580 PIPERACE^. 



black pepper exhibits a soft yellowish epidermis, covering the outer 

 pericarp. This is formed of a closely-packed j^ellow layer of large, 

 mostly radially arranged, thick-walled cells, each containing in its 

 small cavity a mass of dark-brown resin. The middle layer of the 

 pericarp consists of soft, tangentially-extended parenchyme, containing 

 an abundance of extremely small starch granules and drops of oil. The 

 shrinking of this loose middle layer is the chief cause of the deep 

 wrinkles on the surface of the berry. The next inner layer of the 

 pericarp exhibits towards its circumference tangentially-arranged, soft 

 parenchyme, the cells of which possess either spiral striation or spiral 

 fibres, but towards the interior loose parenchyme, free from starch, 

 and containing very large oil-cells. 



The testa is formed in the first place of a row of small yellow 

 thick-walled cells. Next to them follows the true testa, as a dense, 

 dark-brown layer of lignified cells, the individual outlines of which are 

 undistinguishable. 



The albumen of the seeds consists of angular, radially-arranged, 

 large-celled parenchyme. Most of its cells are colourless and loaded 

 with starch ; others contain a soft yellow amorphous mass. If thin 

 slices are kept under glycerin for some time, these masses are slowly 

 transformed into needle-shaped crystals of piperin. 



Chemical Composition — Pepper contains resin and essential oil, 

 to the former of which its sharp pungent taste is due. The essential 

 oil has more of the smell than of the taste of pepper.^ The drug yields 

 from 1'6 to 2-2 per cent, of this volatile oil, which agrees with oil of 

 turpentine in composition as well as in specific gravity and boiling 

 point. We find it, in a column 50 mm. long, to deviate the ray of 

 polarized light 1°'2 to 3°'4 to the left. 



The most interesting constituent of pepper, Piperin, which pepper 

 yields to the extent of 2 to 8 per cent., agrees in composition with the 

 formula C^'H^NO^ like morphine. Piperin has no action on litmus 

 paper ; it is not capable of combining directly with an acid, yet unites 

 with hydrochloric acid in the presence of mercuric and other metallic 

 chlorides, forming crystallizable compounds. It is insoluble in water ; 

 when perfectly pure, its crystals are devoid of colour, taste and smell. 

 Its alcoholic solution is without action on polarized light. Piperin may 

 be resolved, as found by Anderson in 1850, mto Piperic Acid, G^'WO*, 

 and Piperidine, C^H"N. The latter is a liquid colourless alkaloid, 

 boiling at 106 ° C, having the odour of pepper and ammonia, and directly 

 yielding crystallizable salts. 



Besides these constituents, pepper also contains some fatty oil iu 

 the mesocarp. Of inorganic matter, it yields upon incineration from 

 4'1 to 57 per cent. 



Commerce — Singapore is the great emporium for pepper, of which 

 1 97,478 peculs (26-J million lb.) were imported there in 1 877. The largest 

 part of it finds its way to England. The import of pepper into the 

 United Kingdom during 1872, was 27,576,710 lb. valued at £753,970. 



» As noticed by Rheede in 1688 : "... ever obtained long before by Valerius 



oleum ex pipere destillatum levem piperis Cordus, Guintherus Andernacensis and 



odorem spirans, saporis parum acris." — Porta (see our article Cortex Ciunamomi, 



Ilort. Malab, vii. 24. — The oil was how- page 526). 



