CARBONATE OF SODA. 437 



alkaline carbonates exist in the blood. Alkaline carbonates were 

 always found in the ash of blood, (as for instance, by Berzelius, 

 Marcet, Mitscherlich, Tiedemann and Gmelin, and more recently 

 by Nasse, Marchand, and others,) till Enderlin* announced that 

 blood incinerated according to his method, left an ash which did 

 not yield a trace of carbonic acid. He examined the ash of the 

 blood of men, oxen, sheep, and hares, and found that in addition 

 to the ordinary chlorides and sulphates, the soluble salts consisted 

 solely of tribasic phosphate of soda. Hence he concludes that as 

 no carbonates can be found in the ash, it is altogether impossible 

 that any carbonated alkali can occur in the blood. But it does 

 not follow that the earlier observers were in error, when they 

 found carbonate of soda in the blood, (Nassef? for instance, found 

 from 0'06 to 0'08, and Marchandt, 0'125--,) for we can at pleasure 

 prepare a blood-ash either with or without carbonates, according 

 to the degree of heat and the method of incineration we employ. 

 If we heat common phosphate of soda (2NaO . HO . PO 5 ) with 

 carbonate of soda, the latter loses its carbonic acid, and as a 

 necessary consequence there is formed the tribasic phosphate of 

 soda ; when dissolved in water, this tribasic phosphate of soda very 

 rapidly absorbs carbonic acid from the atmosphere, and becomes 

 converted into carbonate and c (common) phosphate of soda. 

 Hence tribasic phosphate of soda cannot exist in the circulating 

 blood, since this fluid contains sufficient carbonic acid to ensure 

 its decomposition. 



Assuming that carbonate of soda exists in the blood-ash, this 

 by no means proves that it is present in fresh blood, for this fluid 

 contains fatty and other organic acids in combination with alkalies, 

 which on incineration are converted into carbonates. But if we 

 consider that fresh blood always has an alkaline reaction, and that, 

 in consequence of its always containing carbonic acid, caustic soda 

 can no more occur in it than the above-mentioned tribasic phos- 

 phate of soda, this reaction can hardly be attributed to any other 

 body than to carbonate of soda; for the combinations of the fatty 

 acids with alkalies are contained in the blood in far too small 

 quantities to account for the alkaline reaction of that fluid, and 

 the amount of carbonate present in the ash. Liebig was the first 



* Ann. d. Ch. u. Pharm. Bd. 50, S. 53. 



t Handworterb. der Physiolog. Bd. 1, S. 167. 



I Lehrb. d. physiol. Chem. S. 226. 



Ilandwbrterb. der Chem. Bd. 1, S. 001. 



