74 A Bacterial Spot of Citrns 



Acid production. In nutrient broth containing 2 per cent, dextrose, 

 laevulose^ saccharose, lactose and glycerine and in ordinary broth 

 without the addition of any carbohydrate there is no acid production, 

 but the medium in 10 days becomes shghtly more alkaline, but only 

 by 10 degrees or less of Fuller's scale. 



In peptone water tinted with litmus, however, the organism produced 

 acid with several carbohydrates. The following table shows the 

 behaviour of the organism in tubes containing Dunham's solution and 

 various carbohydrates and other substances. 



Dextrose Slightly acid, litmus somewhat reduced 



Laevulose Acid reaction marked 



Galactose Slightly acid, litmus considerably reduced 



Maltose Distinctly acid 



Lactose No change in reaction 



Saccharose Slightly acid, litmus somewhat reduced 



Dextrin No change in reaction, litmus completely reduced 



Starch No change in reaction 



Glycerine No change in reaction 



Mannite Distinctly acid 



Sodium formate No change in reaction 



Sodium citrate No change in reaction 



The bacillus therefore produces acid in the presence of laevulose, 

 dextrose, galactose, maltose, saccharose and mannite, most marked 

 with laevulose. 



Alcohol production. The first distillate from a culture in 2 per cent, 

 laevulose broth was tested for alcohol, etc. The distillate was divided 

 into four portions, to the first was added Lugol's iodine, then a little 

 NaOH solution; on heating the mixture there was a distinct smell 

 of iodoform. The second portion tested with Schifi's reagent gave 

 a negative reaction for aldehyde. To 10 c.c. of a third portion was 

 added 2-5 c.c. 25 per cent, sulphuric acid and a crystal of potassium 

 bichromate. This was distilled, and in the process the bichromate 

 was reduced to a green colour, and the distillate smelled strongly of 

 acetaldehyde and reacted with Schiff's reagent. 



A similar test with distillate from control flask gave only negative 

 results. It is evident therefore that an appreciable amount of alcohol 

 is produced in sugar broth cultures. 



Ammonia production. The distillate from cultures in nutrient 

 broth gave a positive reaction for ammonia with Nessler's solution. 



Indol is produced both in Dunham's solution and in nutrient broth 

 incubated for 10 days at 25° C, but all tests for Phenol were negative. 



