THEOBROMINE 437 



0.4 mm. to 4 mm. They are said to be decomposed, at least in part, 

 on washing with either alcohol or water. The Pharmacopoeia 

 Helvetica gives the following micro-chemical test for determining 

 the presence of caffeine in cola: Transverse sections of the cotyledons 

 are placed in strong hydrochloric acid and slightly heated; then one 

 or two drops of a solution of gold chloride are added and the sections 

 pushed to one side. The liquid is allowed to evaporate and near 

 the edge of the residue branching groups of needles of caffeine gold 

 chloride separate. 1 



Theobromine (dimethyl-xanthine) also occurs in cacao and 

 crystallizes in rhombic prisms, which are sparingly soluble in water 

 and alcohol, the solutions being slightly acid. It sublimes on heating 

 without decomposition, and forms crystallizable salts with mineral 

 acids, which are readily decomposed with water. Theobromine on 

 treatment with methyl iodide yields caffeine. Both caffeine and 

 theobromine are also prepared synthetically. 



Fresh kola nuts also yield from 0.3 to 0.4 per cent of a crystalline 

 tannin-containing substance, kolatin, which is combined with the 

 caffeine as kolatin-caffeine. The latter is unstable and is easily 

 decomposed on curing or drying the drug. Kolatin resembles pyro- 

 catechin in its reactions and appears to neutralize the physiological 

 action of caffeine, and hence the dried kola nuts are more active than 

 the fresh nuts. 



The red color in dried kola seeds is due to an oxydase similar to 

 that which causes the darkening of apples when freshly cut and 

 exposed to the air. If the seeds are first heated in boiling water 

 for 30 minutes and then dried they do not darken. 



Allied Plants. The seeds of a number of other plants are said 

 to be sometimes admixed with kola, and of these the following may 

 be mentioned : Cola Ballayi, a plant growing in the Gaboon, the seeds 

 of which contain six cotyledons and are deficient in alkaloids. The 

 seeds of Garcinia Cola (Fam. Guttiferse) have been substituted for 

 Cola under the name of " Staminate Cola." These seeds do not 

 contain caffeine, but two resins which seem to have a physiological 

 effect similar to Cola. The seeds of Pentadesma butyraceum, of 

 Sierra Leone, have also been used as a substitute for Cola; they 

 contain a fat, having a turpentine-like odor, which is used by the 

 natives in place of butter, and hence the tree is known as the " Butter 

 or Tallow tree." 



CACAO. Cocoa. The prepared kernels of the ripe seeds of 



1 For photomicrographs of crystals of caffeine gold chloride, consult Kraemer's 

 Applied and Economic Botany, p. 163. 



