SOURCE OF THE ACIDITY OF THE GASTRIC JUICE. 247 



1843 and the other in 1851, in a third, Blondlot regards the 

 presence of this principle in the gastric juice as conclusively 

 established by the fact that it forms a precipitate of the neu- 

 tral phosphate of lime with pure lime-water ; the precipitate, 

 as he assumes, being formed by the neutralization of the acid 

 phosphate. 1 This conclusion is undoubtedly perfectly legit- 

 imate ; and there can be no doubt but that the biphosphate 

 of lime always exists in the gastric juice, in greater or less 

 quantity. This principle must be put in the place of the neu- 

 tral phosphate, which is given by most authors, for the latter 

 salt cannot exist in a fluid containing free hydrochloric or lac- 

 tic acid, either of which acids would immediately appropriate 

 the excess of the base. That a free acid exists in the gastric 

 juice in a proportion more than sufficient to simply act upon 

 the neutral phosphates which would then form lactates and 

 leave the biphosphate as the single acid principle is shown 

 by the fact that the gastric juice will dissolve and act 

 upon an excess of the neutral phosphate of lime. 2 This 

 fact in itself is sufficient to show that the gastric juice does 

 not depend for its acidity entirely on the biphosphate of 

 lime. 



There can be no doubt of the constant presence of the 

 acid phosphate of lime in the gastric juice, at least in the 

 dog ; and its quantity is undoubtedly increased in this ani- 

 mal during the digestion of bones, by the action of the acid 

 fluid upon their phosphatic constituents ; but the arguments 

 of Blondlot against the existence of a free acid have little or 

 no weight. One of those on which most stress is laid is that 

 the gastric juice does not act upon the carbonates; which 



1 Loc. cit., p. 309. 



2 BERNARD, VILLEFRANCHE ET BARRESWIL, Sur les Pkenomenea Chimiques de 

 la Digestion (deuxieme memoire). Comptes Rendus, Paris, 1844, tome xix., p. 

 1284. These authors state that the gastric juice will dissolve the neutral phos- 

 phate of lime, which is insoluble in the biphosphate (p. 1285); but this is not, as 

 they supposed, an argument against the existence of the biphosphate, for it has 

 long been well known that the neutral phosphate of lime is readily dissolved in 

 acid liquids. 



