This section is from the book "The Volatile Oils Vol2", by E. Gildemeister. Also available from Amazon: The Volatile Oils.
According to H. Thorns2), the oil of Piper angustifolium var. Ossanum, C. DC. (yield 0,87 p.c), contains only traces of phenol ether. When distilled in vacuum, a camphor mixture separated, which melted at 195°, and which presumably consisted of camphor and borneol.