96 IS ACID OF GASTRIC JUICE FREE HYDROCHLORIC ACID ? [BOOK II. 



was due to acid sodium phosphate. " Dumas, Melsens and Bernard 

 have found that not only the carbonate, but also basic calcium phos- 

 phate is soluble in gastric juice, as also are even lead, zinc and iron, 

 hydrogen being simultaneously developed 1 ." 



Bernard and Barreswill 2 also maintained that the insolubility 

 of calcium oxalate in the gastric juice proved that it did not owe 

 its acidity to hydrochloric acid, inasmuch as a solution of hydrochloric 

 acid containing one part of the acid per mille dissolves the salt. 

 It has been shewn, however, that the organic matters of the gastric 

 juice must be the hindering cause, as when gastric juice is neutralized, 

 and then its natural acidity restored by the addition of hydrochloric 

 acid, the solution is incapable of dissolving C 2 O 4 Ca. 3 



Laborde 4 thought he had discovered an important point of differ- 

 ence between gastric juice and a dilute solution of hydrochloric 

 acid of corresponding acidity, by shewing, first, that such a dilute 

 solution of pure hydrochloric acid when treated with a solution of cane- 

 sugar, possesses a more powerful inverting action than the gastric 

 juice ; the inverting power of the latter corresponding to that of a 

 solution of lactic acid ; secondly, that when starch is heated with 

 a dilute solution of hydrochloric acid (containing only 0'25 of HC1 

 per mille) at 155 for two hours, it is entirely converted into dextrin 

 and grape-sugar, whilst with gastric juice under the same circum- 

 stances the conversion of starch is much less complete. 



Szabo 5 has subjected Laborde's facts to a searching investigation, 

 with the result of shewing that peptones interfere with the action 

 exerted by dilute hydrochloric acid upon starch ; in spite of this 

 interference, gastric juice has an action which is much more intense 

 than that of dilute lactic acid, and which is essentially the same as 

 that exerted by dilute hydrochloric acid. 



The Researches of Richet. 



An important series of researches has been performed by Richet 

 of late, which in the main confirm the researches of Schmidt, though 

 they have led the author to an hypothesis which is yet un- 

 proved. 



Richet, following in essential particulars Schmidt's method of 

 analysis, came to the conclusion in the first place that the gastric 

 juice contains a free chlorine-containing acid. 



1 Lehmann, Physiological Chemistry. Cavendish Society, edition 1853, Vol. n. 

 p. 44. 



2 Bernard and Barreswill, Claude Bernard, Legons de Phys. Exptr. appliqute a la 

 Mtdecine, 1856, Vol. n. 



3 Kiihne, Lehrbuch d. physiol. Chemie, p. 31. 



4 Laborde, 'Nouvelles recherches sur 1'acide libre du sue gastrique.' Gazette 

 medicale de Paris, 1874, No. 3334. 



5 Szabo, ' Beitrage zur Kenntniss der freien Saure des menschlichen Magensaftes.' 

 Zeitsch.f.phys. Chemie, Vol. i., p. 140. 



