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CHAPTER IX. 



MISCELLANEOUS EXAMPLES OF THE FOUR 

 METHODS. 



1. I SHALL select, as my first example, an 

 interesting speculation of one of the most eminent 

 theoretical chemists of the present or any age, Dr. 

 Liebig. The object in view, is to ascertain the imme- 

 diate cause of the death produced by metallic poisons. 



Arsenious acid, and the salts of lead, bismuth, 

 copper, and mercury, if introduced into the animal 

 organism, except in the smallest doses, destroy life. 

 These facts have long been known, as insulated 

 truths of the lowest order of generalization ; but it 

 was reserved for Liebig, by an apt employment of the 

 first two of our methods of experimental inquiry, to 

 connect these truths together by a higher induction, 

 pointing out what property, common to all these 

 deleterious substances, is the really operating cause of 

 their fatal effect. 



When solutions of these substances are placed in 

 sufficiently close contact with many animal products, 

 albumen, milk, muscular fibre, and animal mem- 

 branes, the acid or salt leaves the water in which it 

 was dissolved, and enters into combination with the 

 animal substance ; which substance, after being thus 

 acted upon, is found to have lost its tendency to spon- 

 taneous decomposition, or putrefaction. 



Observation also shows, in cases where death has 

 been produced by these poisons, that the parts of the 

 body with which the poisonous substances have been 

 brought into contact, do not afterwards putrefy. 



