348 BACTERIA IN RELATION TO PLANT DISEASES. 
strict aerobe, except in the presence of maltose or some unknown substance sometimes 
contaminating the maltose; a matter open to further inquiry. Cane-sugar is inverted. 
Oxydase and peroxydase are absent, 7. e., cultures give no reaction with guaiac resin 
in alcohol, nor on addition of hydrogen peroxide. ‘Tyrosinase perhaps occurs, 7. ¢., 
the substance causing the brown stain. Catalase is present, 7. e., some body yielding a 
copious evolution of gas when hydrogen peroxide is added to old potato cultures. This 
substance is destroyed at 85° C. 
Large doses of grape-sugar or cane-sugar in slant agar retard growth at first (9 per 
cent grape, 17 per cent cane) and then stimulate it greatly. On 10 grams of recently slanted 
nutrient agar containing 3 grams of grape-sugar no growth was obtained. 
A small amount of non-volatile acid is developed out of -various sugars—grape-sugar, 
fruit-sugar, cane-sugar, galactose, maltose; and in old cultures on the following substrata: 
carrot (occasionally), rutabaga, sweet potato, sugar-beet. 
The steam from old cultures in hyacinth-broth caused a 
copious rusty precipitate when conducted into Nessler’s 
solution, indicating the presence of ammonia or amins. 
This organism grows readily on all ordinary culture- 
media except when it is too salt or too acid. It is very sensi- 
tive to acids, even those in the parenchyma-juice of the 
hyacinth retard growth (clouding) decidedly (14 days, 16 
days, or more). Growth did not take place in potato-broth 
(+30), in juice of slow-growing cabbage leaves (+49), cauli- 
flower-broth, sugar-beet juice diluted with water, or juice of 
green or ripe tomato-fruits (+59 and +64); growth was also 
much retarded in acid beef-broth (+40). The bacterium 
would not grow in beef-broth concentrated by boiling (+80). 
When the acidity of the +30 potato-broth was reduced 
slightly (+28, +26), by sodium hydrate, growth took place. 
Growth in beef-broth was retarded (5 to 7 days) by 1.5 
per cent c. p. sodium chloride. 
It does not grow well in Uschinsky’s solution; in this 
medium there was either no growth or it was long delayed and 
feeble (and without much yellow color) unless peptone was 
added to it, in which case growth was centupled. 
within a few days, but reoxydized quickly on shaking, and 
was bright blue on the death of the organism, the bacterial 
precipitate being unstained. Indigo carmine in Dunham’s 
solution changed from a dull blue to a bright blue and retained this color for a long time, 
but finally became yellowish. Rosolic acid in Dunham’s solution with enough c. p. hydro- 
chloric acid to render the medium yellowish did not redden but became colorless; the bac- 
terial precipitate, on the contrary, became rosy or salmoncolored. Acid fuchsin in Dunham’s 
solution bleached slowly, the color being all gone in about 4 weeks. Litmus in various 
media was bleached very slowly, the reduction being evident usually only at the close of 
the second or third week. 
The optimum alkalinity for growth in peptonized beef-bouillon lies between o and +15 
of Fuller’s scale; the maximum tolerated alkalinity (sodium hydroxide in bouillon) is more 
than — 20 and less than — 40; in bouillon the tolerated acidity is about +30 (malic acid) 
Fig. 145.* 
*Fic. 145.—Behavior of Bact. hyacinthi in a fermentation-tube containing water, 1 per cent Witte’s peptone, and 
I per cent maltose (the latter 3 times recrystallized). Culture cloudy in open end and clear in closed end after 8 days 
at 24°C. Nogas. Drawn Dec. 18, 1906. 
Methylene blue in Dunham’s solution was reduced © 
i ae 
