232 PLANT ORGANS OR PARTS OF PLANTS. 



ripe fruit. They are very minute, averaging i to 5 

 microns, and are simple and compound in twos, threes, 

 and fours. The crystal masses are very distinctive ; they 

 vary greatly in size and are sometimes very common in 

 the powder, at other times not. Specimens mounted 

 in glycerine jelly will not be preserved, if the jelly in 

 preparation is heated above 125^ C. The parenchyma 

 is usually thin-walled and very irregular ; in the region of 

 the pericarp many of the cells are pitted and the walls are 

 thicker, the cells being somewhat smaller, 30 to 40 microns. 

 The cells of the endosperm are thinner- walled, average 

 about 40 microns, and are not pored. Epidermal struc- 

 tures are distinctive though not prominent. The thickened 

 walls, which are finely striated, are readily recognized. 



The fibro-vascular elements are not numerous, yet 

 almost always present in any small field. Spiral vessels, 

 tracheids, tracheid-like stone cells, and short fibres are 

 constant and some sieve tube elements may be found. 

 The greater the quantity of stems, the more vascular and 

 fibrous elements are found. 



Chemistry. — Fresh cubebs contain about 10 to 16 per 

 cent, of ethereal oil, which is contained for the most part 

 in the glands. This oil consists in the main of various 

 terpenes, with the general formula C^Ji^v Cubebin, 

 CjoHjoOg, is found in amounts varying from i to 2.5 or 3 

 per cent. It is a slightly bitter, colorless, and odorless 

 crystalline body, colored red by concentrated sulphuric 

 acid. It crystallizes in white needles, which have a 

 melting-point about 125° C. Cubebin is usually mixed 

 with the resin, which is found in percentages of about 5 

 to 7. There is, further, about 8 per cent, of gum and i per 

 cent, of fatty oil. 



PIPER. PEPPER. 



The unripe fruit of Piper nigrum, Linne (nat. ord. 

 Piperacece), a native of India and Cochin-China, culti- 

 vated in the East Indies. 



