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baker's, butcher's or grocer's shop, or a marine store dealer's or other premises likely, by forming a
subsidiary centre of attraction for flies to interfere with the observations*
The method of determining the extent of the fly nuisance in a particular house was to hang up a
fly paper from the ceiling or gas bracket of one of the rooms, to allow it to remain exposed for a definite
period of 24, 48 or 72 hours (as the case might be), and then to count the number of flies on the paper.
The papers used were smeared over with a sticky compound known as "honey-gum" and were about
12 inches by 8 inches in size. Experience acquired with regard to other papers of somewhat similar
character seemed to show that there were no great variations in the number of flies caught under the
different circumstances; but, for the sake of uniformity in all the observations, the numbers referred to in
this report were obtained by use of fly papers of one particular type. It would, no doubt, have been
advantageous, had it been possible, in place of the fly papers to have used fly traps, as has been done
by Dr. Niven of Manchester, but inasmuch as it was desired to carry out experiments on a considerable
scale the question of cost assumed large importance and indeed made it necessary to have recourse to
the cheapest method of catching flies which could be relied upon to give fairly accurate results.
The papers were in no instance placed in a dark part of a room, on the other hand they were not
exposed to direct sunlight. They were, as a rule, collected on Mondays, Wednesdays and Fridays, and
special effort was made to secure their being renewed at the same hour in the case of each particular room.
The endeavour was made, as far as this was practicable, to obtain for purposes of observation at least two
houses as near as possible to the centre of investigation, at least two houses 50 yards away, and two
houses about 100 yards away, were also, when possible fixed upon. In the case of premises with large
accumulations of refuse and manure, a few houses were chosen, where this could be done, at greater
distances; the two houses selected at each particular distance were if practicable situated at opposite
points of the compass—one of them, when possible, to the North East and the other to the South West
of the centre.
At first, considerable difficulty was experienced in gaining the co-operation of occupiers of the
houses, but, as time went on, and when the benefit resulting from ridding the rooms of numbers of flies
became appreciated, the difficulty, instead of being one of obtaining permission to use a particular
room, became rather one of obviating the necessity of making use of more rooms than were really
essential for the purpose of the experiment,—occupiers of rooms who were already exhibiting papers
being anxious that friends and relations should also be given the opportunity of doing so.
With regard to the character of the premises chosen as centres, the main idea kept in view was to
select places to, or at, which large quantities of house refuse, manure, etc., were brought, or were allowed
to accumulate. Thus depots used by borough councils, or by contractors, for the purpose of dealing
with refuse, and large stabling premises and cowsheds were naturally selected in the first instance.
For the purposes of contrast, two premises at which offensive trades were carried on, and further a
jam factory and a cattle market, were included in the list.
The following is a brief description of the twelve sets of premises chosen as centres.
(1) Borough Council Depot (No. 1).—This depot adjoins a railway siding, with lines of trucks into
which horse manure and stable refuse are loaded for removal from London. Roughly speaking
some twelve truck loads of horse manure and twenty-four of house refuse were removed daily
during the summer of 1907 from this depot. The material brought in during the day was, speaking
generally, removed the same night, and this rule, with some exceptione, was fairly well adhered to
throughout the summer. On particular occasions, however, considerable accumulations of road
slop, etc., were observed.
(2) Borough Council Depot (No. 2).—This is the depot referred to in the early part of this
report. It is situated on the banks of a canal, and covers an area of nearly two acres. Between
55 and 65 cart-loads of house refuse are brought to this depot from various parts of the borough
daily. The refuse is passed over a screen, through which heavy matter falls, while the lighter
particles are picked up and burnt in the furnace. The refuse which has passed through is lifted by
an elevator into a revolving screen divided into three sections. The soft core derived from this
screen is carted away to a "tip" on the outskirts of the county; the ash and breeze are barged
away, some three barge loads being removed each week. Accumulations of ash and breeze were
frequently noted, but the soft core was fairly regularly removed. Road-slop, but no manure, is
deposited at the depot. There are some stables, but no cowhouses in the neighbourhood.
(3) Borough Council's and Contractors' Dust Wharves.—The centre chosen in this case was a
point midway between two wharves, situated on the North bank of a canal, each covering an area
of about half an acre. Refuse is brought to the one on the East from neighbouring districts and
dealt with by a contractor, who causes it to be screened by machinery and allows no accumulation
to collect. To the other wharf house refuse is brought by the borough council and dealt with in
a similar manner. From these two wharves more than 20 barge loads of house refuse are removed
* The selection of the rooms in which the number of flies was to be computed was entrusted to the
Council's Inspectors, Messsrs. Tuck, Lewis, Harrison, Perry, Swinson, Mernagh and Powell, and these officers
undertook the work of securing the co-operation of the occupiers of the premises; each officer moreover, kept the
record for one or more of the twelve areas. The special knowledge of the inspectors concerning these p trticular
centres and the surrounding localities thus became available for the purposes of the enquiry. It was hoped that the
work could be done without material interference with the inspectors' ordinary duties; it was found, however, that
no light task had been entered upon, and some strain was especially experienced when, in order to maintain contiruitv
of the observations during August and September, the duties were necessarily performed by a more limited staff,
Inspectors Lightfoot and Hitchmough rendered assistance during this period. The two photographs reproduced were
taken by Messrs. Lightfoot and Swinson, and the calculations, and the preparation of the charts were undertaken by
Messrs. Arery and O'Carroll.
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