128 DR. A. J. EWART ON THE EVOLUTION OF 
| 
| 
| 
O evolved 
. per grm. 
Name. Wart Grown on: Pigment. Bacteria 
gat. (moist 
weight). 
Micrococcus agilis ...| 0'6 grm. Faintly acid Only in small | 0:023 c.c. 
Bouillon. amount. 
» » | 05 , Bouillon at | Colourless. 0:0 cc. 
first at 35° C. 
» » e| 025, Agar. | Abundant. 0:137 c.c. 
Sarcina rosea......... 065 ,, Faintly acid | But little. 0:021 c.c. 
Bouillon. | 
» ty reme 06 ,, |Neutral Bouillon. Mod. abundant. | 0086 c.c. 
» Do reres 0:25 ,, Agar. | Normal. 013 e.c. 
Sarcina lutea......... 05 , Slightly acid | Colourless. 00 ce. 
Bouillon. | 
” 1) eee O5 ,, | Neutral Bouillon. | Mod. abundant. | 0°051 c.c. 
" py erreren: 05 , Agar. | Normal. 0:066 c.c. 
Sarcina aurantiaca .| 0°35 ,, Bouillon. Mod. abundant. | 0'11 c. 
» » J105 ,, Agar. Normal. (0-14 cc. 
Bacillus cinnabareus. 03, Bouillon. | Fairly abundant. 011 ee. 
” ” 0:3 » » | » | 0:104 c.c. 
» » 0'43 ,, Agar. | Normal. 0:144 c.c 
Staphylococcus citreus, (745 ,, » | » (0118 ec 
Diplococcus roseus ...| 08. ,, » | » | 0:128 c.c 
Bacillus brunneus ...| 04. ,, Starch-paste. | » 0319 ec 
” ” eee 05 ” ” | ” 0:127 e.c 
” ” eee 06 ” Agar. | ” 0:16 e.c 
» » ..|08 , » | » |018 c.c 
Where the pigment is poorly developed the power of evolving 
oxygen is also slight. Cultures of Bacillus brunneus on potatoes 
and starch-paste appear to be as deeply coloured as when grown 
on agar, but show a weaker evolution of oxygen in the former case 
than in the latter. 
Cultures killed by treatment with ether or by heating to 
80° C. for an hour, may still possess a considerable power of 
absorbing and then evolving oxygen. Thus the Bacteria from a 
bouillon-eulture of B. brunneus, after being heated to 80° C. 
for one hour and then exposed to air for a day, could evolve per 
gramme of Bacteria 0:18 c.c. of oxygen in one case and 012 c 
in another. If, however, the cultures had been heated to 90° C. 
for one hour and then left fora day, per gramme of Bacteria 
only 0'065 c.c. of oxygen was evolved. If the heating takes 
place in water the Bacteria may be killed without the absorptive 
power of the pigment being much affected. Thus a mass of 
B. brunneus from agar-cultures, after being killed by heating t? 
80° C. for one hour and then shaken up well with air for seve 
