EUCALYPTUS. 20I 



Spiral annular or reticulated types. The fibres are for 

 the most part comparatively short ; those in the Huanuco 

 coca being stouter and stronger than those in the Truxillo. 

 A few starch grains may be found and some oil droplets. 



Chemistry. — The important constituents are the two 

 alkaloids, cocaine and hygrine, together with tannic acid 

 and wax. 



EUCALYPTUS. 



" The leaves of Eucalyptus globulus, Labillardiere (nat. 

 ord. Myrtacecc), collected from the older parts of the 

 tree." 



This is a giant tree, native of Tasmania and Australia, 

 but now cultivated in California and southern Europe. 

 It attains a height of 60 or loo m. and a circumference of 

 10 to 15 m. 



Description. — The leaves are of two kinds; of these, 

 only the older are official. They are thick, 15 to 30 cm. 

 long, about 4 cm. broad, oblique and rounded at the base, 

 borne on long, flat, frequently twisted petioles, in shape 

 falcate, lanceolate, outline entire. Both surfaces are 

 smooth and leathery. Color, greenish-gray, showing, 

 when held to the light, translucent dots of oil-glands. 

 The midrib is slightly prominent, the secondary veins 

 parallel, united at the ends to two undulating marginal 

 veins. The surface is marked with brown dots of sub- 

 erized tissue. Odor, when bruised, strongly aromatic, 

 camphoraceous ; taste pungent, aromatic, slightly bitter. 



Histology. — The epidermis, of several rows of strongly 

 cuticulated, flattened cells, polygonal in outline, covering 

 a single row of larger, less thickened cells, in accordance 

 with the vertical position of the leaves on the tree, is alike 

 on both surfaces of the leaf. Stomata are plenteously 

 present on both sides. Within the epidermis are two or 

 three rows of palisade cells, containing chlorophyll. 

 Among the palisade cells near the epidermis are numerous 

 large, round oil-glands. In many places the palisade 



