OXYGEN FROM COLOURED BACTERIA. 
135 
am oant of A mount of Time. Oxygen present. | CO, present. 
| Bee. 3 ee. 16 hrs. 193 p.e. | O4l p.c. 
| 5 cc. 3 e.c. 16 , 19:8 p.c. 03 p.c. 
| Bee. 3 c.c. 16 ,, 203 p.c. 2 pec. 
| 100 c.c 20 c.c. 8 ,, 17:09 p. c. 181 p. c. 
20 ce. 10 c.c. 20 , 117 p.e. 3°55 p. c. 
25 e.c. 10 c.c. 28 ,, 9:8 p.c. 25 p.c. 
*50 c.e. 10 c.c. 96 ,, 0-17 p. c. T2 p.c. 
112 grm. 9 c.c. 94 , 13:4 p.c. 2:99 p. c. 
* Contains an exceptionally large amount of Bacteria. 
T From agar-cultures weighed moist. 
The above results show that, confined in a limited supply of air, 
no evolution of oxygen is shown, but the percentage of oxygen 
Present steadily diminishes and finally reaches almost nil, whilst 
at the same time a certain amount of CO, is produced corre- 
sponding to about one-third of the oxygen which has disappeared. 
Ti s peculiarity in the respiration of Bacteria has already been 
pomted out by Hesse. For the solution of our problem this 
“ays nothing, the oxygen which disappears being in all probability 
built up into the substance of the developing Bacteria. 
instead of the above arrangement, the following was adopted :— 
The lower halves of test-tubes drawn out so as to be narrowed 
ta ‘he middle are partly filled with a mass of the coloured Bacteria 
ten from bouillon or agar cultures along with a little fluid. 
throush P of a thick capillary tube a current of H. is passed 
rubbes the test-tube, the mouth of which is closed by an india- 
until a. through which a finely pointed exit-tube passes, 
and the tuk has been driven out, when the narrow part is heated 
is still ube drawn out and sealed whilst the stream of hydrogen 
in hie ts through. The living Bacteria may be examined 
efore cone or they may be killed by HgCl,, either added 
Solution wu or after, by enclosing a tube filled with HgCl, 
inner an N ich after closing is inverted and the contents of the 
sealed t outer tubes allowed to mix. After a given time, the 
and ub © 18 opened under Hg and the contents collected 
examined. 
led maa “riments were performed with tubes containing steri- 
“extract. In such cases, after passing a current of 
