IIOLDO. 291 



beyond the epidermic tissue into the parenchyma. The parenchyma 

 is divided into two zones, one having oval-oblong cells, gorged with 

 chlorophyll, the principal axis of which is perpendicular to the 

 surface of the upper epiderm ; the other having polyhedric cells, 

 less green than the others, containing in the interior thinly 

 scattered grains of chlorophyll. Both zones are furrowed by the 

 fibro- vascular tissue proceeding from the nerves of the limina, and 

 in the second moderately large lacunye frequently occur. The 

 vessels containing the essential oil are found principally in the 

 latter zone ; rarely they occur in the former. The oil vessels differ 

 in shape from the neighbouring cells, being perfectly spherical and 

 of a greater diameter, and this form remains the same in wdiatever 

 part they are found. There is no trace of chlorophyll in the 

 interior, but sometimes the thick enveloping membrane retains 

 small green granulations, and the rest of the cavity is filled with 

 a refracting liquid. In places where this membrane has been cut 

 by the razor its texture appears close, firm, and transparent, and 

 the liquid may be seen protruding beyond the envelope. This 

 liquid is white, and transparent in the green leaf ; in the dried leaf 

 it has a yellowish oreen tint, and does not fill all the cavitv, being 

 divided into little drops, imprisoned at the bottom of the organ. 

 Cells containing essential oil are met wdth in nearly every part of 

 the plant." 



On making a chemical examination of the imported leaves, 

 Verne states that " some leaves mixed with portions of the stem, 

 coarsely powdered, were placed in a displacement apparatus, and 

 treated successively with ether, alcohol, and distilled water. 

 Treated with ether, they yielded 2 per cent, of essential oil, a trace 

 of alkaloid and citric acid, and an aromatic substance (probably 

 resin). To the alcohol they yielded a small quantity of essential oil, 

 alkaloid (abundantly precipitated by double iodide of mercury and 

 potassium), citric acid, sugar, and aromatic matter. To the distilled 

 w^ater they yielded sugar, gum, citric acid, and tannin. The 

 abundant proportion of essential oil (2 per cent.) was obtained in 

 repeated operations. On distillation, a certain quantity of oil 

 having an odour resembling that of the plant, passes over at 185^ 

 C. ; the thermometer then rises gradually to 230° C, and after 

 remaining stationary a few moments, rises to 300° C. The products 

 of distillation, collected at 230° C, and between 230° and 300° C, 

 compared with the first product, have a greater density and a 



