrogen. 



Morphology. — Short rods with rounded ends, but little longer than broad, forming ovals. 

 Resembles the bacillus Prodigiosus very closely. Occurs singly ami in irregular groups; no chains 

 formed. 



