OXYGEN FROM COLOURED BACTERIA. 141 
it is held by hemoglobin, but differs in so far as the loss of 
the absorbed oxygen does not involve any perceptible change in 
coloration. 
The storing of oxygen by these coloured Bacteria must have 
some biological significance in their economy. At first sight it 
seems as if we had here a very plausible explanation of the 
phenomena of at least facultative anærobism and even of obligate 
anerobism also, and an explanation moreover coinciding with 
that originally given by Pasteur. Lehmann and Neumann state 
that 8 of the coloured Bacteria, all of which are normally 
completely ærobic, may develop under certain conditions as 
anerobes. It is possible that the explanation of this phenomenon 
might be due to the bacterial colonies being supplied with a 
store of reserve oxygen. Further consideration, however, points 
against this explanation. Thus the amount of oxygen stored up 
ls relatively small and is, as has already been shown, used up by 
the respiration of the Bacteria in the course of 24 hours or so. 
Nevertheless the possibility remains that oxygen might still be 
present, held in a more strongly combined condition, which can 
be detected by none of the methods above described, but which 
18 still available for the life and respiration of the Bacteria, and 
that this oxygen might suffice for the respiratory needs of the 
Bacteria When growing as anzrobes. 
Bacillus brunneus will not grow in an atmosphere of either H. 
or CO,, If colonies are allowed to develop on roll cultures on 
gelatino at 20° C. until they are clearly visible as small brown 
tein replacing the air in the culture-tubes by hydrogen all 
the b growth ceases, i. e. the amount of oxygen stored up 1n 
acterial colony is insufficient to allow of its continuing to 
stow m an apparently anærobic manner. 
catagories on the respiration of B. brunneus were 
divided M A the following manner :—A bouillon-culture 1s 
Bacteria á "d equal portions containing equal amounts of 
a smal] lass c.c. being placed along with 10 c.c. of air in 
Afer à y ulb, the bent neck of which is closed by Hg. 
Sven length of time the enclosed gas is collected 
Over H 
obtained analysed. The following are the results thus 
