REPORT ON THE WORK CARRIED OUT IN THE MICRO-BIOLOGICAL.
SECTION OF THE KING INSTITUTE OF PREVENTIVE MEDICINE,.
GUINDY,FOR THE YEAR 1913.
Dr. F. M. Gibson continued in charge of the Institute from the beginning of the
year till August 20th, when he proceeded on leave. Captain W. S. Patton, I.M.S.,
held charge from that date till September 4th ; and from September 5th till the end
of the year Major J. W. Cornwall, I.M.S., was in charge.
From January 1st till July 14th Captain F. W. Cragg, I.M.S., acted as Assistant
Director during the employment of Captain W. S. Patton, I.M.S., on special duty in
connection with Kala-Azar. Captain Patton resumed his substantive appointment of
Assistant Director on July 15th and held it till the end of the year.
Water analysis.—The routine quarterly analysis of samples from the water
- s u p p l i e s o f m u n i c i p a l i t i e s a n d j a i l s w a s d i s c o n t i n u e d u n d e r t h e o r d e r s o f G o v e r n m e n t ,
in order that the analysis of samples from the four experimental filters, which had
been erected in the grounds of the institute by the Sanitary Engineer's Department,
might be attended to. Two sand filters, the Madras Standard and the Clemesha
patterns, having different thicknesses of sand and different filter heads, and two gravity
mechanical filters, the Jewell and the Paterson, formed the subjects of the experiments.
The objects of the experiment were to find—
(1) which of the two, the sand or the mechanical filter, was the more efficient.
under varying conditions,
(2) which of the two sand filters was the more efficient, and
(3) which of the two mechanical filters was the more efficient.
Various subsidiary points arise such as—
(1) the right quantity of coagulant to use for the mechanical filters under
varying conditions of the same water and with waters of very different chemical
composition,
(2) how long the filtrate of the mechanical filters ought to be run to waste,
(3) what thickness of sand gives the best results,
(4) what is the minimum thickness of sand. that can be used with reasonable
. efficiency, and
(5) what is the maximum filter head that can be employed with safety on a
sand filter.
Precisely the same routine of bacteriological examination and chemical analysis
was followed in dealing with the samples from the experimental filters as has been
customary here for several years past. The work consequently has been very heavy
and a vast amount of detailed information has been collected.
No formal report of the results has yet been made out as the analyses are still
being carried on at the desire of the Sanitary Engineer, but an interim survey of the-
situation has been submitted through the usual channels.
The analysis of stray samples of water sent by various authorities was continued.
Sometimes it happens that samples are sent the analysis of which when completed
can afford no useful information to any one ; for instance, ( a )
sample from a stag
- n a n t p o o l i n t h e b e d o f a r i v e r , u n f i t f o r d r i n k i n g a n d n o t u s e d ;(
b )
s a m p l e f r o m
the Cooum. It was known by the senders that these places were, not generally used
for drinking ; it was equally well known that they were unfit to drink. The-
condemnation of this Institute is superfluous.