Nothing is more important to the well-being of breeding-studs than a supply of wholesome water. It is not to be expected, save under exceptional circumstances, that a public service will be available. Ponds, rivers, wells, and streams are the more common sources from which the supply will require to be drawn. Here it will be necessary to look into the details of these sources in all their relations, and particularly as to whence they are fed or replenished, and in what relation they stand to possible sources of contamination with matters prejudicial to health.

Rivers on whose banks manufacturing industries are carried on, are liable to be polluted with various deleterious waste products of manufacture, and the danger to animal health will in such cases be in proportion as the stream is slow and small in volume, or rapid and large. In times of drought, when water is low and sedimentary matters come to the surface and are stirred up by the feet of horses while drinking, the danger is materially augmented, not only as regards chemical substances and decomposing organic matter, but also in reference to parasitic infection. Large numbers of animals are sometimes ruined in health or altogether destroyed by the last-named cause. More than one costly stud, in the experience of the writer, has been seriously depleted in consequence of exposure to ponds infested with the eggs and larvae of bloodsucking parasites.

Ponds should be periodically cleansed. No trees should be allowed to overhang them, and to obtain the greatest security against mischief they should be fenced off and the water lifted into tanks placed beside them. This is especially desirable during periods of drought, when they are low, and the decomposing sediment teeming with animal and vegetable life is brought near to the surface.

Purity is not a possible condition in nature, and cannot therefore be hoped for, but as far as practicable an ample and wholesome supply should at all times be accessible to breeding-stock and their produce.

Neglect of this precaution has frequently been found by the writer to afford a reasonable explanation of those outbreaks of abortion and infertility which so frequently occur in our large breeding-studs, and it should ever be present to the mind of the breeder that however wholesome water may be at its source and in its course, dangerous pollution may nevertheless result where tanks and troughs are allowed to be fouled by animal and vegetable matters. The periodical cleansing of these receptacles, therefore, is indispensable to good management and success in breeding operations.