132 Transactions of the South African Philosophical Society. 



was identified as belonging to the genus Polygonum, probably 

 Polygonum tomentosum, var. glabrum. The plant is stated to be 

 used by the natives as a remedy for black gall-sickness. From the 

 plant, by means of alcohol, an acrid resin was extracted, which yielded 

 the following colour reactions with strong sulphuric acid : bright 

 pink to cherry-red colour, changing gradually through a deep lake 

 to a dirty brown, and ultimately fading to a greenish tint. Doses of 

 extract from the powdered plant were administered to three mice 

 with the following results : — 



Quantity of Plant Period within which 



represented by dose. death occurred. 



Three-fifths of a grain Four hours. 



Three-fourths of a grain Two hours . 



Four-fifths of a grain , One hour. 



In each case the symptoms were very similar : uneasiness within 

 10 minutes, breathing at first very rapid but soon succeeded by 

 pronounced intermittence of respiration, gaping and straining as if 

 preparatory to emesis ; the resin appeared to act as a strong 

 depressant. After death the hearts were found to be pale ; in two 

 cases the left ventricle was firmly contracted, whereas in the third 

 the right ventricle was contracted and contained very little blood ; 

 the stomachs and intestines were distended. A quantity of infusion 

 equivalent to 8 grains of the powdered plant was given to a dog 

 without any noticeable effect being produced. 



Through insufficiency of material no further experiments could be 

 carried out, but it appeared probable that the resin, present to the 

 extent of nearly 2 j- per cent, in the dried root, was the active principle 

 that caused the fatality. It appeared likely that when given in toxic 

 doses the drug would eventually paralyse the heart muscle and arrest 

 that organ in systole. 



I have alluded to some of the practical difficulties occurring in 

 connection with investigations of the class that forms the subject of 

 these notes ; in addition to these, other circumstances are constantly 

 coming to light which show that much more care and discrimination 

 require to be exercised in selecting and submitting for analysis 

 samples connected with matters of such grave importance. Bottles 

 are so badly packed and sealed that loss, total or partial, of liquid 

 contents, in transmission, is not infrequent ; besides this, articles are 

 often sent for analysis at haphazard, without circumspection, and 

 very carelessly dealt with. In one case of alleged attempted poison- 

 ing it was asserted that snake-poison had been employed as the 

 agent : in proof hereof a dead snake, said to have been found near 



