'which dissolves the adjacent parts, and at last, 

 -when its situation allows it, empties itself through 

 the skin. Many chemical experiments have been 

 made with this pus; the object of which, how- 

 ever, has only been to learn to distinguish it in 

 diseases of the lungs from the expectorated mu- 

 cus, that physicians might be able the better to 

 judge of the nature of the disease; but, notwith- 

 standing all these experiments, we have not at- 

 tained any satisfactory results ; however, the mu- 

 cus in the trachea aud bronchia has chemical 

 characters very distinct from those of pus, since 

 the former is very easily dissolved by acids, and 

 remains thus dissolved, and the latter requires 

 the acids to be more concentrated, and may, af- 

 ter the solution, again be* precipitated by water* 

 The reason why the methods of examination, pro- 

 posed by DARWIN, BRUGGMANS, GRASMEYER 

 and others, have had no certain results, is this, 

 that no correct distinction has been made be- 

 tween mucus and pus. They always considered 

 as mucus, the yellow matter, which is expecto- 

 rated after the crisis of the inflammation in the 

 lungs, and where no destruction of parts had oc- 

 curred. On the other hand, they considered that 

 only as pus, which is generated in an abscess or 

 in an open suppurating ulcer in the lungs* This 



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