May 2,1921 
A Bacterial Budrot of Cannas 
151 
the following results: Growth in +32 malic acid, +37 citric acid, and 
+ 35 tartaric acid; no growth in +33 malic acid, +40 citric acid, and 
+ 37 tartaric acid. 
Toleration of sodium chlorid. —Tests were made in +15 peptone 
bouillon to which were added 1, 2, 3, 4, and 5 per cent sodium chlorid. 
Prompt clouding, becoming heavy, appeared in 1 per cent, and fairly 
prompt moderate clouding appeared in the 2 per cent. The growth in 
3 per cent was delayed and took the form of cobwebby, viscid, persistent, 
streamers without clouding. These streamers were not made up of 
chains but of single or paired organisms. No growth occurred in the 
presence of 4 or 5 per cent sodium chlorid, 
Other cultural features. —Growth is not retarded in bouillon over 
chloroform. Nitrates are strongly and promptly reduced. No indol is 
formed (10 days to 2 months). Hydrogen sulphid is produced in 
peptone-beef bouillon. Ammonia production is strong. The odor of 
most cultures is rather disagreeable. 
Temperature relations. —The optimum temperature for growth is 
about 35 0 C. No growth takes place in peptone-beef bouillon (+15) 
below 5 0 nor above 40°. In one test there was very weak growth at 
40°. The thermal death point is 52 0 . 
Effect of freezing. —When transfers from young +15 peptone 
bouillon cultures are frozen solid and kept frozen for 15 minutes, then 
thawed and plates poured with measured loops just as before freezing, 
the colony counts show that from 50 to 90 per cent are killed. 
Effect of desiccation. —The organism is very sensitive to drying. 
Drops of 1- to 6-day-old bouillon cultures were dried on cover glasses 
in sterile Petri dishes in the dark. These covers transferred to bouillon 
after 2 days’ drying gave prompt clouding; after 3 days less than half 
gave growth, and after 5 days no growth was obtained. 
Effect of sunlight. —The organism is very sensitive to sunlight. 
Agar poured plates, one-half covered with black paper, were exposed 
to bright sunlight bottom side up on ice in November at 11.30 a. m. 
When counted 5 days later, colonies were numerous on the covered side. 
On the exposed side there was noticeable reduction after 1 minute’s 
exposure; 75 per cent were killed after 2 minutes, 95 per cent after 3 
minutes, and all were killed after 4^ minutes’ exposure. 
Vitality on culture media. —The most long-continued growth is 
made in milk, peptone-beef bouillon, and peptone-beef agar. At room 
temperatures the organism will live in these media for 6 or 7 months, 
or until the medium is almost completely evaporated. Cultures in these 
media kept in the ice box for 1 year give prompt growth when transferred. 
