PENNYROY′AL. Syn. Pulegium (Ph. L. & E.), Mentha p. (Ph. D.), L. “The recent and dried flowering herb of Mentha pulegium, Linn.” (Ph. L.) Pennyroyal tea is a popular emmenagogue, expectorant, and diaphoretic, and is in common use in asthma, bronchitis, hooping-cough, hysteria, suppressions, &c. Water, essence, oil, and spirit of pennyroyal are officinal. They are now chiefly used as mere adjuncts or vehicles.
PENTASTOMATA. There are two varieties of this entozoon—the Pentastoma denticulatum, which Leuckart has shown to be the larvæ of the Pentastoma tænoides, and the Pentastoma constrictum. The P. denticulatum infests the human liver and small intestines. The P. constrictum does not appear to be known in this country. The latter appears to have caused death by setting up peritonitis. According to Dr Aitken these parasites are provided with two pairs of hooks or claws, placed on each side of a pit or mouth, on a flattened head. He says: “These claws appear to be implanted in socket-like hollows or depressions, surrounded by much loose integument. These socket-like hollows appear to be elevated on the summit of the mass of tissues which lies underneath the folds of integuments surrounding the base of the hooks. These parts are regarded as the feet of the parasite,
and the hooks are the fore claws. The pit or mouth is of an oval shape, the long axis of the oval lying in the direction of the length of the worm.
“The less or outer margin of the pit is marked by a well-defined, thin line. There are no spines nor hooks on the integument of the elongated body.”
PEPPER (Black). Syn. Pepper; Piper, B. P.; Nigri baccæ, Piper nigrum (Ph. L., E., & D.), L. “The immature fruit (berry) of Piper nigrum, Linn., or the black pepper vine.” (Ph. L.)
Pur. The ground black pepper of the shops is universally adulterated; in fact, the public taste and judgment are so vitiated that the pure spice is unsaleable. A most respectable London firm, on commencing business, supplied their customers with unadulterated ground pepper, but in 3 cases out of every 4 it was returned on their hands and objected to, on account of its dark colour and rich pungency, which had induced the belief that it was sophisticated. The house alluded to was therefore compelled by the customers to supply them with an inferior, but milder and paler, article. The substances employed to lower black pepper are known in the trade as—‘P. D.,’ ‘H. P. D.,’ and ‘W. P. D,’—abbreviations of pepper dust, hot pepper dust, white pepper dust. The first is composed of the faded leaves of autumn, dried and powdered; the second, the ground husks (hulls) of black mustard, obtained from the mustard mills; and the third is common rice, finely powdered. Equal parts of black peppercorns, H. P. D., and W. P. D., form the very best ground pepper sold. The ordinary pepper of the shops does not contain more than 1⁄8th to 1⁄6th of genuine pepper, or 2 to 21⁄2 oz. in the lb. Very recently, ground oil-cake or linseed meal has been chiefly employed as the adulterant, instead of the old ‘P. D,’
Dr Parkes[92] says: “The microscopic characters of pepper are rather complicated. There is a husk composed of four or five layers of cells and a central part. The cortex has externally elongated cells, placed vertically, and
provided with a central cavity, from which lines radiate towards the circumference; then come some strata of angular cells, which, towards the interior, are larger and filled with oil. The third layer is composed of woody fibre and spiral cells. The fourth layer is made up of large cells, which towards the
interior become smaller and of a deep red colour; they contain most of the essential oil of the pepper. The central part of the berry is composed of large angular cells, about twice as long as broad. Steeped in water, some of these cells become yellow; others remain colourless. It has been supposed that these yellow cells contain piperine, as they give the same reaction as piperine does; namely, the tint is deepened by alcohol and nitric acid, and sulphuric acid applied to a dry section causes a reddish hue.” (Hassal.)