192 Comparative Examination of the Mucous Acid 



loured mass, which I redissolved in water in order to ob- 

 tain whiter and purer crystals. 



The mother waters of this second portion of mucous 

 acid and of oxalic acid, contained a mixture of oxalic and 

 malic acids, which I separated from each other, by means 

 which I shall not detail, because they would lead me away 

 from the principal object of my experiments, 



The first portion of mucous acid which I obtained 

 weighed nine grammes and a half, it was very white; when 

 dried it had the grumous appearance of starch. This was 

 the substance which I employed in my experiments. I re- 

 jected the second portion, because it did not seem to be of 

 the same purity. 



With the view of ascertaining the presence of the oxalate 

 of lime in this mucous acid, T mixed one part of the nitric 

 acid as above, with ten parts of distilled water, and poured 

 this mixture upon the nine grammes and a half of mucous 

 acid. I exposed the whole to a heat of 40 or 50 degrees 

 during twice 24 hours, taking care to stir it from time to 

 time, to facilitate the action of the solvent. I decanted the 

 supernatant liquor, in which ammonia immediately pro- 

 duced the precipitation of a white earthy salt,' in silky fila- 

 ments, which had all the physical properties of the cal- 

 careous oxalate. 



A second portion of weak nitric acid, added to the sedi- 

 ment of the foregoing liquor, and left to itself during the 

 same time, furnished with ammonia a new quantity of 

 oxalate of lime. 



It required eight portions of weak nitric acid, successively 

 added, to clear entirely from oxalate of lime the mucous 

 acid submitted to the experiment. Every time the am- 

 monia, when mixed with the decanted and filtered liquor, 

 separated from it a quantity of calcareous oxalate, the pro- 

 portion of which diminished at each digestion in a striking 

 manner. The ninth portion exhibited but very minute 

 traces of it. 



The eight precipitates united together gave a total weight 

 of two grammes three decigrammes. 



It was important to ascertain, if this substance, which 

 was foreign to the mucous acid, and whose appearance and 

 physical characters appeared to me to be similar to those 

 of the oxalate of lime, was really this calcareous salt. 



With this view I boiled this substance, with a saturated 

 solution of carbonate of potash ; and when the reciprocal 

 decomposition of the two salts seemed to me to be com- 

 pleted, I collected on a filter the portion which was de- 

 posited, 



