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Five litres incubated in agar-agar at 37° C. yielded 1 colony only—a bacterium.
The following species were identified in this 10 litres of air—Micrococci: Sarcina alba,
sarcina flava, staphylococcus cereus flavus and M. citreus. Bacilli: B. helvolus, B. latericius,
B. fulvus and B. lactis innocuus. Streptothrix: Str. Forsteri.
IX.—On June 3rd samples were taken of the tunnel air between Shepherd's-bush and the
Marble-arch station. They were taken from a platform behind the engine, as in observation IV., and
only while the train was travelling. One sample was taken between Shepherd's-bush and Notting-hill
stations, another between Queen's-road and the Marble-arch stations. The tunnel temperature was
70° F., and the barometer stood at 30 25 in. The carbon dioxide in the tunnel was .104 per cent,
and the organic matter was .0018. The time was 11.15 a.m.
Fresh air samples were taken at 11.40 a.m. under a tree in Hyde-park. It was a dull damp
day following a rainy night. There was a light west wind. Temperature, 64° F. Barometer,
30.20 in. The percentage of carbon dioxide in the air was .039, and the organic matter was .0017.
The results were as follows—
Tunnel air.—Owing to an unfortunate inadvertence both 5 litre samples of this air were
incubated in gelatin at 20° C. They serve, therefore, for the comparison of the air in two
different sections of the tunnel.
Sample A (taken between Shepherd's-bush and Notting-hill) yielded 14 colonies, viz.,
10 bacteria, 2 yeasts and 2 moulds.
Sample B (taken between Queen's-road and the Marble-arch) yielded 19 colonies, viz.,
10 bacteria, 1 yeast and 8 moulds.
The following species were found in the 10 litres of tunnel air—Micrococci : Sarcina lutea,
sarcina alba, staphylococcus cereus albus, M. cremoides, M. candicans, M. citreus, diplococcus
luteus and diplococcus citreus conglomeratus. No bacilli. Yeasts: Torula alba and
saccharomyces cerevisiae. Moulds: Penicillium glaucum, aspergillus glaucus, a species
of mucor and 2 species of undetermined genera.
Fresh air.—Five litres incubated in gelatin at 20° C. yielded only 2 colonies, both
bacterial.
Five litres incubated in agar-agar at 37° C. yielded 3 colonies, viz., 2 bacteria and a
streptothrix.
The species found in this 10 litres of fresh air were as follows—Sarcina aurantiaca,
Micrococcus rosettaceus, Bacillus lactis innocuus and an undetermined species of streptothrix.
X.—On June 10th samples were taken in one of the lifts at Oxford-circus station at 11 a.m.
as it was going up and down. There were fair numbers of passengers, but the lift was not crowded.
Temperature, 66° F. Average barometric pressure, 29.92 in. The carbon dioxide was .152 per cent,
and the organic matter .0042.
The fresh air samples were taken in the doorway of the Oxford-circus station, i.e., on the
pavement of Oxford-street itself, constituting a fair sample of Oxford-street air at a busy time of day.
A considerable crowd collected and had at times to be dispersed. The time was 11.15 a.m. It was
a fine but cloudy day with a moderate north-west wind. Hardly any rain had fallen for two days.
The street temperature was 58° F., and the barometer stood at 29.87 in. The carbon dioxide in the
air was .073 per cent, and the organic matter .0015.
The results were as follows—
Lift air.—Five litres incubated in gelatin at 20 C. yielded 73 colonies, viz., 64 bacteria,
2 yeasts and 7 moulds.
Five litres incubated in agar-agar at 37° C. yielded 14 colonies, of which 1 was a
streptothrix and the rest bacteria.
The species determined from this 10 litres were the following—Micrococci: Sarcina flava
lutea and alba, and an undetermined species of sarcina, staphylococcus cereus albus and flavus,
M. candicans, M. lactis and M. flavus. Bacilli: B. helvolus, B. luteus, B. fulvus, B. aquatilis,
B. lactis innocuus, B. aeris minutissimus and an undetermined bacillus. Ytasts: Torula
alba and saccharomyces cerevisias. Streptothrix: Str. Forsteri. Moulds : Penicillium glaucum
and an allied form; also mucor mucedo.
Fresh air.— Five litres incubated in gelatin at 20° C. yielded 45 colonies, viz., 39 bacteria
and 6 moulds.
Five litres incubated in agar-agar at 37° C. yielded only 2 bacteria.
The species found in this 10 litres were as follows—Micrococci: Sarcina lutea and flava,
staphylococcus cereus albus and flavus, diplococcus citreus conglomeratus, M. concentricus,
M. rosettaceus, M. citreus, M. citreus agilis, M. albicans tardissimus and M. flavus, with a
coccus which I could not determine. Bacilli: B. helvolus, B. luteus and B. carneus.
Moulds: Penicillium glaucum and an allied species.
XI.—On June 14th samples were taken in a passage at Lancaster-gate station, close to the
bottom of the staircase, and not much above the level of the railway. Nearly all the passengers were
going up by the lifts, so there was very little traffic in the passage. The time was 11 a.m. The
thermometer was 640 F., and the barometer 29.85 in. .078 per cent, carbon dioxide was found in the
air, and the organic matter was .0013.
Fresh air samples were then taken by the fountains in Kensington-gardens under a dripping
chestnut-tree. It was pouring with rain ; nearly an inch of rain had fallen during the preceding
24 hours. Temperature 52° F. Barometer, 29.8 in. There was scarcely any wind; what there was
was N.W. .039 per cent, carbon dioxide was found in the air, and the organic matter was *0019.
The results were as follows—
Passage air—Five litres incubated in gelatin at 20° C. yielded 16 colonies, viz., 13
bacteria, 1 yeast and 2 moulds.