APPENDIX II.
LABORATORY NOTES.
By Civil Assistant Surgeon T. Sitapati Ayyar, L.M. & S.
NOTE I.—WASSERMANN TEST.
During the year 534 bloods were examined by the Wassermann test with 63 per cent.
of positive results. Of these 370 were examined as in the previous year by the Original and
Levaditi's methods. The remaining 164 bloods were subjected to a new method along with the
usual methods to find out if any advantage were to be gained thereby.
It has been found that neither the Original nor Levaditi's method were capable of taking
in all syphilitic cases. Some bloods (a small percentage of cases) gave a positive reaction with
the Original and a negative with Levaditi's method. It happened during the present year
that the reagent; alcoholic extract of ox livers, used in the Levaditi's modification proved to
be more active than the aqueous extract of syphilitic liver in the Original. Therefore another
smaller percentage of cases were missed by the Original method while the Levaditi's answered
satisfactorily.
A positive reaction obtained by either method was reported as syphilis, and thus many
clinically suggestive cases were not missed. But the examination of a blood by both tests, as
a routine, involved much labour and time ; so the idea suggested itself to mix the two reagents,
aqueous syphilitic liver extract and alcoholic ox liver extract, and subject the blood to the
mixed reagent. This method was tried simultaneously with the other two methods with
highly satisfactory results. The new method not only included all the positive cases of both
the methods separately but also gave a positive reaction in a few cases in which no positive
result could be obtained by either of the other two methods. The technique adopted is the
same as the one adopted in this laboratory for each of the two methods singly, a description
of which appeared in the Annual Report for the year 1912, except that the aqueous solution
of the alcoholic extract was made first and then the necessary quantity of acqueous syphilitic
liver extract alone added to it without the addition of another quantity of saline solution.
There is thus only one fixed quantity of saline solution and a definite quantity of each of the
alcoholic and aqueous extracts. The quantity of complement to be added should be estimated
by previous experiments to find out its minimum hæmolytic dose and the quantity inherently
absorbed by the extracts. A mixture of the ox liver extract and syphilitic liver extract forms
a powerful reagent which when. mixed with a syphilitic serum fixes a large number of the
minimum hæmolytic doses of complement.
This modified Method throws some light on the theory of the Wassermann test, and it
may be stated :—
(1) That the Wassermann test is a very complicated biological test in which many
substances enter whether purely chemical or biological.
(2) The term " antigen" is used to denote the extracts which seem to consist of several
substances and group themselves into two classes, A and B, both of which are essential for the
reaction. These are present in different proportions in different reagents. The original
syphilitic liver extract contains more of class A than of class B, and when it alone is used in
the test, only a small quantity of A sufficient to react with B is used up, the remainder of A
remaining unused. The ox liver extract contains more of B than A so that, when that reagent
alone is used, a quantity of B is left over unused. Now in a mixture of the two reagents
ox liver extract and original syphilitic liver extract, the two classes A and B will be more,
or less equal and. the united body is present in large. proportion for use. According to some
the two bodies are Lecithin and Cholesterin, or substances akin to them. This compound
body when. mixed with syphilitic serum gives rise to a sufficient quantity of the complement
fixing system.