Page 15 - Pharmacy History 34 February 2008

For Pereira, water hardness was another consideration. He states that hard water is a ‘less perfect solvent of organic matter than soft water; hence, in the preparation of infusions and decoctions, and for many economical purposes, as for tea-making and brewing, it is inferior to soft water; and, for the same reason, it is improper as a drink in dyspeptic affections.
Moreover, it proves injurious in urinary deposits. The unfavourable effects of hard waters are especially manifested in horses.’
The problem with lakes, streams and rivers was that, although they might have appeared clear and pure, they were often used as open sewers for villages, towns and cities. Despite this, the River Thames, containing Vibrio cholerae and Salmonella typhi, was London’s main source of drinking water.
According to ‘Table traits, with something on them’ by John Doran (1854), water from the Thames was ‘offensive to the sight, disgusting to the imagination and destructive to the health’. Pereira states: ‘Thames water, when taken to sea in casks, soon becomes putrid and offensive, and evolves inflammable vapour.’ This was due to gases formed from organic material decomposing. (A similar comment could no doubt be made against Melbourne’s water supply which came from the River Yarra, which itself was the main sewer serving the city. Ed)
Filters
Perhaps the greatest innovation in the 19th Century for the production of water suitable for drinking and for the
manufacture of official pharmaceutical preparations was the development of water filters. It is believed that as early as 1827, Henry Doulton was working on the development of ceramic filters which would remove bacteria from drinking water.
Traditionally, filters for water were composed of layers of substances
such as sponge, gravel and charcoal. These filters could not be cleaned and had to be renewed. Doulton’s filters were made from various earth and
clay materials and could be scrubbed clean and re-used. Queen Victoria was impressed and, in 1835, commissioned Doulton to produce a water filter for the Royal household.
In 1862, Doulton introduced a manganous carbon filter and was able to manufacture filtering apparatus for commercial and domestic use, many of which were highly decorated.
The next development by Doulton was in the use of diatomaceous earth, also known as kieselguhr, to produce ceramic filters. This is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white or off-white powder and has a high silica content. It is composed of the shells of diatoms — pre-historic, algae-like creatures.
Dampened and fired it produces a filter capable of removing 99% of water-borne bacteria. The filters were cast in the shape of candles with a hollow centre closed at one end and these were enclosed in a lidded vessel. Water permeates through the filter and is carried off through the empty centre of the candle. This principle is still in use today in industrial filtration.
In 1901 Doulton was knighted and in 1902 he was conferred the royal warrant and the right to use ‘royal’ in front of his company’s name for his work on drinking water filtration. However, Doulton was not the only manufacturer of filters. Operating in the second half of the 19th century was the Silicated Carbon Filter Company in Battersea, London.
The company manufactured filters which, in an advertisement in Chemist and Druggist, it describes as ‘the most effective means known of purifying water for domestic, manufacturing and general purposes.’ Its range included pocket-sized filters for travellers and it published an analysis of the effect of the silicated carbon filter upon Thames water obtained near Battersea Bridge at high water (see Table below).
In Chemist and Druggist, of 14 March, 1868, the company had announced:
The filtering media employed in the manufacture of these Patent Filters consist of an intimate combination of carbon, in its most effective form, with minutely divided silica, as these substances exist in the celebrated Torbane Hill mineral; and it has been satisfactorally demonstrated that this compound, prepared under the patent process, is immensley MORE EFFECTIVE in the purification
of water than carbon, both as an oxidiser and as a promoter of chemical combination generally.
It also claimed the advantages of its filters included that:
•
They removed all colour, taste, and odour arising from the decomposition of organic matter, and rendered the most noxious gases harmless
Table: Effect of the silicated carbon filter
Unfiltered
Filtered
Total solid contents of an imperial gallon (about 4.5L)
33.5 grains (2.2g)
8.7 grains (0.6g)
Hardness, as determined by Clark’s test
13 degrees
6 degrees
Earthy carbonates deposited by boiling one gallon
11 grains
None
Organic matter contained in an imperial gallon
3.8 grains (0.2g)
0.6 grains (39mg)
volume 4 no 35 September 2008
Pharmacy History Australia 15