tioith an Accoimt of some curiotis Properties of that Substance. Ill 



cyanate of potash (after the addition of acetic acid), and tinc- 

 ture of galls ; reactions quite characteristic of solutions of al- 

 kaline albuminates, 



3. A solution of albuminate of soda (2.) was diluted con- 

 siderably with cold distilled water and placed in a tall cylindri- 

 cal glass vessel ; through this fluid a current of carbonic acid 

 gas was passed, the tube from which the gas issued being suffi- 

 ciently long to reach the bottom of the vessel : in a few minutes 

 the fluid, before transparent, became opake, and rapidly de- 

 posited a copious precipitate of albumen in the state of a beau- 

 tifully white, impalpable powder ; the acid gas being allowed 

 to pass for some time longer, the precipitate gradually disap- 

 peared until the whole was as limpid as before the experiment. 

 The solution thus obtained was acid, and consequently red- 

 dened litmus-paper, whereas before the experiment it red- 

 dened turmeric ; it afforded a copious deposit with those re- 

 agents which precipitate solutions of albumen in mere water, 

 or when dissolved by acids, but not with those which affect 

 solutions of albumen in the alkalies only: thus, ebullition 

 caused a considerable deposit, as also did nitric acid, tincture 

 of galls, bichloride of mercury, and alum ; whereas the dilute 

 acidsand perchloride of iron did not disturb the limpidity of the 

 fluid, although, as before stated, prior to the passage of the 

 acid gas they produced copious precipitates. Heat, I have 

 already stated, caused a considerable deposit of albumen in the 

 same manner as from a mere aqueous solution of albumen 

 which had not undergone coagulation, but differed in requir- 

 ing a higher temperature, a full boiling-heat being necessary 

 to produce a considerable precipitate. Ammonia when very 

 dilute caused a precipitate also, which readily dissolved in an 

 excess of the precipitant ; the action of heat was of course ac- 

 companied with a copious evolution of carbonic acid gas. 

 From these facts I was induced to conclude that the albumen 

 previously existing in combination with the soda, had left that 

 alkali to combine with the carbonic acid, thus playing the part 

 of a base or electro-positive element, leaving the soda in the 

 state of bicarbonate, that salt being of course formed by the 

 action of the carbonic acid added : the solution might thus be 

 supposed to contain a mixture of the carbonates of soda and 

 albumen with an excess of carbonic acid. To this explanation 

 it might be objected, that as alkaline bicarbonates are known 

 to dissolve albumen, the acid gas had only converted the 

 alkali into a bicarbonate, which tluis held the albumen in solu- 

 tion : if this were true, Iiow can the precipitation of albumen 

 on the first passage of the gas be explained, unless it be sup- 

 posed that the neutral alkaline carbonate which is first formed, 



