PERFUME PHOTOTOXICITY 711 Fraction 3A--This fraction was not obtained by preparative TLC but by direct crystallization of the crude C-P mixture. To one volume of the crude mixture, two volumes of ethyl ether was added. A mixture of bergapten and limetriM immediately precipitated, was isolated by filtra- tion, and was recrystallized three times from hot methanol. This frac- tion is included because bergapten is believed to be the compound pri- marily responsible for photosensitization. APPENDIX II COMPARATIVE PATHOLOGY PRODUCED BY SKIN APPLICATION OF OIL OF BERGAMOT IN THE HUMAN, RABBIT, GUINEA PIG, HAIRLESS MOUSE, HAMSTER, AND PIG HOWARD L. RICHARDSON, M.D., AND KENT J. DAvis, D.V.M. DIVISION OF PATHOLOGY, FOOD AND DRUG ADMINISTRATION Hematoxylin-eosin stained paraffin sections of skin taken 6, 16, 24, 48, and 72 hours after topical application of 10% oil of bergamot in 70% alcohol were examined by light microscopy to study species variations in phototoxic reactions. Histopathologic findings, involving furocoumarin phototoxicity in animals, are summarized in Table XI. Except in the case of hamsters, gross appearance of the skin provided the clue to damage in underlying tissues. In severe involvement, the epidermis became acanthotic, some- times edematons, and occasionally necrotic. The reticular dermis showed greater inflammatory cell infiltration than the papillary dermis. The appendages showed slight, immediate involvement, but after a pe- riod of two months, the rabbit had little hair growth in the area of ap- plication and hair follicles became sparse and degenerated in appear- ance. The major changes in the human forearm skin with 72 hours post- bergamot treatment were epidermal necrosis intermixed with areas of epidermal edema and acanthosis, and with necrobiosis of sebaceous glands. The most nearly comparable change noted in skin sections from other animals examined occurred in the corneum-stripped pig skin. Oil of bergamot application to normal pig skin produced no significant microscopic lesions during the 6- to 8-hour observation period. Rabbit skin was also relatively nonreactive microscopically however, two months after application of 0.1% bergapten solution there were decreased num- bers of hair follicles and the few hair follicles remaining or regenerating

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