1150 
Aesculin and indican are not decomposed. 
Urea is only splitted by Mycobacterium album. 
In feebly acid media the growth is inhibited ; it is best in neutral 
or feebly alkaline solutions. 
At the oxidation of paraffins, organic acids, probably fatty acids 
are formed as intermediary products; they are, however, only 
present in slight quantities and evidently are oxidised almost as quickly 
as produced. Acid formation from paraffin could, however, be shown 
with the help of washed agar plates to which a little congo red 
had been added, or in which some calciumfosfate was precipitated. 
In the former case blue fields appeared under the inoculation streaks, 
in the latter clear ones. 
Velocity of the petroleum and paraffin oxidation. 
The velocity with which Mycobacterium album, M. rubrum, 
Micrococcus paraffinae, and B. fluorescens lquefaciens oxidise 
petroleum, was ascertained by weighing the quantity of carbonic 
acid formed in a certain time. The diminution of the petroleum 
could not be directly stated as it always evaporates. 
The quantity of the produced carbonic acid was ascertained as 
follows. 
As culture vessel was used a one liter ERLENMEIJER flask provided 
with a ground glass stopper, bearing a vertical glass tube, reaching 
to near the bottom, and a side tube. It was filled with + 200 em* 
of a sterile culture liquid, consisting of distilled water, anorganie 
salts, and 2 em*. sterile petroleum. 
The vertical glass tube was connected with a large U-tube filled 
with soda lime; the side tube was joined to an apparatus succes- 
sively formed by U-tubes, filled with sulfuric acid, beads and paraf- 
finoil (to keep back the petroleum vapour), calciumehlorid, potash 
solution to weigh the carbonic acid, and calciumchlorid for control, 
with a KörrinG pump at the end. When the cock of the pump is 
opened a current of air, freed from carbonic acid, passes through 
the fluid and yields the dried carbonic acid, formed in the culture, 
to the potash tube. 
During 24 hours are formed in the culture, if infected and placed 
at 28° C., Milligrs. carbonic acid by: 
Mycobacterium album 55 
Mycobactertum rubrum 41 
M. paraffinae 34 
B. fluorescens liquefaciéns 27 
Crude culture 93 
