Water in Relation to Health and Disease. 
749 
Pollution of Ponds. 
Ponds, like streams, afford immense advantages to owners 
of stock, and, like them also, they sometimes prove a source of 
serious loss. 
Very few indeed realise the evil consequences resulting from 
these generally ill-conditioned stores of water, and when this 
knowledge is brought home to the farmer by bitter experience 
it cannot be said to exercise any far-reaching influence in the 
cause of sanitation. The importance of the lesson irresistibly 
forced upon the sufferer seldom evokes more than a passing re- 
cognition from the less interested neighbour. 
These places, although indispensable, are often little better 
than plague-spots, and thousands of young animals in particular 
die every year from parasitic infection incurred by drinking from 
them. 
It has fallen to our lot to witness many valuable studs and 
flocks crippled and curtailed from this cause, and, by acting upon 
our knowledge of parasitic life, to prevent a recurrence of the 
disease. 
The larvae or young of some of the most destructive parasites 
take up their abode in the mud and organic filth in which ill- 
kept ponds abound. 
The blood-sucking Strongylus contortus , a parasite which 
causes immense losses in our lamb flocks, as well as other nema- 
tode worms, revel in the dirt of our ponds, in slow-running 
streams, and swampy places. 
How they get there will be understood when it is remembered 
that our farm animals frequently deposit their excrement, and 
with it the eggs or embryos of various parasites, in and about 
the water from which they drink. That these organisms sub- 
sequently find their way into the bodies of other animals is in a 
great measure due to the fact that stock are usually permitted 
to w r alk into ponds for some distance to procure their water, and 
in doing so the mud and such parasites as it contains are 
stirred up and swallowed in the act of drinking. 
The remedies against parasitic infection of pond water can 
never in all cases be complete, but by providing a proper slope 
and laying brick earth or some other such matter at their 
entrance, and fencing them across so as to prevent stock from 
going into them, some degree of security might thus be in- 
sured. Where these provisions are not obtainable, thorough 
cleansing at every favourable opportunity should be resorted to. 
This leads us to remark that mud removed from ponds should 
not be used for dressing pasture land immediately, but should 
