NATURAL HISTORY OF SOUTH AFRICA 



is that it deposits its excrement in some special place 

 amongst the rocks, and in consequence a large 

 accumulation occurs in course of time. This 

 excrement becomes saturated with the urine, and 

 eventually forms into a sticky black mass, in appear- 

 ance like pitch, and is known as " Dassie Sweet." 

 This is collected by the natives and is extensively 

 used by them as a drug. Considerable numbers of 

 colonists also use this substance at times. It is 

 administered to them by native medicine-men, in 

 whose powers to cure disease many farmers and 

 others unfortunately have considerable faith. 



The active principle in this substance seems to 

 be saltpetre, for if allowed to remain exposed to the 

 atmosphere under suitable conditions, it will undergo 

 a chemical change, and pure nitre or saltpetre, viz. 

 nitrate of potassium, will be the result. 



In the Natal Government Museum at Pieter- 

 maritzburg there is a series of specimens illustra- 

 tive of the formation of nitre from the excreta of 

 the Rock Dassie. In Natal I have collected this 

 excrement in all stages, from the black pitchy mass 

 to the pure white nitre. Sometimes there will be an 

 accumulation of this excrement on sandstone rocks 

 overhanging a cave or rock shelter. The liquid por- 

 tion slowly soaks into the porous rock, and for years 

 after the solid portion of the excrement has dis- 

 appeared, a black sticky substance will slowly exude 

 from the lower surface of the rock which forms the 

 roof of the rock shelter or cave. This forms into 

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