472 Journal of Agricultural Research voi. v, no. h 



Gelatin stabs. — At 15° to 18° C. in +10 peptone gelatin the siu-face growth 

 after seven days is about 6 mm. in diameter, with a pit of liquefaction 2 mm. wide and 

 2 mm. deep. Stab growth is granular, not villous, fading out downward. As lique- 

 faction progresses the upper part becomes stratiform, the lower part blimtly funnel- 

 form (PI. XLIX, fig. 3). Liquefaction progresses rather slowly but is complete within 

 three to fom- weeks at the specified temperattues. 



Beef bouillon. — In +15 peptone-beef bouillon uniform clouding occurs within 24 

 hours. This clouding is weak to moderate, never strong. On the second day a mem- 

 branous pellicle is formed, which fragments and falls readily on shaking. It is made 

 up of a homogeneous mass of bacteria — i. e., free from pseudozoogloeae but containing 

 a few short chains (10 or 12 individuals). Old cultures (4 to 6 weeks old) are often 

 decidedly green fluorescent. The white precipitate breaks up readily on shaking 

 and contains many small crystals. 



Potato cylinders. — When inoculated from agar cultures growth on steamed 

 potato cylinders in two days is moderate, spreading, creamy white, shining, and 

 slimy. The part of the potato out of the water becomes slightly browned. Growth 

 on potato soon ceases. After 10 days the color of the potato is completely changed, 

 becoming a pale bro-\vnish hue, and the growth takes on a similar color (very pale 

 brownish). Tested with alcohol iodin for starch, such cultures give a hea\-y dark- 

 purple reaction, showing that there has been only a partial digestion of the starch 

 (formation of amylodextrin). The cylinders are not softened. 



Milk. — Inoculated milk clears slowly and without coagulation. Clearing begins 

 within a week, and after two weeks tubes of it are translucent so that the outlines 

 of a pencil back of the milk may be seen through it clearly. Cultures i month old 

 are still clear but are then tawny olive,' with a darker rim where the milk has dried 

 down. 



Litmus milk. — Lavender-colored litmus milk begins to blue from the top down- 

 ward on the second day and is completely blued by the third day, without a sign 

 of coagulation or clearing. A decided creamy-white pellicle is formed. 



After 10 days clearing begins and is complete in 20 days. Later the blue color 

 bleaches out (reduction phenomena), beginning at the bottom, leaving the whole 

 fluid a clear (translucent) brown. At no time is there any reddening of the litmus 

 or any coagulation of the milk; nor are any crystals formed in it. 



Fermentation tubes. — The tests in fermentation tubes were made in water 

 containing 2 per cent of Witte 's peptone , to which was added 2 per cent of the carbon 

 compotmd to be tested — namely, saccharose, dextrose, lactose, maltose, glycerin, 

 and mannit. Clouding occurred in the open end of each on the second day, heaviest 

 in the tubes containing saccharose and dextrose, but the closed end in every case 

 remained clear, with a distinct line across the inner part of the U . WTien 5 days 

 old they were tested with neutral litmus paper. Saccharose and dextrose gave a 

 decidedly acid reaction, while all the others were neutral. When 20 days old the 

 saccharose and dextrose were still acid and the others weakly alkaline. No gas was 

 formed and no growlh occurred in the closed end of any. 



No gas was formed in fermentation tubes containing sterile milk; nor was there 

 any separation of the curd. The milk in the open end cleared gradually, while 

 that in the closed end remained imchanged. The litmus reaction was alkaline in the 

 open end. 



Nitrate bouillon in fermentation tubes gave a good clouding in the open end, none 

 in the closed end, no gas, and no nitrate reduction. A decided alkaline reaction was 

 obtained with neutral litmus paper. 



Toleration op sodium chlorid. — Neutral peptone-beef bouillons containing 2, 5, 

 6, and 7 per cent of chemically pure sodium chlorid, respectively, were inoculated 

 from yoimg bouillon cultures. Growth was retarded by 2 per cent of sodium chlorid 



1 Rjdgway, Robert. A nomenclature of colors . . . 129 p., 17 pi. (partly col.). Boston, 1886. 



