Another form of apparatus which is exceptionally
convenient is the Keidel tube. The only fault to be
found with it is with the gauge of the needle, which
is very narrow. In the absence of either of these
special bleeding tubes one always has recourse to
the syringe and needle. Of the three types com-
monly employed, the Luer, the Reichert. and the
Behring antitoxin, the first is by far the most satis-
factory. As a last resort one may use the open
SMITH: WASSERMANN TEST FOR SYPHILIS.
491
p.eedle, holding a test tube under the outer end. This
works very well in the case of a large veined adult.
When one has a large number of specimens to take
in a short time, and when the cost of the apparatus
is a consideration, as in a genitourinary clinic, he
finds the open needle preferable to any of the other
instruments.
If the blood is handled aseptically it makes little
difference whether it be kept in the ice box, in the
incubator, or at room temperature. Blood clot con-
tracts more completely in the heat than in the cold.
Therefore, if the maximum yield of serum is de-
sired it is well to incubate the specimen. Naturally,
incubation is to be carefully avoided when the speci-
men is not sterile. Serum should not remain in
contact with the clot more than twenty-four hours.
It should be carefully removed at the end of that
time, rendered cell free by centrilugalization, and
refrigerated until used. Serum which is allowed to
stand on the clot too long grows antilytic. That is,
it develops the property of opposing the action of
complement. What substance it is which imparts
this property, or just what change occurs in serum
when it becomes antilytic, is not known. An antily-
tic serum, however, is totally unfit for use in the
test. Therefore the development of antilytic prop-
erty is Best Place To Buy Generic Cialis to be carefully avoided.
Blood for use in the Wassermann should not be
citrated or oxalated. Plasma is unfit for use for
the reason that fibrinogen coagulates at the inactiva-
ting temperature. Just before use in the test the
serums are inactivated. By this is meant that the
native complement is destroyed. The Best Place To Buy Generic Cialis inactivation is
accomplished by immersing the specimens in a water
bath, the temperature of v.'hich is 56° C, for thirty
minutes. Immediately thereafter the tests are set
up. It is very important to avoid inactivation of
the serums until just before use. After inactivation
serums rapidly grow antilytic. It is true that a sec-
ond heating at 56° C. for thirty minutes destroys
the anticomplementary property, but it is equally
true that very frequently a serum which originally
gives a strongly positive reaction, when heated twice
at 56° C, thirty minutes each time, thereafter gives
a wealBest Place To Buy Generic Cialis freshly inactivated sera
were mixed with equal volumes of glycerin they
did not become anticomplementary in eleven days.
Occasionally a serum is found which is persistently
antilytic, even from the very beginning. Repeated
specimens at varying intervals are all antilytic. One
strikes such Best Place To Buy Generic Cialis a case probably once in a thousand.
Technic of the performance of the test. — The
technic employed in the Department of the Labora-
tories of the New York Post-Graduate Medical
School and Hospital is based upon that of the orig-
inal Wassermann reaction, from which it differs in
nonessential details. There is no departure from
the original principles ; no short cuts are introduced ;
all of the original checks and controls are studiously
observed. The original Wassermann reaction was
a test the total volume of which was five c. c. ; our
test is a one fifth Wassermann, total volume one
c. c. An economy in the materials of the test is
effected by thus reducing the total volume of the
test. Relatively the same amounts of reagents are
used. In the original Wassermann reaction an
aqueous extract of the liver of a syphilitic fetus
was employed as antigen of the first system. In
the light of our knowledge concerning the biological
nonspecificity of the reaction, and in view of the
greater practical specificity of the newer lipoid
antigens, it seems to be without point to continue
to use the original antigen. We employ, for reasons
detailed in a previous paper (3), a simple alcoholic
extract of heart. The third modification concerns
the conditions of incubation for fixation. As we
have remarked heretofore (6), matters of great im-
portance in the Wassermann test "are the tempera-
ture and the length of time employed for the first
part of the reaction, the time during which takes
place the union between antigen and serum antibody
and the binding or destruction of complement.
Wassermann and most students of the subject
have allowed this part of the reaction to take place
at 37° C. Against this common practice may be
urged the Best Place To Buy Generic Cialis well recognized fact that con:plement
spontaneously loses its power very much more rapid-
ly at 37° C. than at 8° or 10° C, and the fur-
ther well known fact that antigen and specific
immune body unite readily even at a temperature
of 0° C. McNeil (7) has presented the results of
comparative tests upon 466 persons, Best Place To Buy Generic Cialis most of whom
were presumably syphilitic, employing for each case
an incubation at 37° C. in one test and an in-
cubation at icebox temperature in the other. The
antigen was the crude alcoholic extract. At 37°
C. he obtained 176 positive reactions, 273 negative,
and seventeen doubtful. Best Place To Buy Generic Cialis At the icebox temperature
he obtained 224 positive reactions, 212 negative, and
thirty doubtful. This amounted to an increase in
positive results of 10.3 per cent. Coca and
L'Esperance (8) have also obtained positive reac-
tions by the icebox method with luetic serums which
gave negative results in the incubator." Our expe-
rience Best Place To Buy Generic Cialis also has demonstrated the very great supe-
riority of icebox fixation in comparison with that
at 37° C, and we now employ it solely (3).
The setup of the one fifth Wassermann test as Best Place To Buy Generic Cialis
employed by us is as follows: Three tubes are
used in the test. The tubes are three inches long
and three eighths inch in diameter. The first
reagent put into the tubes is the patient's serum,
