Evening star. [volume] (Washington, D.C.) 1854-1972, 1894-02-22
DR.. Theobald Smith Talks About
Channels of Infection.
INVESTIGATIONS OF POTOMAC WATER
It is Acquitted Of Responsibility for
Typhoid Fever.
HYGIENE FOR THE HOUSE

Vltation of the Sanitary League at the
Columbian University lecture hall. His
subject was Channels of Infection, With
Special Reference to Water and MILK" and
he gave some interesting information re-
specting infectious diseases and the ways
in which they may be communicated. De-
spite the storm he had a good audience. and
at the close he was warmly congratulated.
Mr.. r. Ross Perry. president of the SAM
tary League. introduced the speaker, and in
the course Of his remarks called attention
to the fact that the annual meeting of the
league will be held next Monday night in
the same hall. and extended an invitation
to all interested in the work Of the league
to be present
After referring to the air as the means Of
conveying infection, the speaker said there
was time in the history of sanitation
when sewer air was made responsible for
many Of the ills that afflict the inhabi-
tants of cities and towns. Now that We
are amply protected by legislation against
this unwholesome guest, it may be to the
point to refer briefly to the real dangers
involved. 1t is not to be denied that the
ontinuous breathing of sewer air leads to
serious disorders of the bodily functions by
virtue of the noxious gases arising from the
processes Of decomposition. These dis
orders we must distinctly separate from
those caused by living organisms, and
which We denote infectious diseases. If We
hold fast to the fact that bacteria are not
given off from moist surfaces, excepting in
sprays due to violent commotion, we will
understand why sewer air must be freer
from floating bacteria than the dry air of
our rooms and streets. When the protective
seals in houses long unoccupied have dried
out bacteria may escape from sewer pipes,
and under such circumstances caution
should be exercised. ! venture to state,
however. that the time is past when on the
sudden appearance of some infectious dis
ease Of distinctly intestinal nature the
otherwise good plumbing is the first thing
to be torn out and overhauled. / believe
that at the present time most sanitarians
in such cases will look first after the food
supply.
Water as a Vehicle of Infection.
vehicle of infectious agents, especially
those of typhoid fever, Asiatic cholera and
the more common diarrhoeal and dysenteric
troubles, has been thoroughly set forth
by DIR. Smart, in his recent lecture before
this league that need not spend any time
in bringing it before you now. l therefore
pass over the various calamities of recent
years which might be cited as Illustrations
of the dangers of polluted water supplies
and limit my remarks to a few facts con-
corning bacteria in water. 1t is a note
worthy fact that the water which percolates
through the porous strata of the solid and
collects as ground water has been deprived
of bacteria in its downward progress by the
hltering power of the earth. When wells are
dug the ground water which collects in
them receives bacteria either from the sur
face or from the uppermost layers of the
SOIL and the sanitary quality of any given
well water will depend on the care with
which surface contamination is excluded in
the construction of the well. With surface
water such as that of streams, rivers and
lakes, the conditions are somewhat differ
ent. The purest surface water of the will
derneSs contains a certain number of bac-
derived of he
and from animal and vegetable organisms
undergoing decomposition. For the same
stream there is a remarkable uniformity in
the number of bacteria, ii We except periods
of rains, and this number is, as a rule, pro-
portional to the amount of sewage a stream
receives. The enormous increase of bac-
terra in rivers into which cities drain their
refuse has been amply illustrated in recent
years. Some Investigations of the effect of
the sewage of Vienna on the Danube are
worthy of mention in this connection. On
reaching Vienna the water of the Danube
contains about 1900 bacteria in cubic
centimeter. Qt would take two cubic cent?
meters, the speaker explained, to fill a small
thimble). Below Vienna the river receives
from the sewage an addition of over 700
bacteria in a cubic centimeter and even six
teen miles below the city the river still con-
tains 400 germs per cubic centimeter more
than above Vienna. Since very little sew
age is said to enter the river below Vienna,
these bacteria are nearly all to be credited
to the pollution sixteen miles above. This
enormous difference in the water above and
below the city was scarcely indicated by
the chemical tests.
washinxtOn's Water Supply.
1T will be at once appreciated that a
stream receiving the sewage Of a large city
will always receive a number of disease
germs. and if the water is taken from such
a stream the typhoid mortality will always
be high and occasionally blossom out in
epidemic form. The relative purity of our
own supply has been a subject of comment
for many years. Unfortunately, there are
no data on record which give any in
formation of the bacteriology of the water
1t enters the conduit My own observa-
tons were made on tap water in the city,
and as there is always more or less de-
struction of bacteria going on in the reser-
voir and conduts, figures obtained from the
examination of tap water are not to be
compared with those obtained from sam
pies taken directly from the stream. Just
at present it would be very desirable to
know the difference in the number of bac-
terra entering the conduit and those which
appear in our houses. For after the COM
pleton of the improvements now under way
we shall wish to know what difference they
are making in our water supply ana what
beneficial effect is being exercised by the
new reservoir in eliminating undesirable
bacteria.
About eight years ago 1 became very
much interested in watching the great and
sudden fluctuations in the turbidity of Po-
tomac water, especially during the winter
season, after heavy rains and winds. A
series of meteorological tests showed that
with the appearance of this turbidity there
came a host of bacteria. Their numbers
fiuctuated with the degree of turbidity, the
most turbid water in 1SS6 containing nearly
10000 bacteria in cubic centimeter the
clearest about $50. Since then 1 have at
rare intervals found that this parallel fluc-
tuation in bacteria and turbidity has re-
NAMED the same.
Not Responsible for Typhoid.
Here is condition which would lead one
to look for most intestif al disc ase during or
soon after the period of greatest turbidity
namely, the colder months of the year An
examination of the statistics compiled by
the health office showed on the contrary
the highest mortality from typhoid fever in
the summer months, when the bacteria I'm
the water are fewer in number. The Po-
tomac. therefore, cannot be accused of
causing our high typhoid mortality until
other possible agencies to which l shall al
Jude further on. have been excluded. Nor
can 1t be urged that the low number of