The whole of the urinary channels being lined by mucous membrane, it is not remarkable that mucus should be found in healthy urine. Sometimes, however, it exists in such amount as to render the fluid thick and ropy, and to impart to it the consistence of thin glue.

This condition is not necessarily associated with serious organic disease, but rather with a state of irri-tability of the urinary organs generally. It is most frequently seen in old animals, and especially mares. When submitted to microscopical examination the urine in these cases is found to contain small mucous corpuscles entangled in a sticky fluid, together with a number of fine filaments studded with minute granules of carbonate of lime. The latter are derived from the kidney, and represent casts of the urine tubes in which they have been formed.