Dr. Thorne Thorne's report to the local government board on an epidemic of diphtheria at Llanhaiadr.

  • Thorne, R. Thorne (Richard Thorne), Sir, 1841-1899.
Date:
1878
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Licence: Public Domain Mark

Credit: Dr. Thorne Thorne's report to the local government board on an epidemic of diphtheria at Llanhaiadr. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    Si fact that a large oven of a bakery was in use there at the time of my visit; but close by the house is a wall which for the purpose under consideration fairly corresponds with the house walls, and it was quite wet. Within six feet of the house was a heap of dung, and situated at one side of it and at a considerable height above the ground floor was a privy-with-pit, and also a pigstye from which liquid refuse trickled down towards the house door. [Since writing the above I learn that a fatal case of enteric fever has occurred in this house. The disease was not ascertained to have been imported.] . In the third case it is not possible to state whether the girl contracted her illness whilst at the inn, or at her own home. The latter is, however, a house built into the hill side, the loose soil being in immediate contact with the back and side walls. In addition to this a privy having a large pit, the contents of which were freely soaking into the surrounding soil, was found situated at a high level immediately behind the house. A fatal case of diphtheria occurred in this house in 1861. It will thus be seen with regard to these three premises that besides presenting certain gross nuisances fouling their sites, they were all specially characterised by dampness of site, a circumstance which leads me to consider somewhat in detail the physical features of the site which Llanrhaiadr occupies, and the general meteorological conditions of the district. Site and Soil.—The Yale of Clwyd in which Llanrhaiadr is situated commences at Llanfair Chapel, about seven miles south of Pentre, and gradually widening in its course opens at Rhyl on the north coast of Flintshire. The vale consists mainly of a flat level plain between two ranges of hills; it is about 16 miles in length and is traversed by the Clwyd and its tributaries. According to information supplied to me by C. E. De Ranee, Esq., of Her Majesty’s Geological Survey, the Yale is entirely excavated in impermeable Silurian Rocks, which rise to a considerable elevation on either side, and pass under the newer rocks occupying the bottom of the valley, thus forming a water-tight basin through which the Clwyd and its tributaries flow. These newer rocks consist of Old Red Sandstone and of Moun- tain Limestone flanking the sides, and of the Triassic Lower Mottled Sandstone occupying the bottom of the valley. These are all permeable strata, and would absorb a large amount of the rainfall of the district, were it not that they are covered by a thick envelope of impervious glacial drift, which appears originally to have filled up the valley to a height of 500 feet or 600 feet above the sea level, and to have been subsequently to a great extent carried away by post-glacial fluviatile denudation, which has re-excavated the valley and re-assorted the materials which filled it up, so as to distribute them in an alluvial plain, and in older alluvial terraces which fringe the valley at successive heights. From the area occupied by the rocks flanking the sides of the Vale, and from the Silurian rocks in the upland tract above, the rainfall, to no note- worthy degree lessened by absorption, is thrown off into the valley, the permanent water- level of which appears to be very little below the ordinary top-water level of the Clwyd. (See diagrams annexed showing sections across the Yale of Clwyd.) For a space of between two and three miles in the neighbourhood of Llanrhaidr the drift, which consists of loamy clay charged with stones closely packed together, is stated to be “ wholly impermeable.” “ Flourishing oak trees, the growth of rushes, dark-coloured “ grass, deep and full ditches, all attest the clayey nature of the soil and its non- “ absorbent qualities.” A large portion of this area is also beneath the level of the floods, which often cover the fields and the roads around. Rainfall.—Ho meteorological records are kept at Llanrhaiadr; but from those of various observers in the neighbourhood which have been supplied to me, and especially from those recorded by Lieut.-Colonel Humberstone, of Glan-y-wern, a place situated in the Yale of Clwyd, about two miles east of Llanrhaiadr, I have been able to gather the following points as to rainfall. The average fall of rain in this part of the Yale for the months of July and August has for a series of years been 2'3 in. and 2-2 in. respectively. In July 1877 it was 2’9 in., and in August it reached 5-24 in. In the month of July nearly two inches of rain fell on the three days 13th-15th, and somewhat over an inch fell again on the 24tli and 25th. This, however, under the peculiar physical conditions already named, led, I am informed, to some flooding of the Yale in the vicinity of Llanrhaiadr, towards the end of July. How far the floods subsided I cannot learn; but they were much increased by the exceptional rainfall which, commencing on the 3rd of August, was maintained almost throughout the month. The wetness thus induced was moreover a foul wetness, for the sewage of Llan is held back for many months of the year in streamlets the level of which is below the ordinary level of the river Clwyedog, a tributary of the Clwyd; but when these rivers overflow