ALL THINGS USEFUL. 95 



in contact with it ; and others, again, offend, and 

 even waste and wear our organs of sense. But it 

 is our own fault, if we allow them to produce any 

 of these bad effects. We need not swallow arsenic, 

 be bitten by rattlesnakes, offended by the sight of 

 toads or neuts, or sickened by noxious effluvia. 

 We should find out their properties, and shun those 

 that are hurtful, at the same time that we turn to 

 advantage those that are beneficial. Deadly as the 

 white oxide of arsenic is when taken into the hu- 

 man stomach, arsenic, used for proper purposes, is 

 a highly valuable substance. Some of its oxides 

 are beautiful paints, others give purity to glass, 

 hardness to the metal of printing types and the 

 mirrors of telescopes ; and even the deadly poison 

 itself is the most effectual remedy in some diseases. 

 Prussic acid, again, which in certain states is a 

 more deadly poison, perhaps, than even arsenic, is 

 not only in other states a valuable medicine, as 

 well as a most essential ingredient in some of the 

 most grateful tastes and odours, but it is highly 

 probable that it tends as much, and perhaps more 

 than any other substance in nature, to produce the 

 colours of those flowers which render the fields and 

 the gardens so gay. These are, no doubt, extreme 

 cases ; but they are cases to the purpose ; and 

 with them before us, we must learn not to have an 

 aversion to, or to despise, any one of nature's pro- 

 ductions, until we can be sure that we know all its 

 properties and all the purposes that it will answer. 

 And as that is a degree of knowledge at which we 

 never can arrive, it is tantamount to saying, that 

 we should never despise, or cease further to exa- 

 mine, any natural object whatsoever; because, even 

 in the most common and neglected one, there may 



