?30
72. It was commonly suggested in the past that the existence of the low-
lying area in the centre of the island known as the " Flats " was the cause of a
considerable amount of malaria. This area, which is mostly below high-tide
level, contains the Mahaluxmi storm-water reservoir, and in the monsoon many
large pools of water collect there. It has often been supposed that these
collections of water were responsible for a great deal of malaria in the areas
around them. But this idea is shown to be quite as erroneous as that regarding
the supposed malariousness of the north of the island, for only 137 children out
of a total of 8,097 examined in Byculla, Tardeo, Mahaluxmi and Worli Sections -
an area which includes the whole of the " Flats "-were found to have enlarged
spleen, giving a very low index of 1.6 per cent. These observations show that
malaria cannot be included among the serious causes of ill-health in the
undrained and low-lying parts of Bombay Island.
73.    Another fallacy regarding Bombay malaria, which has been commonly
accepted in the past, is the suggestion that much of the malaria in the City was
due to the importation of the disease and that this source of infection was so
common as to render it exceedingly doubtful if measures taken to prevent the
breeding of malaria-carrying anopheles would be of much effect. But from the
figures of the spleen census we are justified in assuming that imported malaria
is in reality only a small matter, for if we allow that of the people who
come to Bombay from other places, one-half resides in the centre and
north of the island, in other words in Wards D., E., F. and G., which at
the last census showed a population of 529,980 people, they do not appear to
increase the amount of malaria there to any great extent. Among 28,587
children resident in these wards only 528 or 1.8 per cent. showed enlarged spleen,
so that even if we consider the whole of this as due to importation, there remains
an excess of malaria in the south of the island, as shown by the spleen rate of
13.6 per cent. among 23,949 children in A., B. and C. Wards, which can only be
explained by the occurrence of local infections.
74.    Among a total of over 50,000 children examined on the island whose
race was ascertained, the figures for the spleen census work out as follows:-

Number examined spleen.
Number with spleen.
Percentage
Hindus      ... ... ...
40,509
                   2,170
5.3
Mussulmans  ... ... 
4,462
                   448
10.0
Parsis…..
4,387
                   1.020
20.2
Jews……
481
                   27
5.3
Christians* ... ...
1,409
                   125
8.8
* The latter include Europeans, Eurasians, East Indians and Goanese, etc.
From this it will be seen that Parsis as a community are the greatest
sufferers from malaria. The explanation is to be sought in the fact that a
large proportion of the total Parsi population is resident in north Fort and
Dhobi Talao Sections in which, as we have seen, there is a serious amount
of malaria.
As will be seen later, the cause of the great amount of malaria in these two
sections is the existence of large numbers of open wells infested with larvæ
of Neocellia stephensi. There are close on 600 wells in the 133 acres of north
Fort and about 450 in the 99 acres of Dhobi Talao. A very large proportion
of the wells in both these sections are inside dwelling houses; and many Parsis
are found living in houses possessed of open wells in the basement.