The morning call., 1891-10-18

smell almost putrid. In fact, it is a mass of
decaying organic matter. Examined on the
stage of a microscope it will be seen to con-
sist OF tattered fragments of vegetable
cellular tissue and of dead water crustaceans
and infusora of minute size. and. perhaps,
there may be seen here and there an in
fnitesimal worm besides.
1t is essential to have reservoirs, tanks
and other bodies OF water that contain much
organic matter quite exposed to the light
and air. The light is needed by the plants
in the conversion of the mineral substances
VIII ich they absorb from the water into the
various constituents which go TO make up
the oils, fats, starch grains and other con-
tents of the veget bile cells, and the air Is
needed to keep the water pure and we'll sup
piled with oxygen.
All large bodies Of water used for domes-
tic purposes, such as supplying the houses
in large cities, should have rapid dow.
and If possible, 90 dashing down one or
more precipitous descents; or in case they
cannot flow so rapidly as it is possible to
fill them. the overflow pipe or pipes should
be al the bottom, or One-third of the way up
of the reservoir, and not near the top.
Where the water is standing In large pond
having no overflow water plants of cOnSid-
cradle size and rapid growth should be
placed in the water 50 as to keep it thor
oughly aerated, and, therefore. reasonably
pure, by the oxygen heing almost constantly
given off in small globules By their leaves.
These globules of oxygen may be seen adj
herring to the surface OF the leaves of most
any water weeds on warm summer day.
Schuclboys and anglers call them air Duo-
bles."
Many persons imagine that water con-
tanning any living organisms, whether of
animal or vegetable nature, especially II
sucn organisms are of low development in
ba al If n which they
pear chiefly as sediment or scum, must be
impure and unwholesome. Such IS not the
case. however.
The growth of odorless plants in the Gro
ton water will never render 1t impure, but.
rather they will tend to clear IL OF the for
eign substances that are blown or poured
into it. and will absorb the carbonic acid
gas resulting from the decomposition of
animal bodies that may have fallen into the
lake.
The majority of the water plants passing
through the city water pipes are very small
vegetable bodies known as desmids and
diatnms The almost infinite variety Of
forms and shapes assumed by these plants,
small as they are, is something to wonder at
Diatoms, which are, like the desmids,
group of alge very low in the scale OF de-
velopment, are quite numerous in the
Croton water. and, so far as individual
plants are concerned, come i'll greater
abundance through the city water pipes
than any other plants. They are OF more
interest to the average microscopic, per-
haps. than the desmids, on account of the
great variety and beauty OF the sculptured
markings on their cell walls. These mark
ings are not always distinctly Visible, until
the plants have been boiled in sulphuric
acid to eat off part of the silica. which al
most invariably covers their surface.
They grow singly or in groups, and
present some variety in their modes
of groupings, although in form they
do not vary so much, perhaps, as do the
desmids. When not growing sin2ly or
on stems or in loose families in an amor
phouS mass of jelly, they grow side by side.
In growing side by side they may develop in
straight lines Figure y, or form exact circles,
as shown in figure in the illustrations, or
they may radiate, as in figure 9. Figure 10
shows three diatOms imbedded in geati-
nous matrix. In figure II is seen Melosira
crotoneBsis, Bailey. the individuals OF which
adhere side by side, similarly as in figure T.
1t is one of the most frequent forms in
Croton water and attains considerable
length for plants of such small size. Figure
u shows a diatom similar to figure Z, but
whils the latter always grows in rows, the
former grows singly.
Diatoms multiply in several ways. One
is by natural division of their cells, and,
as they donOt grow after being once formed,
each frustule resulting from division is
smaller than the one coming from that be-
diat0m are smaller than the parent plant
from which they sprang. The last one
formed is, therefore, smallest OF all. In
fact, so prolific is their REPRODUCTION in this
way that a single frustule and its progeny
would give rise TO more than 30. 100000 indi-
viduals. did they all survive, and some OF
these would and do become SO minute as to
go readily through the pores OF filt"riug
paper, while still living and endowed with
the power of motion. And yet, small as
diatOms are, they perform no mean part in
the economy OF nature. Their silicious
covering renders them almost indestluet-
ible. They flourish in thermal springs, and
survive being frozen in block of ice
Even in the dark they live longer than can
most other light-loving plants, and they
have been known to live for quarter of O
century in their native element.
There are more than 5000 distinct kinds OF
diatoms known to science. They are found
at the lowest depths of the sea that have
been dredged and under the sand on the
seash0re. Vast quantities have formed
fosslifer0us deposits in various parts of the
world. In our own country, Richmond, Va,
may be cited as being built on such de-
post. which is from twenty to eighty feet
deep and several miles in extent. 1t is i'm
possible to imagine the immense number of
individual dal0ms it took To make such n
bed Man could not estimate the number
by any method of calculation, nor has he
signs or symbols for expressing such stu
penGous numbers. Yet SO active are dat
ons in reproducing their kind and so much
silica III the water do the individual diat0ms