154 SEEDS 



Description. Cocoa seeds, as they occur in commerce, are about 

 2-5 cm. in length and of a flattened-ovoid shape. The seed-coat is 

 reddish brown or chocolate brown in colour, thin and brittle. It can 

 easily be separated from the kernel, which consists mainly of two 

 irregularly folded, chocolate-coloured cotyledons ; the latter are so 

 brittle that they easily separate into small angular fragments (cocoa 

 nibs of commerce). 



Constituents. Both the kernels and the shells contain the alkaloid 

 theobromine, the former yielding about 2 per cent., the latter about 

 1 per cent. The kernels contain, further, about half their weight 

 of solid fat, which is obtained as a by-product in the manufacture of 

 cocoa essences by submitting the heated seeds to strong pressure 

 (Oleum Theobromatis) . The seeds also contain a trace of volatile oil. 



Theobromine or dimethylxanthine, C 5 H 2 (CH 3 ) 2 N 4 2 , lias been obtained as 

 a white crystalline powder very slightly soluble in cold water or alcohol, more 

 readily in boiling. It sublimes at 290, and combines readily with alkalies 

 and alkaline earths to form salts. By introduction of the methyl group it is 

 converted into trimethylxanthme (caffeine). 



Oleum Theobromatis is obtained as a by-product in the manufacture of cocoa 

 and chocolate. The seeds are first roasted, then broken and the shell and 

 embryo removed ; the resulting cocoa nibs are ground in horizontal burr mills 

 during which sufficient heat is developed to liquefy the fat. The mass (cocoa 

 mass) is then pressed, the expressed oil filtered and run into moulds to set. It 

 forms a hard, yellowish-white solid, melting at 30 to 33, consisting chiefly 

 of the glycerides of stearic (40 per cent.), palmitic, and oleic acids existing 

 partly at least as mixed glycerides, i.e. glycerides in which two or more of these 

 acids are combined with one glyceryl group. See also ' Oil of Theobroma.' 



5. Cocoa is largely used as a more nutritious and less 

 stimulating beverage than tea or coffee. Its principal active 

 constituent, theobromine, has an action similar to that of caffeine, 

 but while its effect on the nervous system is less than that of caffeine 

 its diuretic action is greater. 



GUARANA 



(Pasta Guarana) 



Source, &c. Guarana is prepared from the seeds of Paullinia 

 Cupdna, Humboldt, Bonpland, and Kunth (N.O. Sapindacece) , an 

 elegant climbing shrub indigenous to and common in Brazil, especially 

 in the basins of the Amazon and its tributaries. It derives its name 

 from the Guarinis, an aboriginal tribe of Indians. The difficulty of 

 collecting the seeds from the wild plants, which, though common, are 

 not easily accessible, has apparently led to their cultivation, the 

 plants being trained to poles like hops. When the pods open to 



