290 



BACTERIA IN RELATION TO PLANT DISEASES. 



m 



Sufficient acid was produced in 500 cc. [700 cc] of the fluid to carry into solution 2.5 grams of 

 CaO. This acid is not formic, acetic, propionic, butyric, or any other volatile fermentation acid. 

 Neither did lactic, succinic, or oxalic acid occur in any appreciable amount. No amino acids were 

 found. No alcohol and no volatile aldehydes were present. 



Glycerin is fermented in presence of Witte's peptone with production of an acid, but 

 this does not occur in the absence of air. Maltose-bouillon became feebly clouded in the 

 closed end of fermentation-tubes after a week, but growth was so feeble that it was ascribed 

 to impurities in the sugar. Similar results were obtained with mannit. In 1906 the experi- 

 ments with maltose in fermentation-tubes were repeated using the melon-strain of the 

 bacillus in peptone water with a maltose 3 times recrystallized in the Bureau of Chemistry. 

 The result was clouding in the open end and U, but none in the closed end. In beef -bouillon 

 and on steamed potato, in an atmosphere of hydrogen or of carbon dioxide, the organism 

 makes some development but grows less well than in the air (fig. 93). Con- 

 firmatory results were obtained with buried agar-streak-cultures (fig. 94). 



The growth on agar is thin, white, wet-shining, with a distinct margin. 

 The colonies do not grow rapidly. The best growth is usually at the bottom 

 of the streak and in the upper part of the stab. Gelatin (figs. 85, 86), coagu- 

 lated egg-yolk and egg-albumen, and Loeffler's solidified blood-serum are 

 not liquefied. The growth on I^oeffler's blood-serum was thin and poor. 

 There was more growth in Dunham's solution made with Savory and Moore's 

 brown peptone, which contains some muscle-sugar, than in that made with 

 Witte's peptone. In Dunham's solution there was less growth than in corres- 

 ponding tubes of Bacillus amylovorus. An organism identified as Bacillus 

 cloacae grew well in Dunham's solution after B. tracheiphilus had ceased to 

 grow in it. No indol reaction was observed (3 days) nor was any obtained 

 from Dunham's solution after 15 days' growth. 



In McConkey's bile-salt agar there was a moderate amount of smooth, 

 wet-shining, surface growth, and some growth in the top of the stab, but no 

 change in the color of the neutral red (20 days). 



The organism is unable to grow in asparagin-water;t asparagin- water 

 with dextrose; or asparagin-water with dextrose and nutrient mineral salts 

 (asparagin being the only nitrogen compound). The growth in peptone- 

 water (Witte's) with asparagin was not sensibly greater for some weeks than 

 in simple peptone-water, but finally became greater in one tube, which after- 

 ward yielded a pure culture of B. tracheiphilus. This would seem to show 

 that under some circumstances it may get its carbon food from asparagin, 

 but not its nitrogen food. The experiment should be repeated. The organism 

 refused to grow in filtered, boiled river-water containing i per cent sodium 

 asparaginate, i per cent dextrose and 2 per cent glycerin. Neither would it grow in the 

 same medium when ammonium tartrate or ammonium lactate was substituted for the 

 sodium asparaginate. In another experiment, using distilled water, sodium asparaginate, 

 dextrose and glycerin, and inoculating from potato very copiously, it clouded the fluid in 

 the open end of the fermentation-tube slightly after a week, but never made a good growth. 

 B. tracheiphilus will not grow in Cohn's solution, nor in acid (-I-33) peptonized beef- 

 bouillon (acid of the beef -muscle) . It grows in Fermi's solution and in Uschinsky's solu- 

 tion, but rather feebly and with more or less flocculence. Potassium nitrate in peptonized 

 beef -bouillon is not reduced to nitrite. 



The growth of the organism in peptonized beef-bouillon is sensibly retarded by i per 

 p. sodium chloride, and very decidedly by 1.5 per cent or 1.7 per cent. In most 



n 



,86.' 



cent c. 



*FiG. 86. — Streak culture of B. tracheiphilus on gelatin. Drawn from a photograph. Age about 14 days. No 

 liquefaction. 



jRepeated in 1906 with same negative result (20 days at 23° C, approximately). 



