TROPICAL AGRICULTURE 



ALOES 



Aloes is a plant belonging to the lily family, native of India 

 and Africa, but also cultivated in the West Indies for the drug 

 and elsewhere as an ornamental. Aloe perryi yields Socotrine 

 aloes, has white spines on the leaves, and spikes of orange-red 

 flowers. A. vera, yields the Barbados aloes, has yellow leaf 

 spines, and yellow flowers. A. spicata of Africa yields the 

 drug known in trade as Cape aloes and has white flowers. The 

 plants resemble agaves, or century plants in habit of 

 growth. 



The drug is the dried juice of the leaves which are cut into 

 sections, after which the juice is allowed to run out and is 

 then concentrated by boiling, or is allowed to dry sponta- 

 neously. Socotrine aloes is yellowish and brings the highest 

 price. Zanzibar aloes is a dark brown variety of Socotrine 

 aloes. Both the Curasao and Barbados aloes come from the 

 Dutch West Indies. In fact, the main supply of aloes is now 

 obtained from Curagao. Aloes is used in both human and vet- 

 erinary medicine as a cathartic. 



CALABAR BEAN 



This is a woody leguminous climber (Physostigma veneno- 

 sum), native of Africa. It bears violet-colored flowers and a 

 flattened, pointed pod containing 2 or 3 seeds or beans. Sev- 

 eral alkaloids are obtained from the ripe beans, but the most 

 important is eserine or physostigmine. Eserin is one of the 

 most powerful alkaloids and has the specific effect of greatly 

 stimulating the involuntary musculature of the intestines and 

 blood vessels. The Calabar beans yield about 0.25 per cent, of 

 eserine. The plant attains a length of 30 to 50 feet and be- 

 comes almost shrubby at the base. The beans are for the most 

 part collected from wild vines since thus far the plant has not 

 beea extensively cultivated. 



