Evening star. [volume] (Washington, D.C.) 1854-1972, 1916-07-16

by putting some of his choice strain
of bacillus typhosuS, in which he takes
as much pride as the horticulturist does
in a rare chrysanthemum, upon COW
cred glass plate. he puts it in a safe
place al fixed temperature to let them
develop.
Now, if a colony of this aristocratic
strain lives up to expectations, it will
increase and multiply so rapidly that
to complete their number one should
use table of logarithm: they must be
true to their heredity and be virulent
typhoid organisms and they must not
be. or be contaminated with, anything
else. Any one who sees the tests that
are invariably made is sure that that
is what they are and nothing else.
One of the well known laboratory re-
actions used in the diagnosis. of typhoid
fever is the Vidal test. To- a drop of
serum is added drop of emulsion con-
tanning typhoid bacilli. and if the pa
tient has the disease the bacilli will
indicate it by a dumping or agglutina-
ton which can be readily seen in the
test tube or under the microscope. A
sample of a million or SO of the
coloniSts are introduced into a test
tube containing such serum and the
content examined for the agglutina-
ton.
It almost always "clumps" but it has
been known to fail. In such case every
member of the colony is put to death-the
whole population-without mercy. Other
tests giving color reactions are made and
every colony not running true to the soft
red which it should give is not At for
stock and is destroyed The object of
this double check is to insure that these
colonies are composed of pure strain of
virulent typhoid organisms, and this
means much more than the making of
h tcy1- do -Ioxr
If it be positively wrong it may cost the
lives of those into whom it is injected;
If 1t is merely non-effective it may fail to
save the soldier who receives it from
come from bullet a shell.
From those cultures which prove to be
all right agar slants (agar is tough
gelatin) are inoculated, and, after waiting
for day for proper growth, are emulsi-
fled in little broth and form the stock
or supply, from which to draw for the
next step If they show no contamination
after eighteen hours the growth is washed
off in small quantity of salt solution
into flask and a sample taken for a
count of the organisms.
The flask is placed in a water bath
kept by thermostat at temperature
of SO degrees centigrade for an hour,
and at the end of that time all the
organisms are dead. The count is de-
quantity of blood known to contain
about 500 red corpuscles with an equal
quantity of the emulsion, mixing and
making the count under a microscope.
By the relative number of organisms in
these counts. the amount of salt solu-
ton required to bring the dead organ
isms down to one billion to a cubic
centimeter is easily calculated. After
being properly tested, 1t is placed in
glass ampuls of suitable size and
sealed.
The tests are made by injecting small
graduated doses into three animals, a
a guinea pig and a rabbit. These
tests. which are absolute.-are made to
insure that the mixture now phophy-
laxis and ready for use, is sterile, con-
tanning no spores or matter which is
injurious to a person receiving the
charge. The ampuls are glass bottles
with long. slender necks and made in
various sizes. When filled the neck is
melted in flame and sealed. They are