200 ZOOLOGY. [PART IT. 



Africa, who lay hold of the Cerastes without fear or 

 hesitation, their impunity is ascribed to the use of a 

 plant with which they anoint themselves before touching 

 the reptile 1 ; and Bruce says of the people of Sennar, 

 that they acquire exemption from the fatal consequences 

 of the bite by chewing a particular root, and washing 

 themselves with an infusion of certain plants. He adds 

 that a portion of this root was given him, with a view to 

 test its efficacy in his own person, but that he had not 

 sufficient resolution to undergo the experiment. 



As to the snake-stone itself, I submitted one, the ap- 

 plication of which I have been describing, to Mr. 

 Faraday, who has communicated to me, as the result 

 of his analysis, his belief that it is " a piece of charred 

 bone which has been filled with blood perhaps several 

 times, and then carefully charred again. Evidence of 

 this is afforded, as well by the apertures of cells or tubes 

 on its surface as by the fact that it yields and breaks 

 under pressure, and exhibits an organic structure within. 

 When heated slightly, water rises from it, and also a 

 little ammonia ; and, if heated still more highly in the 

 air, carbon burns away, and a bulky white ash is left, 

 retaining the shape and size of the stone." This ash, 

 as is evident from inspection, cannot have belonged to 

 any vegetable substance, for it is almost entirely composed 

 of phosphate of lime. Mr. Faraday adds that " if the 

 piece of matter has ever been employed as a spongy 

 absorbent, it seems hardly fit for that purpose in its 

 present state ; but who can say to what treatment it has 

 been subjected since it was fit for use, or to what treat- 

 ment the natives may submit it when expecting to have 

 occasion to use it ? " 



The probability is, that the animal charcoal, when 

 instantaneously applied, may be sufficiently porous 

 and absorbent to extract the venom from the recent 

 wound, together with a portion of the blood, before it 

 has had time to be carried into the system ; and that the 



1 ITassellquist, 



