ON THE LEAVES OF CATHA EDULIS. 169 



XVI. On the Leaves of Catha edulis. 

 By C. Schorlemmer, F.R.S. 



Eead October 16th, 1883. 



In a paper which I read before the Society a few months 

 ago, I stated that the custom of drinking coffee was intro- 

 duced into Arabia only in the beginning of the fifteenth 

 century. Before this time the beverage made of leaves 

 of kat [Catha edulis) was used, and is still in use, pos- 

 sessing properties resembling those of strong green tea, 

 only more pleasing and agreeable. From this it appeared 

 to me highly probable that kat contained caffeine, which 

 occurs in tea, coffee, and some other plants, all of which 

 are used as stimulants. 



Professor T. Thiselton Dyer, F.R.S., kindly supplied me 

 with fresh leaves of Catha, grown in Kcw Gardens. Not 

 a trace of caffeine was found, while, to show its presence 

 in tea, a very few leaves are sufficient. 



From the facts it appeared probable that the tea and 

 coffee grown at Kew would not contain it ; that, however, 

 was found not to be the case. Its presence could be 

 easily detected in the leaves of Thea viridis and Coffea 

 arabica. 



Through the kindness of Professor Dyer I have since 

 obtained two genuine samples of kat, coming directly 

 from Aden, one being labelled " Kat Sabari/-* so called as 

 coming from Sabar, a mountain-range in Yemen, and the 

 other " Kat Mactari Ashab," as it has long (ashab) leaves. 

 I have examined both carefully without finding a trace of 

 caffeine or an alkaloid related to it. It requires, there- 

 fore., further researches in order to discover the active 

 principle of Catha. 



SEE. III. VOL. VIII. N 



