[HARRISON & BARLOW] SLIME-PRODUCING ORGANISM 107 



Duplicate cultures were incubated at 37° C. and growth took place 

 up to alkalinity — 20°, but not above. The temperature fell a little and 

 pigment appeared in dr S. A ring formed on the tube at the surface 

 of the liquid in — 5° and rfc S. Later the cultures were placed at 20° C. 

 and growth became like those kept at that temperature. 



Conclusions. — Growth took place in bouillons made alkaline with 

 normal NaOH up to — 40° but not when alkaline — 60°. In bouillons 

 neutral or alkaline up to — 10° growth was more abundant than in bouil- 

 lons alkaline — 35° or more. Pigmentation took place in sucrose bouil- 

 lons alkaline up to — 10°, best when alkaline — 5°. Sucrose stimulated 

 growth and greatly aided pigmentation. Growth in alkaline bouillon 

 and alkaline sucrose bouillon reduced the alkalinity and inversion was 

 delayed until the free alkali was neutralized. 



Growth in Acid Bouillons. — Portions of the neutral bouillon 

 already referred to were modified with lactic acid and with lactose 

 to fonn the following media; d= °, +0°, + 6° L, +15°, and 

 -[-15° L, the numerals denoting the degree of acidity and L indicating 

 the presence of lactose. 



The media were inoculated and incubated at 20° C. The -\-°, 

 -j-6°, -\-6°L, were turbid in 24 hours and the turbidity and sediment 

 increased daily for 20 days. There was abundant growth in 15 days 

 but no pigment. In 20 days there was a faint green blue color in -1-6° 

 only. There was no sign of growth in the -|-15° nor in the -]-lÔ°L. 



Conclusions. — Lactic acid was unfavorable for growth and when 

 added to neutral bouillon to the amount of -|-15° prevented growth. 



Growth at different temperatures in beef peptone bouillon containing 

 various amounts of sucrose. 



In the table below the per cent refers to grams of sucrose contained 

 in 100 c. c. of the medium. 



The time indicated is from inoculation, thus, ''Growth retarded 3 

 days" means that until 3 days from inoculation the growth was less 

 than in the bouillon without sucrose. 



