220 GASTRIC DIGESTION. 



ing to the observations of Beaumont and Silliman, was 1005 ; but later, F. G. 

 Smith found it in one instance, 1008, and in another, 1009. There is every 

 reason to suppose that the fluid, in the case of St. Martin, was perfectly nor- 

 mal, and 1005 to 1009 may be taken as the range of the specific gravity of the 

 gastric juice in the human subject. 



The gastric juice is described by Beaumont as inodorous, when taken 

 directly from the stomach ; but it has rather an aromatic and a not disagree- 

 able odor when it has been kept for some time. It is a little saltish, and its 

 taste is similar to that of " thin, mucilaginous water slightly acidulated with 

 muriatic acid." 



It has been found by Beaumont, in the human subject, and by those who 

 have experimented on the gastric juice of the lower animals, that this fluid, 

 if kept in a well stoppered bottle, will retain its chemical and physiological 

 properties for an indefinite period. The only change which it undergoes is 

 the formation of a pellicle, consisting of a vegetable, confervoid growth, upon 

 the surface, some of which breaks up and falls to the bottom of the vessel, 

 forming a whitish, flocculent sediment. In addition to this remarkable fac- 

 ulty of resisting putrefaction, putrefactive changes are arrested in decompos- 

 ing animal substances, both when taken into the stomach and when exposed 

 to the action of the gastric juice out of the body. 



There are on record no minute quantitative analyses of the human gastric 

 juice, except those by Schmidt, of the fluid from the stomach of a woman 

 with gastric fistula ; and in this case there is reason to suppose that the se- 

 cretion was not normal. The analysis of the gastric juice of St. Martin by 

 Berzelius was not minute. The analyses of Schmidt give less than six parts 

 per thousand of solid matter, while Berzelius found more than twelve parts per 

 thousand. In all the comparatively recent analyses, there have been found 

 a free acid or acids, a peculiar organic matter, generally called pepsine, and 

 various inorganic salts. 



The following analysis by Bidder and Schmidt gives the mean of nine 

 observations upon dogs : 



COMPOSITION OF THE GASTRIC JUICE OF THE DOG (BIDDER AND SCHMIDT). 



Water 973-062 



Ferment (pepsine) 17-127 



Free hydrochloric acid 3'050 



Potassium chloride 1*125 



Sodium chloride 2-507 



Calcium chloride 0-624 



Ammonium chloride 0*468 



Calcium phosphate 1-729 



Magnesium phosphate 0-226 



Ferric phosphate 0-082 



1,000-000 



In another series of three observations, in which the saliva was allowed to 

 pass into the stomach, the proportion of free acid was 2-337, and the propor- 

 tion of organic matter was somewhat increased. 



