On September 10, 1967, an aged mare was presented to the Iowa State University Veterinary Clinic with a history of progressively losing condition. In early June the owners had noticed a white mucus-like substance being passed from the lips of the vulva. This secretion was not associated with urination. by the end of June, the discharge had ceased, but the animal continued to become weaker and thinner. The mare was wormed in July and placed on a special high-protein diet in an effort to return her to her original condition. Throughout the course of the summer, the mare maintained an excellent appetite