■with an Account of some curious Properties of that Substance. 113 



some modification, probably in its state of aggregation, diffi- 

 cult to unravel. If the precipitated albumen is merely digested 

 in an aqueous solution of carbonic acid in a closed flask for 

 some hours, as much appears to be taken up as if a airrent of 

 the gas was used; and hence 1 have been led to conclude that 

 the solubility of the albumen is not so much owing to the for- 

 mation of a definite soluble compound (carbonate?) as to its 

 being merely dissolved in the quantity of acid gas which water 

 is capable of holding in solution at ordinary atmospherical 

 pressure and temperature. 



5. The solution of albumen in carbonic acid behaves to re- 

 agents like a mere aqueous solution, — as dilute serum of blood, 

 with, as far as I know, a single exception, and this is the action 

 of very dilute ammonia, which produces a precipitate of albu- 

 men soluble in an excess of the alkali. Heat produces a de- 

 posit of albumen with a simultaneous evolution of carbonic 

 acid gas; nitric acid, tincture of galls, acidulated ferrocyanate 

 of potassa, and bichloride of mercury all produce copious pre- 

 cipitates. By exposure to the air it does not very I'eariily be- 

 come turbid, the carbonic acid being very slowly evolved : 

 after the lapse of a week, however, the albumen is deposited 

 in a white impalpable form. The presence of carbonic acid 

 in these solutions of albumen appears to prevent its ready 

 precipitation by nitric acid, several drops being required to 

 produce a considerable troubling; and on this account I am 

 accustomed to use the nitrohydrochloric acid as a preferable 

 precipitant when I have the detection of albumen in an animal 

 fluid in view, as the action of this acid does not appear to be 

 so liable to be affected by carbonic acid. 



6. Wishing to ascertain with greater accuracy whether the 

 albumen precipitated from its solution in soda by carbonic 

 acid, depended for its resolution upon the formation of a com- 

 pound with that acid, or upon the solvent action of the bicar- 

 bonate necessarily formed, I availed myself of Dr. Stevens's 

 adaptation of Prof. Graham's law of the difl"usion of gases, by 

 placing a glass vessel filled with the solution (3.) under a 

 large receiver full of hydrogen gas inverted over water. In 

 twelve hours the apparatus was examined, and the fluid sub- 

 jected to experiment, previously quite limpid, was found to be 

 very turbid from the deposition of its albumen ; the carbonic 

 acid having been abstracted by the hydrogen gas. A modi- 

 fication of this experiment was then made by placing over the 

 fluid subjected to tiie hydrogen gas, a capsule (illed with 

 lime-water : the cai bonic acid being abstracteil as before, was 

 uUioi bed by the lime-water, causing the precipitation ol car- 



ThirU Sencs. Vol, 9. No. 52. Aui2. IbLiG. O 



