Thrush
This is another trouble with which the mule is afflicted. Cut away the
parts of the frog that seem to be destroyed, clean the parts well with
castile-soap, and apply muriatic acid. If you have not this at hand, a
little tar mixed with salt, and placed on oakum or tow, and applied,
will do nearly as well. Apply this every day, keeping the parts well
dressed, and the feet according to directions in shoeing, and the
trouble will soon disappear.