10
REPORT OF THE KING INSTITUTE GUINDY
The results show :—
(i) Of negative Kahns as much as 95.7 per cent were also Wassermann
negative.
(ii) A weak positive Kahn was usually Wassermann negative. Here, I
must say that this was partly due to the fact that, in the interpretation of
these Kahn tests positive weak findings included results in which a weak
precipitate was given in only one tube. Since this is now usually classed as
Kahn negative, we can discount the results for this particular finding. This
does not apply to any other of these findings, for the usual method of
grading precipitates (here into 3 grades) and taking the average for the three
tubes was adopted for the other readings of the Kahn test.
(iii) As regards moderate positive Kahns (average of + + ) 26.5 per cent
were either moderate or strong Wassermann positive. But of strong positive
Kahns (average of + +) 61.8 per cent were either moderate or strong
Wassermann positive.
Thus so far as these results go, while there is a very good agreement
between the two tests when the Kahn test is negative, there is only a moderate
agreement when the Kahn test is strong positive, and a poor agreement when it
is moderate positive.
So, though I am aware that certain laboratories have adopted the easier
Kahn test as a routine instead of the Wassermann, I disagree with the con
-clusion that the Kahn test is as accurate as the Wassermann. It may be
more accurate or less accurate than the Wassermann so far as correspondence
with clinical results go and this is the essential comparison needed, but here
it has shown itself to be certainly not equally accurate because of the distinct
discrepancy mentioned.
Accordingly, since we could not definitely substitute the Wassermann for
the Kahn test, but yet wished to reduce the number of Wassermanns, it was
arranged through the Surgeon-General that all ordinary bloods and sera now
submitted for the Wassermann reaction from Government Institutions in future
should be no longer labelled “ For Wassermann ” but simply “ For S.R.”—for a
Serum Reaction. For what we propose to do is to do a Kahn test on all, then, on
only those positive to Kahn, to do a Wassermann test. This would reduce our
work a great deal without any diminution of accuracy. Special cases, of course,
would have whatever test is required. This plan has recently been put into
operation and works well.
(D) PUBLIC HEALTH SECTIONS.
Bacteriological and Chemical.
(1)
Charge of work.— Mr. Herbert Hawley, the Public Analyst continued
to be in charge of the Public Health Sections during the year and has collabo-
rated in writing this report.
Mr. T. N. S. Raghavachari continued to act as Senior Bacteriological
Assistant and Mr. K.V. Sundaram Ayyar as Senior Chemical Assistant throughout
the year.
(2)
Protected water-supplies.— Table XIII gives the total number of
examinations carried out, and it will be seen that there has been a still further
increase in the number of examinations—1,242 samples as against 1,048 last year.
A synopsis of the results of periodical examinations is given in table XIV. The
following call for special comment :—
( a) Municipal supplies :—
Ad ō ni .—The supply continued to be very unsatisfactory in spite of
repeated adverse comments and suggestions for improvement.
Cocanada .—The results of the slow sand filtration were variable.
Coonoor. —The supply derived from Bandami Reservoir does not reach the
standard to be expected of a Hill Station impounded water.