352 CHEMISTR Y OF THE DIGESTIVE PROCESSES. 



end of the process hydrochloric acid passes over. In addition, he tried 

 to obtain lactic acid from gastric juice, but with negative results. 



The remarkable results so obtained by Prout were confirmed by 

 Children 1 in England, by Braconnot 2 in France, and by Dunglison 

 and Emmet, 3 with gastric juice obtained from Beaumont's case of 

 fistula. 



When the period at which they were carried out is considered, it 

 must be admitted that these experiments of Prout were most ingenious, 

 and he well deserves the honour of being the first to awaken the minds 

 of men to the conception that the animal organism was capable of 

 producing such a substance as hydrochloric acid. 4 Physiological chemists, 

 however, were chary in believing that the gentler forces of the animal 

 organism were capable of producing such a substance as hydrochloric 

 acid, which they were unable to obtttin experimentally except by the 

 use of potent inorganic reagents. Accordingly, objections flowed in 

 against Prout's work. 



Claude Bernard and Barreswil 5 showed that when sodium chloride 

 was added to a solution of lactic acid, and the mixture distilled, hydro- 

 chloric acid appeared in the distillate towards the end of the process 

 when the mixture was beginning to grow solid. They concluded that the 

 free acid of the gastric juice was lactic acid. Lehmann 6 ascribed the 

 free hydrochloric acid of Prout's distillation experiment to the action of 

 the lactic acid, concentrated by evaporation, on the calcium chloride also 

 present in gastric juice. Many other observers were also -agreed that 

 the free acid in gastric juice was lactic acid. 7 Blondlot 8 about this time 

 enunciated the hypothesis that the acidity of the gastric juice was due 

 in part to acid calcium phosphate, and evolved a theory, closely 

 resembling a much more recent one by Maly, as to the origin of the 

 acid by the formation of this substance, accompanied by traces of hydro- 

 chloric and phosphoric acids in the stomach wall, from the sodium 

 chloride and calcium phosphate of the blood. 9 In presence of hydro- 

 chloric acid it is now known that part of any calcium phosphate present 

 would be resolved into acid phosphates, but the amount of calcium 

 phosphate present in gastric juice is altogether insufficient to account for 

 any appreciable part of its acidity. 



While the subject was still in this vexed condition, Bidder and 

 Schmidt's 10 classical work on digestion appeared, containing the results 

 of Schmidt's experiments, to which reference has already been made. As 



1 Annals of Philosophy, July 1824. 



2 Ann. de chim., Paris, 1835, tome lix. p. 348. 



3 Published with Beaumont's results, 1834. 



4 As is often the case in great discoveries, Prout seems not to have been much in time 

 ahead of his fellows. Tiedemann and Gmelin state in the preface to their classical work, 

 "Die Verdauung nach Versuchen," 1826 (while admitting Prout's priority), that independ- 

 ently they had found hydrochloric acid in distilling various gastric fluids, and a month 

 later first saw Prout's publication. However, Prout was clearly ahead of them, both in the 

 distillation method, and in its ingenious confirmation by analytical results, as described in 

 the text. 



5 Compt. rend. Acad. d. sc., Paris, 1844-5 ; "Legons de physiol. exper. applique" a la 

 me"d.," 1856, tome ii. p. 397. 



6 Ber. d. Sachs. Gesellsch. d. Wissensch., Leipzig, 1847. 



7 Pelouse, Compt. rend. Acad. d. sc., Paris, tome xix. p. 1227; Thomson, Lcmd. 

 Edin. and Dub. Phil. Mag., London, 1845. 



8 "Traite analytique de la digestion," 1843; Jahresb. ii. d. Fortschr. d. ges. Med., 

 Erlangen, 1851, Bd. i. S. 97 ; 1858, Bd. i. S. 37. 



9 See p. 361. 



10 "Die Verdauungssafte und der Stoffwechsel," Mitau u. Leipzig, 1852, S. 44. 



