Dr. Pearson on expectorated Matter. ggg 
by the first digestion in the same menstruum, in containing a 
much smaller proportion of potash and muriate of soda, as 
well as of neutralized ammonia. 
6 . The extract-like matter, from the third digestion in 
vinegar (2 c), differed from the former, in containing a still 
much less quantity of the salts just mentioned. 
7. The fourth and subsequent digestions (2, d, e ) afforded 
extract-like substances, which contained scarcely any thing 
but a very small proportion of earthy phosphates, and indis- 
soluble vitrified matter, produced by incineration and fusion. 
It did not appear that the oxide of animal matter, dissolved by 
the distilled vinegar in all the preceding digestions successive- 
ly, was of different kinds ; but it appeared, that its coagulable 
property was destroyed by dissolution in this menstruum. 
Accordingly, there is no reason to believe that the whole of 
this oxide is not dissoluble in the acid here employed, al- 
though the requisite proportion may decrease after each 
digestion, within certain limits. 
8. A few drops of opaque ropy matter being agitated in 
half a pint of vinegar, a number of fibrous masses appear, 
apparently one fourth or one fifth the bulk of the matter 
added ; and these fibrous forms subsist, notwithstanding con- 
tinued agitation, totally disappearing only in consequence of 
long digestion in. successive large quantities of this acid. 
§ VI. Some Experiments with different Objects. 
1. To produce a synthetic proof that potash may be neu- 
tralized by oxide of animal matter, I triturated ten grains of 
the exsiccated and coagulated part of expectorated matter freed 
from all saline substance, with pure potash gradually added, 
