( 207 ) 



bica ; one would, therefore, be inclined io lliink lliat cafFcinc and 

 theobromine may again take pari in the internal nuilalioii. 



Let ns, therefore, lake the case ol" a faii-ly yoHiii>- iioii-hlossomini; 

 specimen of Kola acnminata. 



During the unfolding of the 3'onng buds the plant is veij rich in 

 cafleine and theobromine; the young leaves and branches, however, 

 retain these substances for a short time ojdy, so that after two months 

 they have completely disapi)eare(l. There is then not a single [)art, 

 young or old whicii contains any caffeine or theol)romine and as no 

 [)arts have become detached, tiiis fact can oidy be explained by 

 assuming that these xanthine derivatives have again entered into the 

 internal mutation. 



With the Thea species the matter appears quite different ; tlie 

 young leaves and also the full grown ones are rich in caffeine and 

 the quantity found in the bark is a mere nothing as compared with 

 that contained in the leaves. Here it would appear as if, with the 

 falling of the leaves, the caffeine as such would be lost ; this view, 

 however, is not correct. 



On testing tea leaves which had tni-ned yellow and would fall 

 at the merest touch, it appeared that Ihej^ were quite caffcinc-free 

 both in the case of Thea assamica and T. sinensis. The same was 

 noticed with Coffea liberica and Theobroma Cacao (also in regard 

 to theobromine) that is to say hi the case of all species whose full 

 grown leaves still contained xanthine derivatives, with the exception 

 of Coffea arabica. During our stay at Bnitenzorg it was, however, 

 not possible to obtain leaves which had fallen after having turned 

 yellow in tlie normal manner. All the leaves iiad been attacked by 

 Hemileia vadatriv which causes a [)rematurc turning yellow and 

 falling. It is probably due to this fad that no caffeine-free yellow 

 lea\'es \vere met with. 



We, therefore, see that these xanthine derivatives disappear from 

 the leaves shortly before they fall, whilst the bark of the older 

 branches bearing these leaves is either free from these substances 

 (and reuiains so as in the case of Theobroma (^acao and Cotfea 

 liberica) or contains such a trilling quantity thereof that it is as 

 nothing couqiared with the cpjantily disappeared from the leaves, as 

 in the case of Thea sp. 



If we now take into consideration that the leaves of the brandies 

 which are quite devoid of young shoots or flowers also show tlie 

 same behaviour, we can stale with cerlaiuty thai the xanthine deri- 

 vatives agai]i enter into the internal mutation and are, therefore, at 

 least in this case, an bitermeduwij and not a piuil product. This 



