BACTERIAL DESTRUCTION OF COPEPODS 



219 



SESSIONAL PAPER No. 38a 



Sodium Indigo Sulphate Agar Slope. — Luxuriant, raised, moist, spreading, no 

 reduction. In 8 days no reduction. 



Gelatine Stab. — 21° C. 24 hours, growth filiform, equal surface and stab. In 7 days 

 as before; gas bubbles — presumably from the muscle sugar in the beef extract 

 — in tube. In 6 weeks no liquefaction, growth brown, echinulate, medium 

 unchanged. 



Nutrient Broth. — 37 °C. 24 hours. Clouding abundant, medium clearing, flaky 

 sediment at bottom, bluish rim at top. In 3 days flocculent yellowish- white 

 rim at top, easily dislodged on shaking. Medium almost clear. 



Potato. — Abundant along track of needle, glistening, contoured, Isabella colour, 

 growth slightly raised; in 3 days iridiscence perceptible and medium slightly 

 browned. 



Milk. — Coagulation in 24 to 30 hours; curd broken by gas bubbles. In 6 weeks 

 curd contracted, no digestion. 



Litmus Milk. — In 20 hours lilac, much gas, no coagulation; in 36 hours coagula- 

 tion with gassy curd ; in 5 days curd bleached ; in 6 weeks no digestion. 



Aesculin Agar. — Luxuriant, moist, black reaction. 



Neutral Red Bile Salt Agar. — Luxuriant, raised, glistening, moist. Characteristic 

 red reaction. 



Peptone Broth + Aesculin. — Black reaction. 



Gelatine Colonies. — (1st appearance) 5 days at 21°C. Surface colonies up to 1 mm. 



diameter, raised, slightly darker in centre, paling towards edges. Under the 



low power objective homogenous, granular, edges entire. 

 Agar Colonies. — 24 hours at 37 °C. Surface colonies up to 3 mm. diameter, raised, 



concave, glistening, yellowish-white at centre, paling towards edges, edges 



entire, colonies bluish by transmitted light. Under low power objective edges 



entire, finely granular, amorphous. 



Temperature Relations: — 



Thermal Death Point. — 10 mns. exposure in nutrient broth at 60° C. 

 Optimum Temperature. — 37°C. Cultures incubated at 37°, 21°, and 14°C. respec- 

 tively. 

 Vitality on Culture Media. — Active cultures have been recovered from agar after 

 5 months at temperature of 15°-2t)°C. 



Relation to Oxygen. — Facultative anaerobe; glucose agar. 



Biochemical reactions: — 



Indol production: Indol produced. 



Reduction of nitrates : Nitrates reduced to nitrites. 



Voges-Proskauer reaction: Negative. 



Methyl red reaction : Acid. 



38a— 15^ 



