112 Mr. G. Bird on certain new Combinations of Albumen, 



is incapable of holding in solution so large a quantity of al- 

 bumen as the free alkali, or its bicarbonate ; an assumption 

 directly opposed to fact, as I shall have occasion to show in 

 another place : besides which, the action of reagents ought to 

 differ, and instead of those only which precipitate acid solu- 

 tions of albumen producing a turbidity, a troubling should be 

 produced by those also which affect its alkaline solution, for 

 surely the solution of an animal matter in a carbonated alkali 

 approaches less to the nature of an acid than to that of an al- 

 kaline solution. 



4. I next attempted to form a solution of albumen in car- 

 bonic acid, excluding the agency of alkali, which if successful 

 would, I considered, at once demonstrate the real nature of 

 the combination ; but in this I experienced considerable diffi- 

 culty, for when a current of carbonic acid gas was passed 

 through an aqueous solution of albumen (1.), no distinct com- 

 bination was obtained ; and on attempting in a similar manner 

 to dissolve albumen previously coagulated by the action of 

 heat or acids, I failed to obtain satisfactory results, from the 

 close state of aggregation in which the albumen was obtained 

 appearing to present a considerable resistance to the solvent 

 action of the acid. I at length succeeded by precipitating al- 

 bumen from serum of blood by means of alcohol, well wash- 

 ing the precipitate until all traces of alcohol were removed, 

 (the vessel in which the precipitation was performed being 

 immersed in ice-cold water to prevent the action of the evolved 

 heat on the albumen,) carefully avoiding any unnecessary ex- 

 posure to the air, which, by drying it, might serve to lessen 

 its solubihty in the acid. A portion of this finely divided al- 

 bumen was diffused through cold water, and submitted to the 

 action of a current of carbonic acid gas; after a short time it 

 entirely dissolved ; but the solution was not perfectly limpid, nor 

 did it become so by filtration. In preparing this solution care 

 must be taken to add a sufficient quantity of water, otherwise 

 a considerable quantity of albumen will be carried mechani- 

 cally out of the fluid by each bubble of gas, and being depo- 

 sited on the sides of the vessel, will dry rapidly, and on being 

 returned to the fluid will be found to have lost much of its 

 solubility in the acid ; and it is very remarkable how large a 

 quantity of albumen can (by this kind of inverted filtration) 

 be carried beyond the influence of the gas. The finely divided 

 albumen obtained by passing a limited quantity of carbonic 

 acid into albuminate of soda (2.), after well washing, may be 

 substituted for that precipitated by alcohol, although it must 

 be observed that it is not quite so readily soluble as that ob- 

 tained by the latter process, owing to its having undergone 



