344 SIR THOMAS R. FRASER AND MR ALISTER T. MACKENZIE ON 



having the chemical properties of a glucoside. In many of its colour reactions it 

 closely resembles the extract of S. hispidus, as these have been described by one 

 of us in a paper communicated to this Society.* It differs, however, in several 

 colour reactions. For example, in the case of the dry extract, strong sulphuric acid 

 produces a dark brown which slowly becomes violet; and dilute nitric acid a light 

 yellow, which remains unchanged when the temperature is raised to 130° F. In the 

 case of a 2 per cent, solution in water, phosphomolybdic acid causes an abundant 

 yellow precipitate, which is dissolved by heating, and the solution on cooling becomes 

 dark blue in colour with a greyish deposit ; and the solution of the extract is made 

 bright yellow by the addition of molybdate of ammonium. 



Arrow-poisons. — In common with the seeds of several other species of Strophanthus, 

 those of S. sarmentosus are employed in producing an arrow-poison, which is in 

 extensive use in the districts of Africa where the plant occurs. Dr Dalziel has placed 

 at our disposal specimens of this arrow-poison, the preparation of which he has had an 

 opportunity of witnessing at Kantagora and at Zungeru, in Northern Nigeria. Accord- 

 ing to Dr Dalziel, the natives place about a quarter of a pound of coarsely ground 

 S. sarmentosus t seeds in an iron pot with about two pints of water and, after 

 heating to the boiling point, add a small quantity of a mixed powder containing 

 five ingredients, chiefly the bark and roots of several other plants. After boiling for 

 a few minutes, the contents of the pot are percolated through a rough filter of twigs, 

 leaves and husks, and the pea-soup-like percolate is again boiled until it has acquired 

 the consistence of a thin syrup. At Kantagora, the powdered head of a small venom- 

 ous serpent and a few drops of cock's blood are also added to the poison. The arrow- 

 heads are poisoned by being several times dipped into this syrupy liquid, and at 

 Zungeru they are finally dipped into some " animal substance." It is stated that 

 a poisoned arrow-head may be used several times without renewal of the poison. The 

 poison is a brownish-grey, grumous fluid of thin syrupy consistence, and holding 

 minute, flaky, solid particles in suspension. After being at rest for several weeks, a 

 small quantity of a brown, clear liquid collects at the upper part, and a considerable 

 cohesive, grey sediment at the bottom. This sediment was found to be insoluble 

 in water. 



When the thoroughly mixed poison was dried, it became a dark brown, brittle and 

 slightly hygroscopic solid, 10 c.c. of the original poison yielding 10'14 grams of solid 

 substance. When this dried poison was tested with the reagents giving fairly 

 distinctive colour-changes with the extract of S. sarmentosus seeds, no conclusive 

 results were obtained, no doubt because of the many ingredients, other than 

 Strophanthus extract, which are present in the arrow-poison. 



The poison in its original form, the liquid that spontaneously separates from it, and 

 the several times washed sediment were each tested in regard to lethality and effects 



* Trantactions of the Royal Society of Edinburgh, vol. xxxv., part iv., 1890, pp. 1001-3. 



t Some of these seeds were secured by Dr Dalziel, and on examination were found to be seeds of S. sarmentosus. 



