157 
WATER, AND ITS IMPURITIES. 
[From “ The Lancet.”] 
IgUr This constitutes one of the articles now furnishing by 
“ The Analytical Sanitary Commission” to The Lancet, whose 
researches promise to afford so much useful and important 
information, not to medical men alone, but to the com- 
munity at large. Nor is the veterinary world likely to go 
wholly unbenefitted by it in their management and treatment 
of the domesticated portion of the brute creation ; since we all 
know how very large a proportion water constitutes of the 
ingesta, in particular of horses. A horse will drink two pailsful 
of water daily, each pail holding three gallons. This will 
amount to forty-two gallons a week, and to the enormous 
quantity of 2184 gallons annually. Surely, it must make a 
difference whether this water be “ good” or “ bad ! ” Water 
has, indeed, frequently produced disease, and now and then 
has occasioned the death of animals. — Ed. Yet. 
The Impurities of Water. 
The various contaminations to which water is liable may all 
be arranged under two heads, and are either organic or in- 
organic . 
Organic Impurities . 
The organic impurities again naturally resolve themselves 
into the dead and the living. 
Dead Organic Impurities. — Inasmuch as the dead organic 
substances present in impure waters form the material or food 
upon which the living impurities are sustained, it is proper to 
allude first to them. 
The dead organic contaminations again admit of still further 
division into those derived from the vegetable kingdom, or dead 
vegetable impurities, and those from the animal kingdom, or 
dead animal impurities. 
Dead Vegetable Impurities. — The dead vegetable substances 
very frequently present in impure water are water-plants, leaves 
and other fragments of land plants, which find their way into it 
in a variety of ways, and at certain seasons, particularly at the 
period of the fall of the leaf. 
These dead vegetables tissues are in a state of continual decay 
and change : deprived of life, they become subject to the action 
of the laws of chemical affinity, by which their structure is 
