and Water used for General Purposes. 
153 
3. The proportion of oxldisable organic matter in sample 
No. 1 is inconsiderable, and in sample No. 2 very large. 
4. Both samples are largely impregnated with common salt. 
5. Sample No. 1 contains a considerable amount of nitrates, 
and sample No. 2 only traces of nitrates. 
It appears from these results that both samples are contami- 
nated with drainage products, which render both unwholesome, 
and fully account for the outbreak of typhoid fever in the 
family. Although No. 2 contains only traces of nitrates, it is, 
nevertheless, the worse of the two samples, for it contains a 
much larger proportion of unoxidised organic matter, and more 
ammonia than No. 1 ; and the organic impurities which found 
their way into the wells from which the samples were drawn 
having undergone a more perfect oxidation in No. 1 than in 
No. 2, exist in the former sample in a less dangerous condition 
than in the latter. The amount of nitrates in different samples 
thus must not be regarded as the measure of their relative purity. 
Fresh sewage or drainings from dung-heaps I find contain no 
nitrates whatever, and hence the absence of nitrates, or the 
occurrence of mere traces, does not prove that a water is whole- 
some. On the contrary, the absence of nitrates, and the simul- 
taneous presence of much unoxidised organic matter, of chloride 
of sodium (common salt), and appreciable quantities of saline 
and organic ammonia in a water, show that it is contaminated 
with the most objectionable and decidedly injurious organic 
impurities. 
These examples might suffice for having directed general 
attention to the frequent use which is made of unwholesome 
drinking-water in country districts ; and I may observe, that 
scarcely a week passes in which I do not receive a sample of 
water from the country which, on analysis, proves to be injurious 
to health, by being contaminated with imperfectly oxidised 
drainage products. I cannot refrain, however, from directing 
attention to one additional case in point, which has quite recently 
been brought under my notice. A gentleman residing in Lin- 
colnshire recently lost two beasts. The veterinary surgeon who 
was consulted was unable to account satisfactorily for the cause 
of the death of the animals, but thought it probable that the 
water given to them may have contained something injurious to 
health, or have been deficient in some important element. A 
sample of the water was consequently sent to me, and my 
opinion was solicited as to the effect the water was likely to 
have had on the deceased beasts. The water in question was 
coloured slightly yellow, and contained some light floating 
particles of matter of apparently organic origin, but it was free 
from smell. The residue which was left on evaporation was 
