SOTTKCE OF THE ACIDITY OF THE GASTRIC JUICE. 243 







With the abundant opportunities which have been pre- 

 sented for the chemical study of the gastric juice, not only in 

 the inferior animals, but in man, and in view of the numer- 

 ous elaborate researches into the nature of this fluid by the 

 most skilful physiological chemists of the day, it is a matter 

 of surprise that the question of the existence of free hydro- 

 chloric acid, or its condition as regards combination with the 

 organic matter, is not settled. It certainly cannot now be 

 regarded as settled beyond question. If, as is supposed by 

 Bidder and Schmidt, there be a proportion of chlorine which 

 cannot be accounted for by the quantity of ordinary bases in 

 the gastric juice, it probably does not exist as free hydro- 

 chloric acid, but is in some way united with organic matter. 



In 1786, Macquart indicated the presence of lactic acid 

 in the gastric juice of the calf; attributing to free phosphoric 

 acid, the acidity of the gastric juice of the ox and the sheep. 1 

 Since then there have been numerous analyses in which this 

 principle has been said to be found. Among those who 

 early adopted this view, may be mentioned Chevreul, Graves, 

 Leuret, and Lassaigne. After the -analyses by Prout, in 

 1823, and the observations of Beaumont on the fluid obtained 

 from St. Martin, and until the publication of the experi- 

 ments of Bernard, Yillefranche, and Barreswil, in 1844, the 

 hydrochloric was generally supposed to be the free acid of 



supposes to be the lactic acid. (Traite de Physiologie, Paris, 1861, tome i., p. 

 203.) 



1 MACQUART, Memoire sur le Sue Gastrique des Animaux Ruminants. Me- 

 moires de la Sociele Royale de Medecine, Paris, 1786, p. 355 et seq. In a pound 

 of gastric juice from tire calf, obtained from animals just killed, Macquart found 

 forty-eight grains of lactic acid (p. 377). It is probable that the large quantity 

 of acid thus obtained was derived in part from the milk taken into the stomach 

 of the animal ; especially as Macquart mentions that sugar was likewise found, 

 which certainly is not a normal constituent of the gastric juice. At the time of 

 the observations of Macquart, the formation of lactic acid from sugar was not 

 known. In fact, it was only in 1780 that this acid was first described by Scheele; 

 and it was many years before its formation from sugar, muscular tissue, etc., waa 

 described. 



