A one-year-old male cocker spaniel was presented to Stange Memorial Clinic on Feb. 15, 1952, with a history of having been vaccinated four days earlier with 25 mg. of distemperoid virus. Since the vaccination, the animal had shown vomition, salivation, diarrhea and had refused all food except milk and meat. The owner said the dog had trembled when lying down at rest. The reaction started approximately 12 hours following vaccination.