676 FHILOSOPHICAL TRANSACTICWS. [annO 1775. 



moment that it was the same as what had been brought to me from the myrrh 

 country ; but I had the additional satisfaction to find the tree all covered over 

 with beautiful crimson flowers, of a very extraordinary and strange construction. 

 I began then a drawing anew, with all that satisfaction known only to those who 

 have been conversant in such discoveries. I took pieces of the gum with me. 

 It is very light. Galen complains that, in his time, the myrrh was often mixed 

 with a drug which he calls opocalpasum, by a Greek name ; but what this drug 

 was, is totally unknown to us at this day. But as the only view of the savage, 

 in mixing another gum with his myrrh, must have been to increase the quantity; 

 and as the great plenty in which this gum is produced, and its colour makes it 

 very proper for this use ; and above all, as there is no reason to think there is 

 another gum-bearing tree, of equal qualities, in the country where the myrrh 

 grows, it seems to me next to a proof, that this must have been the 

 opocalpasum. 



I must however confess, that Galen says the opocalpasum was so far from an 

 innocent drug, that it was a mortal poison, and had produced very fatal effects. 

 But as those Troglodytes, though now more ignorant than formerly, are still 

 well acquainted with the properties of their herbs and trees, it is not possible 

 that the savage, desiring to increase his sales, would mix them with a poison 

 that must needs diminish them. And we may therefore without scruple sup- 

 pose, that Galen was mistaken in the quality ascribed to this drug ; and that he 

 might have imagined that people died of the opocalpasum, who perhaps really 

 died of the physician. First, because we know of no gum or resin that is a 

 mortal poison : 2dly, because, from the construction of its parts, gum is very 

 ill adapted for having the activity which violent poison has ; and considering the 

 small quantities in which myrrh is taken, and the opocalpasum could have been 

 but in an inconsiderable proportion to the myrrh, to have killed, it must have 

 been a very active poison : 3dly, these accidents, from a known cause, must 

 have brought myrrh into disuse, as certainly as the Spaniards mixing arsenic 

 with the bark, would banish that drug when we saw people die of it. Now this 

 never was the case : it maintained its character among the Greeks and the Arabs, 

 and so down to our days ; and a modern physician thinks it might make man im- 

 mortal, if it could be rendered perfectly soluble in the human body. 



Galen then was mistaken as to the poisonous quality of the opocalpasum. 

 The Greek physicians knew little of the natural history of Arabia ; still less of 

 that of Abyssinia ; and we who have followed them know nothing of either. 

 This gum, being put into water, swells and turns white, and loses all its glue : 

 it resembles gum adragant much in quality, and may be eaten safely. This 

 specimen came from the Troglodyte country in the year 177 i "• a piece of myrrh 

 from Arabia Felix, and a piece of gum of the sassa from Abyssinia, were packed 



