438 SECOND CLASS OF MINERAL CONSTITUENTS. 



to remark that the carbonate of soda must be contained in the 

 blood as a bicarbonate. No free acid can be present with common 

 carbonate of soda. The following experiment favours the view of 

 the presence of the bicarbonate : if we precipitate the serum of the 

 blood with alcohol and thoroughly wash the precipitate with 

 dilute spirit, the albumen on incineration leaves no alkaline ash ; if 

 soda were chemically combined with album en, the soda must be 

 precipitated with the albumen, while neutral carbonate of soda and 

 especially the bicarbonate dissolve readily in spirit. On passing 

 hydrogen through the fluid from which the albumen has been 

 removed by nitration, carbonic acid is expelled ; for as Magnus 

 and Rose formerly proved, and as Marchand* has recently again 

 demonstrated, hydrogen completely expels the one atom of car- 

 bonic acid from the bicarbonate of soda, especially if the tempera- 

 ture be raised to 38. Liebig also adduces the relation of corrosive 

 sublimate to the fluid freed from the albumen by spirit of wine, in 

 evidence of the presence of bicarbonate of soda ; for, on the addi- 

 tion of corrosive sublimate to this fluid, there is no precipitate, 

 but after some time there are deposited brown crystals of oxy- 

 chloride of mercury, precisely as would have occurred if this reagent 

 had been added to a solution of bicarbonate of soda. By means of 

 a current of pure hydrogen gas, and by the repeated application of 

 the air-pump, I so thoroughly removed the carbonic acid from 

 freshly whipped ox-blood, that a fresh stream of hydrogen passed 

 through the blood no longer produced the slightest turbidity in 

 baryta-water ; by means of a special contrivance, so as to exclude 

 the access of the air, a little acetic acid was forced into the blood 

 by means of the hydrogen gas, and the latter was again passed in 

 considerable quantity through the blood; immediately after the 

 addition of the acetic acid to the blood the baryta-water was ren- 

 dered turbid by the current of hydrogen. We thus obtain a proof 

 that a certain quantity of the carbonic acid in the blood exists in 

 combination with a base, in addition to that which can be expelled 

 by gases and extracted by the air-pump. Hence there can no 

 longer be any doubt regarding the presence of carbonate of soda 

 in the blood. I have found, taking the mean of ten carefully 

 conducted quantitative analyses,f that ox-blood contains 0*1628$ of 

 ordinary carbonate of soda, after the expulsion of the free carbonic 

 acid in the manner which has already been described. 



* Journ. f. pr. Chem. Bd. 35. S, 390. 



t Ber. d. k. sachs. Ges. d. Wiss. 1847, S. 96-100. 



