27 
where electricity was cheap it was very economical. But, 
of all the artificial treatments to which water was subjected, 
storage was probably the most simple, and yet the most 
effective. It had been found that by storage the organisms 
gradually diminshed, and that the pathogenic types perished 
fairly early, being unable to survive under these conditions 
for any prolonged period. On distribution, the water might 
be altered by further sedimentation in the service pipes, 
or growths might begin to flourish which altered the charac- 
ter of the water as regarded its appearance, taste, or odour, 
or the number of organisms it contained ; but it was extremely 
unlikely and seldom that any further organic contamination 
took place after the water had left the service reservoir. 
There were certain diseases which were conveyed by water, 
and known as water-borne. Water played its part by 
carrying the organisms producing the disease, and such exam- 
ples were cholera, dysentery, and typhoid fever. Again, 
the water contained small organisms, spoken of as animalculse, 
which acted as intermediate hosts to certain parasites, and 
we had the diseases resulting from the guinea worm and the 
malaria parasite. Waters carrying the ova and embryos of 
certain worms were known to produce diseases in Egypt and 
India, but these were not known, fortunately, to occur, in 
England. Some waters contained fine suspended matters, 
which acted as intestinal irritants, and so caused diarrhoea. 
Others contained dissolved salts, and were generally 
characterised by producing diarrhoea, whilst others produced 
constipation. Others, again, were said to give rise to 
conditions of goitre. Lack of certain salts in some waters 
had condemned them as being unsuitable for young children. 
Another important matter, which often was overlooked, was 
lead poisoning, caused by the water attacking the leaden service 
pipes, and so becoming contaminated with lead compounds, 
either in solution or in suspension. The waters which were 
naturally the purest were generally those which exhibited 
this dangerous quality in the most marked degree Treat- 
ment for a defect like this, whilst simple, required to be 
carried out with caution, and was in the end efficiently 
economical, because of the great blessing which it conferred 
on the consumers. 
