FORMATION OF HYDROCHLORIC ACID. 477 



also, or both, take part in the formation of free acid is disputed. 1 There 

 can be no doubt that the hydrochloric acid of the gastric juice origin- 

 ates in the chlorides of the blood, because, as is well known, a secretion 

 of perfectly typical gastric juice takes place in the stomachs of fasting 

 animals or those which have starved for some time. As the chlorides 

 of the blood are derived from the food, it is easily understood, as shown 

 by CAHN, 2 that in dogs after a sufficiently long common-salt starva- 

 tion, the stomach secreted a gastric juice containing pepsin, but no free 

 hydrochloric acid. On the administration of soluble chlorides, a gastric 

 juice containing hydrochloric acid was immediately secreted. The 

 conditions are not so simple, because in the first case not only does the 

 amount of hydrochloric acid diminish but, as shown by WOHLGEMTJTH 

 and then by KUDO, the quantity of juice diminishes greatly, and on the 

 introduction of NaCl the quantity of juice secreted increases. Accord- 

 ing to PuGLiESE 3 the gastric juice in starvation, after a certain time, 

 has a neutral reaction, and the introduction of NaCl does not now change 

 its properties. In the secretion of free acid it is assumed by PUGLIESE 

 that the gland cells, which decompose the chloride, have sufficient 

 amounts of protein at their disposal. On the introduction of alkali 

 iodides or bromides, KULZ, NENCKI and SCHOUMOW-SIMANOWSKI 4 have 

 shown that the hydrochloric acid of the gastric juice is replaced by HBr, 

 and to a less extent by HI. The secretion of free hydrochloric acid 

 from the alkaline blood has been explained in various ways, but as yet 

 no satisfactory theory has been suggested. 5 



In regard to the -secretion of pepsin we must recall that this last 

 is not already produced, but is formed from a preliminary step, a pep- 

 sinogen or propepsin. LANGLEY 6 has positively shown the existence 

 of such a substance in the mucous coat. This substance, propepsin, 

 shows a comparatively strong resistance to dilute alkalies (a soda solu- 



1 See Heidenhain, Pfluger's Arch., 18 and 19, and Hermann's Handbuch, 5, part I, 

 " Absonderungsvorgange;" Klemensiewicz, Wien. iSitzungsber,. 71; Frankel, Pfluger's 

 Arch., 48 and 50; Contejean. 1. c.; Kranenburg, Archives Teyler, Ser. II, Haarlem, 

 1901; and Mosse, Centralbl. f. Physiol., 17, 217; Fitzgerald, Proc. Roy. Soc. B. 82, 

 83; L6pez-Suarez, Bioch. Zeitschr. 46, 490 (1912). 



2 Zeitschr. f . physiol. Chem., 10. 



3 Wohlgemuth, Arbeiten aus d. pathol. Institute, Berlin, 1906; Kudo, Bioch. 

 Zeitschr. 16, 217 (1909), Pugliese, Maly's Jahresb., 36, 394. 



4 K\ilz, Zeitschr. f. Biologic, 23; Nencki and Schoumow, Arch, des sciences biol. 

 de St. Petersbourg, 3. 



5 Koeppe, Pfluger's Arch., 62; Benrath and Sachs, ibid., 109; Maly, see v. Bunge's 

 Lehrbuch der physiol. u. pathol. Chem., 4. Aufl., 1898; Schwarz, Hofmeister's Bei- 

 trage. 5, 



6 Schiff, Legons, sur la physiol. de la digestion, 1867, 2; Langley and Edkins, Journ. 

 of Physiol., 7. 



