152 ON ANIMAL AND 



latter, from that spirit of investigation which 

 urged him to discover new substances for the 

 gratification of his taste or his appetite, in the 

 prosecution of which, he would naturally give 

 trial to such as were deleterious in their nature, 

 in common with those that were wholesome and 

 useful. Having thus far succeeded, he would 

 still be exposed to accidents, from mistaking one 

 substance for another, in those instances, where 

 the external character of vegetables bore so near 

 a resemblance, as not to admit of an easy dis- 

 crimination. 



Of mineral poisons he could know but little; 

 as the various metals and their chemical changes 

 by which a poisonous quality is imparted, wer& 

 then only very partially understood ; and the 

 earths, the alkalies, and the acids (most of which, 

 excepting in very limited proportions are inimical 

 to the human frame), from being at that time but 

 little used, were still further removed from his 

 knowledge, 



The more we become acquainted with those 

 substances which have been denominated poisons, 

 the more are we convinced (when properly ap- 

 plied), of their utility, either in the arts, in medi- 

 cine, or in some instances as articles of food, of 

 which I shall offer some practical illustrations 

 when I come to treat on particular poisons ; and 

 although those from venomous animals, may, in 

 some instances, be an exception to these obser- 



