OF SERPENTS. 11^ 



rature. After them comes mercury, and after it, the 

 imperfe£t and femi-metals : thefe laft, of which arfenic 

 is one, for the moft part attra6t oxygen ftrongly, and 

 are generally found united with it under various forms 

 in the bowels of the earth.* 



Oxygen, we have already obferved, is a principle 

 which enters into the compofition of the blood, and 

 performs a very important part in the animal oecono- 

 my. It muft alfo be evident that the blood may be 

 more or lefs loaded with this principle, and that difeafe 

 may be produced, either by too great, or by too fmall 

 a quantity being prefent in the circulating mafs. We 

 have already faid that the difeafe produced by the 

 bite of a ferpent, arifes from the fubtra6i:ion of oxygen 

 from the blood ; the indication of cure muft therefore 

 be, to fupply this oxygen, which we fuppofe to be 

 withdrawn. The moft obvious method of accomplifli- 

 ing this will be to employ fuch fubftances as are known 

 to contain oxygen in the greateft abundance, and to 

 part with it with the greateft facility. This is pre- 

 cifely the chara61:er of the lunar cauftic, which is made 

 by dilfolving filver in the nitric acid, and afterwards 

 evaporating and criftallifmg the folution. The com- 

 pofition of the nitric acid is alfo accurately afcertained, 

 it differs from the common nitrous acid of the fliops, 

 by containing a greater quantity of oxygen, and in a 

 fmgularly loofe form ; fo that if our reafoning upon 

 the poifon of the ferpent be in any degree correal, no 

 medicine w^ould appear to be better calculated than 

 this, to obviate its effects. 



The application of the foregoing principles, will 

 explain the probable efficacy of the different metallic 

 preparations we have juft fpoken of, which will be 



* I am very fenfible that the terms perfeft, imperfeft, and femi- 

 metals, are improper: for all metals are equally perfect of their kind, 

 but I have complied with the common terms, that I might the more 

 readily be underftood. 



H 2 conne6ted 



