Semi-weekly south Kentuckian. [volume] (Hopkinsville, Ky.) 1883-1889, 1888-10-23
TESTING DRINKING WATER.
Unsatisfactory Results Which Arc eome-
times Obtained-Rcmarkablo Tests.

times Obtained-Rcmarkablc Tests.
We are giving more and moro attention
to tho purity of drinking water as 1t be-
comes moro apparent that infection of Ill
most every kind travels by water. 1t be-
comes Of the highest Importance to know
whether tho tests usually resorted to for
tho detection of organic impurities are
trustworthy. II dangerous impurities
slip past these tests, they afford no pro-
lection against tho transmission of dis
ease germs. Tho Sanitarian prints pa
per by DR.. ]. A. Tanner, of Boston, giving
results Of some of his experiments in this
direction, which may almost bo called
startling.
DR.. Tanner declares boldly that tho
chemical processes relied upon for testing
wster arc las apt to condemn good
water as they are to commend 1t, and to
commend an impure water when they
should condemn it." and his statements
go far to support his theory. For example,
If per cent. of milk or any beef extract
be added to gallon of distilled water tho
processes will condemn 1t us impure be-
cause 1t contains organic matter Add q
fow million of disease germs to q gallon
of distilled water and none of tho pro-
cesses will discover them, because tho
quantity Of organic matter Is not largo
enough. Yet the one mixture Is entirely
harmless. and the other, If we accept the
germ theory, is dangerous. The combus-
tion process relies upon the proportions
found of carbon and nitrogen; tho am
monia process upon tho presence of FREQ
ammonia and albumoid ammonia; the
pcrmanganate process upon the amount
Of oxygen required to oxidizc the organic
matter. All of these tests are extremely
delicate, and slight inaccuracy is enough
to cause an impure water to be rated as
pure, or the opposite.
Tho fact that they disagree wildly In
their results with tho same water is
enough to shake faith in all of them. DR..
Tanner shows this by reference to tho in
vestigation conducted by Professor ].
Mallet for tho national board of health
some years ago, with which he was con-
nected. Nineteen samples Of natural
water, believed from actual uso to DO
wholesome, were examined by these pro
ccsses. They agreed that ten were pot
able and three were not, but us to six, or
ono-third of the number, they disagreed
totally. Then nineteen samples were
taken Of natural waters which there
seemed to be fair grounds for believing
have actually caused disease" But only
four of these were rejected Us unwhole-
some; as to nine, or one half, there was
no agreement, and six, or one-third, were
pronounced wholesome by all the pro-
ccsses. Then twenty samples were taken
of natural water Of doubtful but sus-
pected character, and as 10 these the ro-
suits wcre really more unfavorablo than
as to tho waters known to bc dangerous.
Tho most remarkable of all tho tests
were with twenty samples of good water,
to which were added various pollitlons,
such as sewage from various sources,
black yomit and like offensive and poison
ous substances. Only eight Of these
samples, less than half, were condemned
by oil tho processes; as to nino tho re-
ports did not agree. and three tho pro-
ccsses actually concurred In pronouncing
good. Water, to which enough Of weak
mixed sewage from largo public sewer
had been added to create. 1t was believed.
serious danger of typhoid, was pro
nounced to be of great organic purity" by
two processes. and good" by tho third.
A larger admixture of the samo sewage,
as much us 8 per cent. was pronounced Of
medium" quality by two processes, and
"bad" by only ono. Even more striking
examples could bo given. Yet the same
processes condemned us impure tho Lake
Drummond water from tho Dismal
swamp, which is In part the water sup
ply of Portsmouth, Va. and tho Cochitu-
alto of Boston, simply because Of the
presence of vegetable matter contributed
by leaves, roots, etc,-New York Tribune.