9 6 
Journal of Agricultural Research 
Vol. VIII, No. 3 
granular in the center; margin of buried colonies sharply defined; liquefaction of -f io 
gelatin moderate to rapid; circular white colonies with regular margins on gelatin 
plates, visible in 18 hours at 30° C., in 26 hours at 21 0 to 23 0 C.; on thin-sown gelatin 
plates colonies grow rapidly and are frequently 2 centimeters in diameter at the end 
of fourth day at 22 0 C.; alkaline reaction in gelatin cultures to which litmus has 
been added; on sterilized potato slow white to yellowish white growth; characteristic 
rapid white growth and black stain on raw potato (when streaked from agar); grows vig¬ 
orously and with great rapidity on all neutral and feebly alkaline media; clouds 10 cc. 
of +15 bouillon in 6 hours at 30 0 C. and in 24 hours at 13 0 to 14 0 C., when inoculated 
with one 3-mm. loop from a bouillon culture 4 days old at 24 0 C.; especially good 
growth on neutralized potato-juice gelatin in which stab-cultures rapidly develop a 
funnel-shaped liquefaction, but less rapid in my hands than in +10 peptonized beef- 
gelatin; gradual clouding of salted peptonized beef-bouillon, and production of 
chains therein and pellicle on undisturbed old cultures; no indol reaction; tolerates 
in beef-bouillon a considerable amount of sodium chloride (5 per cent) and of sodium 
hydrate (+50); very active growth in potatorjuice with formation of thick pellicle 
and heavy precipitate; rapid clouding of closed end of fermentation-tubes containing 
potato-juice, but no production of gas; no growth in Cohn's solution; slight greenish 
tinge in Fermi's solution on long standing; moderate production of hydrogen sul‘ 
phide ; distinct and persistent nitrite reaction in nitrate bouillon but no gas; grows in 
peptonized beef-bouillon from —50 to +16 and beyond, also in potato broth acidulated 
to +46 with citric acid, but no growth when acidulated to +45 with oxalic acid; slow 
(acid) coagulation of milk with precipitation of the casein; slight reddening and final 
reduction of litmus in milk; slight production of gas in shake-cultures in some beef- 
agars; grows in bouillon over chloroform; in streak-cultures it reddens litmus agar 
decidedly in 48 hours at 20° C. in presence of either dextrose, saccharose, lactose, 
gelactose or maltose; it blues plain litmus agar decidedly in 48 hours and does not 
promptly redden the same with addition of dextrine or glycerine; no reddening of 
litmus in gelatin-cultures; the acid persists on boiling; produces small quantities of 
gas from innosit (muscle sugar), lactose and mannit; optimum temperature 28° to 30° 
C.; little growth below 4 0 to 5 0 C.; minimum temperature for growth in +15 beef 
bouillon i° C. or under; maximum temperature for growth in +15 beef-bouillon about 
36° C.; thermal death-point in +15 beef-bouillon 47 0 C.; 90 per cent destroyed by 
freezing in bouillon. Appel reports loss of virulence in some of his cultures, but I 
have not observed any during a period of three years. * * * The following are 
recommended as quick tests for differential purposes: Very thin sowings on gelatin 
plates; streaks from agar to sterile raw potato; behavior in blue litmus milk; behavior 
in nitrate bouillon and in Cohn’s solution. The right organism should produce big, 
round, white colonies promptly on thin sown gelatin plates, and should rot potato 
tubers promptly. 
BACILLUS SOLANISAPRUS HARRISON 
The following is a brief of Harrison’s original description of this 
organism (17). No effort has been made to follow the original form, but 
care has been taken to preserve accuracy of statement: 
Bacillus, with slightly rounded ends, variable in size, according to the media and 
temperature in which it was grown. From freshly infected potato stems and tubers 
it varies in size from 1.5 to 4/x long and about 0.6 to 0.9,1* wide. From beef-peptone- 
agar cultures 24 hours old at 20° C. the bacteria were short and stout, rather variable 
In length, ends rather square but rounded, vacuolated with average dimensions 1.2 
by 0.611. From beef-peptone gelatin +5, 24 hours old at 20° C. the bacilli were 
short and stout, ends slightly rounded, some vacuolated, dimensions 1 to 2.5 by 0.6 
to 0.8 fx. Involution forms, long swollen bent rods in 24 hours at 37 0 C.; endospores 
