When pentachloro-naphthalene was administered per os in exptl. Hereford heifers, 2-8 g./day, typical symptoms developed excessive lacrimation, diarrhea, polyuria, marked salivation, serous nasal discharge, chronic cough, poor appetite, macules of the buccal epithelium, as well as hyperkertosis of the skin, thrown up in rolls and developing fissures, on the sides of the neck, across the withers, and around the mammary glands. Microscopic changes of kidneys, liver, pancreas, stomach, and hair follicles were similar to those in field cases.