Dec.i3. igis Angular Leaf-Spot of Cucumbers 473 



and inhibited by all the other strengtlis. 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. Growtla 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 botli 2 per cent and 3 per cent the growth was scanty and fiocculent, 

 composed largely of chains (PI. XLVIII, fig. i), especially in the 3 per cent solution. 



Toleration of acids. — Neutral bouillon containing o.i, 0.2, and 0.3 per cent, 

 respectively, of malic acid, tartaric acid, and citric acid was used. After tliree 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 growtli. 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 op 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 fiocculent 

 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 fiocculent. 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.^ — 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 i c. c. of boiled starch water, i . 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 i c. c. of the standard sodium-nitrite solution and 10 drops of the 

 sulphuric-acid water to each tube. No reaction appeared until the culttires 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 (Dvmham's solution) — about one-third that of Bacillus colt. 



1 Contains litmus, glycerin, milk sugar, and dibasic ammonium phosphate. 



