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The Pamphlet Collection of Sir Robert Stout: Volume 12

Sanitary Report

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Sanitary Report.

Chapter I.

Duties of a Medical Officer of Health.

1To ascertain what local causes prejudicially affect the public health in the district; to inform the Board of these discovered causes; and to suggest such means for their removal as medical science can advise.
2To seek information of the occurrence of cases of epidemic, endemic, or contagious diseases, and, when informed, to visit the localities, ascertain the extent of the malady, the local causes likely to conduce to the diffusion thereof, and give such warning as may induce persons infected to have recourse to medical treatment. In case of an out-break of small-pox, to inquire into the history thereof, and as to the practice of vaccination in the neighbourhood.
3To inspect any meat exposed for sale for human food, whenever required to do so by an officer of the Board or any police officer; and to give his opinion as to the fitness or otherwise of such meat being used as human food, whenever required by a Justice of Peace.
4Upon any complaint received by him of the emission of any noxious or offensive smell from any process of trade carried on in any manufactory, yard, house, or premises, or of atmospheric pollution from any drains or sewers, to inquire into the causes, and report upon the means for the prevention thereof.
5To perform any duties imposed by an Act of Parliament on the Officer of Health.
6-7To attend the meetings of the Board when necessary. To report quarterly the nature and amount of sickness and death, the number of births and of persons vaccinated; and to present annually a report and tabular return of the ascertained sickness and mortality of the district.
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Chapter II.

Topography, &c.

The City of Dunedin stands upon an area of 900 acres. Upon the West is the Town Belt, having an area of 500 acres, and upon the East 100 acres, are about to be reclaimed from the Harbour.

Two-thirds of the City stand upon hilly ground,* which irregularly slopes towards the bay.

The greatest altitude is 306.60 feet above high water mark; this is obtained in High Ward in Duncan Street. The lowest level is .40 below high water mark, situated at the foot of Hanover Street.

The Octagon level at its highest point is 50.15 feet above high water mark; the reclamation level being 6.10

The substratum of the City consists of basaltic rock and alluvial clay.

* Miram's Report on Drainage and Sewerage, submitted to the City Council of Dunedin, 1872.

Miram's Map of Dunedin.

Chapter III.

Inhabitants, &c.

Our inhabitants, including Chinese and Half-Castes, numbered in March, 1874, 18,499-the male population contributing 9529, the female, 8970. At present, the number of children contributing to this number I have been unable to ascertain. Should the information be procurable, it will be added as a foot-note.

The inhabited tenements numbered 3444-there being in addition 118 either uninhabited or in process of building. Of inhabited houses, by far the greater number were found to be wood and iron; of such there were 3138. Of houses built of brick and stone there were 293. The composition of the remaining houses was either of miscellaneous material or not stated.

Houses possessing but two rooms numbered 638; houses possessing from three to four, 1491; houses possessing from five to six numbered 676; houses possessing more than six numbered 513. Of the 29 remaining houses, the number of rooms in each is not stated.§

Immigrants to the number of 8323 have landed at Port Chalmers since March. Their destination, however, is not recorded. Males, 4354; Females, 3629.

§ Census March, 1874.

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Chapter IV.

Public Buildings, &c.

Until an Inspector is placed at my disposal, I shall be unable to give a report as to the sanitary condition of our Churches, Schools, Hotels, Public Halls, Manufactories, Theatres, &c. I have, however, visited the Hospital; and through the courtesy of Dr. Yates, I am able to furnish the following particulars concerning it:—

This Hospital is capable of holding 180 beds. It has two flats, there being eight wards in each, capable of holding from eighteen to twenty beds. I found, at a rough estimate, the dimensions to be 50 feet long, 22 wide, and 20 high. Each ward upon the first flat has seven windows placed upon its west side, the windows having a valvular opening at their inferior extremity. This is a clumsy and dangerous arrangement, as they open just a little above and immediately behind the beds. These wards likewise possess a ventilator in the opposite wall, a grating ventilator on the floor (communicating with the exterior of the building by means of a wooden tube), and a fire-place.

In the wards situated on the second flat, there is a larger and a smaller row of windows, making thirty; only ten of which are capable of being opened.

Situated upon the ground flat there are three lying-in wards. Two of these are respectively about 25 feet long, 12 wide, and 11 high, having three windows, a ground ventilator, and fire-place. The third ward is a little smaller, having two windows, a ground ventilator, and fire-place. All these windows open at the top and bottom. Three or four beds are usually accommodated in each ward.*

In another part of the building there is an annexed ward, measuring about 75 feet long, 17 wide, but only from 11 to 12 feet high, the roof being slanting. The complement of this ward is about 24 beds. It is only possible to open three windows out of fifteen (!) which run along one side of the ward. Opposite to these windows there is a wooden wall, with four small openings (about two feet square), which may be opened or closed at will by means of sliding doors. These, when I entered the ward, were closed with one exception; the atmosphere of the place was consequently most distressing. This ward is without exception the worst ventilated in the building. Dr. Yates himself admits that the roof is altogether too low, and that there is not nearly sufficient ventilation. Nevertheless, this ward could be immensely improved with very little expense or trouble.

There being no means of registering the temperature in the Hospital, I would suggest that a thermometer be supplied to each ward.

* It is unadvisable that lying-in-wards should be anywhere near, let alone within, a general hospital.

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Chapter V.

Water Supply, &c.

Dunedin is supplied by gravitation through leaden service pipes from a reservoir capable of holding 51 million gallons. This reservoir is filled by Ross' Creek, the which creek is formed by the union of several streams which take their rise in the Flagstaff Range. The reservoir is 50 feet deep, has a catchment drain on one side, and a storm-water channel on the other in order to prevent extraneous matter from filtering into it. Any impurities which enter it come from the banks of Ross' Creek, and possibly from the gathering ground I he daily consumption per head is 50 gallons, but from this we must take the water supplied to manufactories. By and by, we will be able to do this, as metres are about to be established.

The city of Glasgow supplies 50 gallons per individual, but on the other hand London only supplies about 25 gallons and Edinburgh 35.*

I am informed by Mr. M'Gregor, C.E., that improvements are about to be made, so that soon we shall have a larger and purer supply, the present difficulty being that the land through which Ross' Creek runs cannot be manipulated, as it belongs to a party who has hitherto refused all offers to purchase. Mr. M'Gregor thinks that now the water supply is in the hands of the Corporation, this difficulty may shortly be overcome, in which case filter beds could easily be constructed. At present the water, though tolerable, is not pure, for according to Dr. Black's last analysis there were 0.95 grs. of organic matter per gallon in the lower reservoir. This is 0.16 less pure than London Water.

* Haskoll on Engineering.

Chapter VI.


It may be said that a limited natural drainage is the only one Dunedin possesses. It is true a large sewer drains Rattray Street gully into the Bay, and that another is in process of construction along St. Andrew Street and York Place; but these, of course, are wholly inadequate for the drainage of a city of 1,000 acres.

The evil results of this state of matters are, that our sewage poisons our houses, our streets are filthy, and our flat in many parts is a saturated mass of pollution.

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Your City Surveyor in 1872 submitted a plan to the Council for the drainage and sewerage of the City. His method of drainage, so far as I can judge, is admirable, though I don't agree with him in his statement that the Bay is the best outfall for sewage; but this I shall refer to when placing before you the scheme that has occurred to me regarding the disposal of our sewage.

Another, and I think, perhaps, a better plan, has been suggested to you by Mr. Burt, C.E., in which he proposes to divert the Water of Leith for the flushing of a main sewer, which he suggests will run by the Bay, being continued along the Anderson's Bay Road, having its outfall directly into the ocean.

I proposed to Mr. Burt a modification of his plan regarding the outfall into the ocean, with which he cordially agreed. What that modification is I will state in the chapter on Sewage.*

* Since writing the above, I have witnessed, under premises pulled down in Rattray Street, a great accumulation of decomposed water, which had collected there and failed to escape through there being no drainage. Animal matter was there breeding pestilence by its decay.

Chapter VII.


As stated in the last chapter, we are badly off for the disposal of our sewage. Some few closets empty themselves into Rattray Street sewer, some empty themselves into our streets, in many cases by means of private drains, at times assisted by flood waters; others are emptied at irregular intervals by nightmen, and the soil deposited at a depot in a paddock a little beyond the Gas Works.

I need not tell you that this is not at all a satisfactory state of things. Matters would not be so bad if, instead of this hap-hazard system, we had earth closets universally in use, and regularly emptied. This, in fact, is a method much in favour in some towns in England. It would, at all events, be better than our present method, and would prevent our Bay from becoming a source of danger from contamination.

To show you that the Harbour is not the proper place for the reception of sewage matters, allow me to quote what Dr. Macadam, Professor of Chemistry in Edinburgh, says regarding such matters:

"In the investigations relating to the sewage of London, and its effects on the Thames, and the injury inflicted thereby, it is conclusively shown that the greatest part of the nuisance lies in the

Haskoll on Engineering.?

page 10 sedimentary matter which lines the banks, and is in an active state of putrefaction; and the same conclusion has been come to by me in regard to the foul deposits in the bottom of the lakes, and in the bed of the Water and Harbour of Leith. The gases evolved from the decomposing matters were generally recognised in the immediate vicinity of the Water of Leith conveying the sewage, as also in close proximity to the main drains or sewers. The odour was not that of sulphuretted hydrogen, but a heavy, fœtid, nauseous odour, specially observable immediately over the stream, and was doubtless due to the escape of gases produced by the putrefaction of the organic deposits."

Dr. Letheby, Medical Officer of Health for the City of London, says, regarding the mud deposited in the Thames:—

"It is black and foetid, and in a state of active putrefactive decomposition. When examined with the microscope, it was found to consist of broken-up sewage matter, with the remains of myriads of animalcules . . . . It is evident from this, as well as from what I know of the usual composition of the warp or mud of rivers, that this is a very large proportion of organic matter, and that by undergoing putrefactive decomposition, the mud which is accumulating in such large quantities at the sewer outfalls may be a cause for serious alarm, especially as it there meets with sea water, the sulphates of which may, by their chemical decomposition by the putrefying mud, occasion the escape of much sulphuretted hydrogen, and set up that remarkably offensive change which is characteristic of the action of sewage upon sea water."

It is thus seen that some better plan is urgently called for. The question then conies to be-out of the many systems elsewhere adopted, which is the one most suited for Dunedin. After much deliberation I have come to the conclusion that what is termed the Separate or Irrigation system is the one that will yield the best results.

The scheme that has occurred to me is the following:—The sandhills at the Ocean Beach should be properly prepared and utilized as a filtering area. Only a very small portion of these sandhills would be required; for Merthyr Tydvil, a town numbering 50,000 inhabitants, has only twenty acres of prepared land for the same purpose; and, as we shall see presently, the whole scheme is a complete success.

Accompanying this report is a plan drawn by Mr. Burt, C.E., embodying my modification of his former one, by means of which the City could dispose of its sewage in the manner I advise.

In Merthyr Tydvil a system of filtration and irrigation had page 11 been earned out two years when Dr. Dyke, the Medical Health Officer for that town, wrote of it as follows:—

"The result of this plan of disposing of sewage by 'downward intermittent filtration' may be seen in this sample of effluent water, taken from the outlet of the main drain. You will observe that the water is bright, perfectly pellucid, free from smell, and only tastes of common salt. It may safely be drunk;-in fact, is used by the workmen employed on the farms. During the process of irrigation no nuisance is caused, for the soil quickly absorbs all the fluids passed into it; in fact, in two or three hours after the water has ceased to flow on the land, an observer would say that the ground had not been wetted for days. The workmen say that no unpleasant smell is noticed, nor has the health of the persons employed in any one instance been affected by any presumed poisonous exhalations. The only imperfection of the plan is that at the end of the furrows nearest the lowest corner of a plot a slight deposit of scum is found. This scum is formed by the fine insoluble precipitate caused mainly, I believe, by the addition of lime to the sewage stream.* On the ridges of this prepared soil, cabbages, brocoli, carrots, turnips, parsnips, beans, peas, lettuces, onions, &c., are grown. . . . . By passing the sewage through simple and inexpensive strainers, it is delivered on the land in such a state that no nuisance or inconvenience results."

The plan and mode of irrigation, as adopted at Merthyr, is as follows:—

There are two stone tanks, 200 feet long, 5 feet wide, and 5 feet deep, the top being covered by moveable planks. "Along the floor of each tank an 18-inch square drain of open work is formed. The tank is divided into three compartments of open brick-work. Between the sides of the drain, and between the walls of the tank, and over the drain to a depth of twelve inches of the whole width and length of the tank, the spaces are filled with broken furnace cinders. The sewage, charged with lime, passes into the tank and percolates through the broken cinders, passes through the perforations in the walls of the under-drain, and then flows onward, the conduits conveying it to the land. Upon the surface of the cinders, all the gross or solid portions of the sewage are left. Each tank works four or five days, in that period arresting in transit about two tons a day of sewage slush and refuse. This is taken off the surface, wheeled in barrows into a field close at hand, and mixed with fresh coal ashes (about three tons) brought daily from the neighbouring village by the public scavenger. About

* He advises, consequently, that no lime should in future be used.

The area of Merthyr Tydvil is 18,000 acres; 3,000 occupied by houses and gardens, having a population of 50,000, living in 10,000 different tenements.

page 12 twenty acres of land immediately adjoining the road upon which the tanks are placed have been arranged into filtering beds. The land is a loamy soil, 18 inches thick, overlying a bed of gravel. The whole of these 20 acres has been under-drained to a depth of from 5 to 7 feet. The lateral drains are placed at regular distances from each other, and run towards the main or effluent drain-this is everywhere 6 ft. deep. The surface of the land is formed into beds; these have been made to slope towards the main drain by a fall of 1 to 150. The surface is ploughed into ridges; on these, vegetables are planted, or seeds sown; the line of the ridge furrowed is in the direction of the under drain. Along the raised margin of each bed, in each area, delivering carriers are placed, one edge being slightly depressed. The strained sewage passes from the conduits into the delivering carriers, and as it overflows the depressed edges, runs gently into and along the furrows down to the lowest and most distant part of the plot. The sewage continues to be delivered for 6 hours; then an interval of 18 hours takes place, and again the land is thoroughly charged with the fertilising stream. The water percolates through the 6 feet of earth and reaches the lateral drains, which convey it to the main effluent drain. Adjoining the filtration areas there are 235 acres laid out to be used as irrigation lands."

The River Pollution Commissioners, according to Dr. Dyke, report as follows:—

"The experience of these filter beds at Merthyr Tydvil has made plain what the experiments in our laboratory had previously established. Towns can cleanse their sewage within a much smaller quantity of land than any experience hitherto had might lead them to expect. Sewage irrigation offers the great advantage of a remunerative return.* Intermittent filtration may also now be confidently accepted as a sufficient remedy for the sewage nuisance. These two methods are essentially one, wherever thorough drainage accompanies-as it always should-the extensive form of irrigation, and they are the only methods which are perfectly trustworthy for the abatement of this sewage nuisance."

Dr. Edward Franklin says:—"Of the effluent water from these filtering areas, the result is highly satisfactory. Indeed on the 10th June, 1871, the water entry, the Taff, from the Merthyr filter, was considerably purer than the Thames water which we are often compelled to drink in London.

Moreover this system has been in operation at Eton for the last five years. The Lancet, dated 17th October, 1874 gives a long

* Plots were sold from £17 15s. to £64 per acre.

All this time Dr. Dyke says, the whole of the sewage streams, 800,000 gals, per day, was being passed through ten acres of prepared land.

page 13 account of the system as adopted there, of which the following is a summary:—

A farm of 50 acres utilizes the sewage of 4500 people. They having as their maximum a water supply of 40 gallons per head. The farm is nearly two miles from the town, with which it is connected by means of cast iron pipes, nine inches in diameter. Two engines (acting on the centrifugal principle) of 8-horse power, pump 80,000 gallons within 8 hours. There is a double sewage filter tank at the pumping station for the removal of solid matter, and a reservoir capable of holding 20,000 gallons, which acts as an equalizing reservoir, so that the pump need not always be at work. To this filter tank the sewage of the town is conveyed by 18-inch pipes, having a fall of five feet in a mile. The old sewage pipes are used for storm water. There is an emergency safety-valve opening into the Thames. The solid matter is mixed with ashes, and the contents of dust bins, and carted directly to the farm. No deoderant is used. During the past five years, says the Report, the sale of the produce has cleared the cost of the superintendence and irrigation. The entire expenditure of these works, including the purchase of the farm, which is freehold, amounted to £20,000. The cost of drainage is covered by an eighteen-penny rate. It is said that no case of typhoid has occurred since these works were formed. I should have mentioned that ventilating pipes are placed at the highest parts of the drain, these pipes running higher than the tallest chimneys. There are also tanks capable of holding a thousand gallons of water, placed in communication with the drains for flushing purposes.

In an article in the "Engineer" dated October 16th, 1874, irrigation is said to be at the top of all systems for the disposal of sewage. It goes on to say that a Committee was appointed to inquire into the best means for the disposal of sewage, and that the Committee, after having examined various systems at various places, report that in no instance where irrigation was tried, did it give an unsatisfactory result. Thus at Leamington, a town having a resident population of 30,000, the sewage is pumped to a height of 32 feet, and delivered to a Home farm of Lord Warwick's, two and a half miles distant. The farm consists of 400 acres, 250 of which are irrigated. The crops are all that can be desired, and Lord Warwick pays £450 a year for the sewage. This last is efficiently disposed of and thoroughly purified, the effluent being bright, possessing nothing noxious, nor unpleasant to the taste. At Doncaster, the results of irrigation are yet more promising, the Corporation receiving £800 a year rent for a sewage farm, 2¼ miles distant, the sewage being pumped to a height of 52 feet.

The article concluded in these words:—"Thus then we have page 14 the verdict of a very painstaking Committee, with every possible facility afforded them, deciding that Irrigation is the only practical way of getting rid of sewage with good results."

In our case, I believe no pumping would be required, if Mr. Burt's plan were adopted; for the pressure of the Water of Leith running through his main sewer would probably be sufficient to propel the contents on to the sand-hills previously lowered and prepared, the effluent water finding its way through the sand into the ocean. It is probable that the Government would grant sufficient of the sand-hills to the Corporation for the carrying out of this scheme, and a letting of these would help materially to defray the primary and working expenses.

In concluding this chapter, I would suggest that the sewer pipes be so constructed, that no exhalations could find their way into our dwellings. In Glasgow, I believe the experiment of burning sewer gas as they would common gas has been tried with success; at all events, such a mode of removing the gas is possible, seeing that it possesses from 70 to 95 per cent, of combustible material, including light carburetted-hydrogen, hydrogen, and carbonic oxide. In a recent number of the "Lancet" it is mentioned that Dr. Aldridge, of Southampton has devised means by which a water-closet may be so constructed as to effectually prevent the escape of sewer gas into it.

Storm and sub-soil waters should not be allowed to enter the sewers, as they have a tendency to obstruct them by the metal which they convey.

Chapter VIII.


Temperature.—Our mean annual temperature is 50-6°; our mean summer 57.5°, our winter 43.07°, Fahr.*

London has a mean annual of 51.0°, a mean summer of 64.0°, a mean winter of 37-0°. The mean annual for Edinburgh is 47.0°, the mean summer 38-0°, and the mean winter 37.0°. For Dublin, the mean annual is 50.0", summer 61.0°, winter 39.0°. In the south-west district of Wales the mean annual is 54.0°, the mean winter being as high as 42.0°. Auckland has a mean annual of 59.0°, Melbourne of 57.0°, Hobart Town of 52.0°, and Sydney of 66.0°.

* Calculated from Government Tables.

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The mean daily range of temperature for Dunedin averages for a year 14.0° Fahr. For a period of seven, the highest mean daily range was 22.0°, the lowest was 8.0°, the former being for a January month, the latter being for a June month. In Scotland 12° is the average mean daily range.*

The physical features of a country have a modifying influence on its climate, in addition to its latitude. Thus our ocean and forests control the mean daily range of temperature, and influence the humidity of our atmosphere.

Rainfall.—Our mean annual rainfall is 31.49 inches. Rain falls on an average upon 148 days in the year, 69.2 of these being what are termed rainy days-i.e., over 0.1 in. falls upon them.

The average rainfall in a year among the western hills of Great Britain and Ireland is 80 to 150 inches; away from the hills, likewise upon the west, 30 to 45 inches; and upon the east it is 20 to 28 inches. In France 30 inches is the yearly average. During our summer months, from the years 1867 to 1873 inclusive, a mean of 9.840 inches of rain fell, the mean for the winter months being 8.323 inches-the greatest rainfall any one day amounting to l.926, with a south-east wind, in a May month.

The mean dew point for seven years, as taken at the Government Observatory, was 42.5°.

The mean humidity for the same period was 76.3°, saturation equalling 100. Our atmosphere is as a rule ¾ saturated with vapour,

The prevailing wind is the west, next south-west, and northeast.

* Buchan on Meteorology.

Taking the atmosphere around the Observatory to be not far different from that in the City.

Chapter IX.

Vital Statistics,

From the 1st of February to the 31st of December last year there were 420 deaths from all causes, being at the rate of 22.7 per 1000 per annum. Of these, 7.7 were due to zymotic-i.e., contagious or infectious diseases. Half of the deaths from zymotic diseases occurred in children under 5 years.

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The greatest number of deaths from zymotic diseases occurred during October, November, December, being principally due to measles.

By leaving these months out of our calculation, we find the annual death-rate to be, from zymotic causes, about 54, and from all causes, 20.3 per 1000 inhabitants, nearly a third of the latter occurring in children under five years of age.

Our annual excess of births over deaths is 29.6 per 1000, being 6.8 above the excess in England and Wales, a sufficient excess to double our population in 24 years.

Our death-rate is high, though out of 628 registration districts nine-tenths yielded a death rate ranging from 17 to 36 per 1000; but, on the other hand, there were 64 districts yielding a death-rate of 15 to 17 only.

A Preliminary Report is scarcely suited for more minute details, the which will be given in future and periodical reports.

Information for January could not be procured.