Dec. 131 *9*5 
Angular Leaf-Spot of Cucumbers 
473 
and inhibited by all the other strengths. The experiment was repeated using 2,3, 
and 4 per cent of sodium chlorid. Again, the 2 per cent retarded growth (clouding 
on the fourth day). Checks clouded after 24 hours. Growth appeared in the 3 per 
cent after 12 days, but there was no growth in the 4 per cent even at the end of four 
weeks. In both 2 per cent and 3 per cent the growth was scanty and flocculent, 
composed largely of chains (PI. XLVIII, fig. 1), especially in the 3 per cent solution. 
Toleration of acids. —Neutral bouillon containing 0.1, 0.2, and 0.3 per cent, 
respectively, of malic acid, tartaric acid, and citric acid was used. After three days 
the 0,1 per cent cultures of all three acids were well clouded; the 0.2 per cent malic 
and tartaric acids were all moderately clouded, while the 0.2 per cent citric acid 
showed no growth. None of the 0.3 per cent cultures were clouded. After three 
weeks the 0.2 per cent citric acid was well clouded, but in no case did the 0.3 per cent 
cultures show any growth. The cultures were watched for five weeks. 
Toleration of alkali. —The organism is quite sensitive to alkali. Peptonized 
beef bouillons titrating, according to Fuller’s scale, +25, +20, +10, +5, o, —5, —20, 
and —30, were inoculated from a 4-day bouillon culture, using a carefully measured 
3-mm. loop for each tube. After 24 hours all showed growth except the —20 and —30. 
Heaviest growth occurred in the +25, weakest growth in the —5, which was flocculent 
instead of clouded. Five days later the same relative growth was evident throughout 
the series, but the —5 had become clouded and the —20 weakly flocculent. The —30 
remained clear. After two weeks there was moderate growth in the —20, but none 
in the —30. The alkali used was sodium hydrate. 
Uschinsky’s solution. —In Uschinsky’s solution growth is heavy, with a heavy 
membranous pellicle which falls readily as a whole. Greening of the media begins 
at the top on the second or third day and proceeds rapidly downward until the whole 
is a decided pale apple green. The medium does not become viscid. 
Fermi’s solution. —At the end of 10 days a fine green fluorescence like that in 
Uschinsky’s solution is visible. No fluorescence appeared in tubes of Cohn’s solution 
inoculated on the same date for comparison. 
Cohn’s solution. —There is good clouding, heaviest near the top, but without a 
pellicle. Numerous floating crystals occur and the white precipitate is dotted with 
crystals. No greening occurs. 
Sugar agars. —No yellowing occurred on any of the sugar agars used. Cultures 
were made on beef-peptone agars containing, respectively, 2 per cent of saccharose, 
maltose, and dextrose, and in sugar agar without beef—i. e., containing only peptone 
and saccharose. The cultures were watched for eight weeks, during which time they 
remained white. 
Dolt’s synthetic agar . 1 —Growth is abundant, covering the surface on the third 
day with a thin pink layer. Reddening of the dark agar begins on the second or third 
day; and after 10 days the color is changed throughout, although the lower half has 
not lost completely its purplish hue. 
Bouillon over chloroform. —Growth is not retarded in unshaken tubes of 
peptone-beef bouillon to which 5 c. c. of chloroform have been added. 
Reduction of nitrates. —Nitrates are not reduced. Five-day-old cultures in 
nitrate bouillon were tested by the addition to each of 1 c. c. of boiled starch water, 1. c.c. 
of potassium-iodid water, and 10 drops of sulphuric acid. There was no color reaction. 
Indol. —There is a weak indol production in 2 per cent peptone water and in pepton¬ 
ized Uschinsky’s solution. Tests were made at the end of the fifth and tenth days 
by the addition of 1 c. c. of the standard sodium-nitrite solution and 10 drops of the 
sulphuric-acid water to each tube. No reaction appeared until the cultures were 
heated to 70° C., when a feeble but decided pink color appeared. The checks gave 
no pink reaction. A better reaction was obtained in peptone water containing 0.5 
per cent of sodium chlorid (Dunham’s solution)—about one-third that of Bacillus colt. 
1 Contains litmus, glycerin, milk sugar, and dibasic ammonium phosphate. 
