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a remark which might be taken to imply the speaker's belief that the condition of his goods was
exceptional, and that the cheap aerated waters made in Stepney were not as a rule above criticism.
Dr. Thomas, the medical officer of health of Stepney, has kindly analysed a couple of samples of these
cheap waters for me, but the results obtained do not indicate the presence of impurity.
I was told by an English maker, in Stepney, that there is a special tendency for "sweet goods"
to become "piecey," as he expressed it, and he added that he had had much trouble at one time, but
had overcome his difficulties by making use of a different sort of sugar. I examined a number of
bottles bearing the names of well-known firms but did not find any "piecey" bottles, or indeed any to
which exception could reasonably be taken on the ground of there being visible turbidity. I have,
however, noticed that the sweet lemonade of an English maker is apt at times to present
considerable numbers of visible particles.
Microbes in aerated waters.
The opinion appears to be widely entertained that the process of submitting water to aeration
is destructive of germs; that in fact water after being charged for some time with carbonic acid
is practically free from micro-organisms. This view has, no doubt, contributed largely towards
popularising the use of aerated waters, and it is not a little surprising—having regard to the
results obtained by investigators—to find that it is so generally accepted. A comprehensive inquiry
into the matter was made some years ago by Dr. Slater, and a brief summary of a paper contributed
by him to the "Journal of Pathology and Bacteriology," vol. i., 1893, p. 469, may here be given.
It appears Sohnke showed in 1886 that the number of organisms in aerated water underwent
diminution when the bottles had been kept for a long period (1-9 months), and that such waters,
when examined 3-4 years after bottling, were practically sterile. Leone concluded that the diminution
in question was not due to displacement of oxygen, but rather to the presence of carbonic acid.
Hochstetter was inclined to question the germicidal action of carbonic acid; in ten of the
24 fresh samples which he examined he found from 10,000 to 70,000 or more micro-organisms
per c.c. Reinl found great variations in the number of organisms in different samples.
Dr. Slater's own observations showed that eleven samples, examined within 24 hours of aeration,
presented from 354 to 2,919 micro-organisms per c.c.; that nine samples, examined from 48 hours
to 7 days after aeration, presented from 51 to 2,615 micro-organisms per c.c., and that ten
samples, examined three weeks or more after aeration, presented from 3 to 2,000 micro-organisms
per c.c. The microbes found were for the most part bacilli, micrococci being less common, yeasts
rare, moulds very variable in number, but on the whole more common in small bottles than in syphons;
the proportion of liquefying organisms was never large.
Dr. Slater selected samples prepared from waters of different kinds, the ordinary London river
and deep well supplies—artesian well waters—distilled water and boiled water. He found that "the
differences in the source of water supply or the purifying treatment it undergoes can scarcely
be traced in the finished water" and hence he concludes that "bacterial examination gives
no information as to the original purity of the sources of supply." He tested the behaviour
of various pathogenic organisms when kept in bottles of aerated water and found the spirillum choleras
of Koch and the spirillum described by Finkler and Prior as occurring in cholera nostras, very little
resistant; staphylococcus pyogenes aureus was rather more hardy; bacillus typhosus and bacillus coli
communis remained viable about a fortnight, and bacillus liquefaciens fluorescens was recoverable
from the water after five weeks. The action of the pressure factor he regarded as unimportant, the
organisms dying as quickly in water thoroughly saturated with gas as they did in water in which the
gas was under pressure. The observations of Scala and Sanfelice are, Dr. Slater notes, in agreement,
with this conclusion, though these observers pointed out that water thoroughly saturated with gas was
more destructive to micro-organisms than water not saturated.
Slater lays stress on the fact that the decrease referred to was most noticeable after three weeks,
and he points out that although of general, it is not of constant, occurrence. It is due, he says, to the
presence of carbonic acid, loss of the gas being followed by increase in the number of micro-organisms.
"The bacteria therefore are not in all cases killed, but have their development arrested." Slater
concludes that" aeration undoubtedly increases the safety of water," and that it "offers a practically
absolute safeguard against cholera," though it affords less complete security against enteric fever ; he
remarks that if obtained" from a good source and kept for more than fourteen days"* the water would
"appear to offer complete safety from the usual water-carried diseases." In long-kept waters
Slater says it is usual to find a few moulds, occasionally a colony of bacillus fluorescens liquefaciens,
and variable and sometimes large numbers of colonies of baoillus luteus, an organism specially
resistant to aerated water.
In the case of the observations just referred to, the water employed in the process of manufacture
was derived from a public supply or from a deep well, and in some instances the original water had undergone
treatment with a view to its further purification. It is interesting to turn, therefore, to the results
obtained in India, inasmuch as in some instances the water used was apparently of a far less satisfactory
character than London water. In a paper "On Microbes in Soda Water" in the Indian Medical Gazette of
December, 1893, p. 401, Hankin gives the results of investigations made in Agra. In several samples
of aerated water examined, in which there was question as to the purity of the original source
of water supply, the numbers of bacteria found were much larger than in London. Thus, in the case
of one maker, 1,400 organisms per c.c. were found in the soda water, and a bottle of "tonic water"
contained 4,900 microbes per c.c. Another maker's soda water contained 16,400 microbes per c.c.
The soda water of a third manufacturer contained 4,100 organisms per c.c.; this maker stated that
he used the municipal supply exclusively, but on examination the water was found to contain
" various crustacea and mosquito larvae, whose presence threw some doubt on the accuracy of his
statement." The original water used by a fourth manufacturer yielded 60,600 micro-organisms per c.c.;
* E. Pfuhl has recently stated (Zeitschrift fiir Hygiene und Infectionskrank/ieiten, 1902) that he finds living typhoid
bacilli in seltzer water after at least 27 days exposure.