332 



STOMACH AND INTESTINE. 



the results of such a laborious inquiry, there 

 seems little doubt that we ought to regard 

 the balance of evidence as inclining decisively 

 towards a single gastric acid, and that acid 

 the hydrochloric. * 



Whatever the number or nature of the sub- 

 stances to which this acid reaction of the 

 gastric juice is due, there can be no doubt as 

 to their source : namely, the blood. And 

 it is to a derivation of acid from some of 

 the constituents of the latter fluid that we 

 must refer the important fact established by 

 Dr. Bence Jones : namely, that, during diges- 

 tion, the healthy urinary secretion loses that 

 acidity which is proper to it at other periods. 



Salts. As regards the salts of the gastric 

 juice, we can only refer to the accurate analyses 

 alluded to above ; which, while they confirm 

 the large quantity of chlorides mentioned by 

 most observers, exhibit rather less of the 

 chloride of ammonium than the united (but 

 rather vague) statements of many observers 

 would have led us to expect. 



The details of an analysis of the gastric 

 juice may be best comprehended (if not ex- 

 plained) by placing them side by side, with a 

 similar quantitative examination of the liquor 

 sanguinis. The following table-f- exhibits such 

 a comparison, for a thousand parts of both 

 fluids. 



I.lquor 

 Sanguinis. 



Water - - - 903- 

 Animal matters - 88'5 

 Mineral substances - 8'6 



Chlorine - - - 3'G 



Sodium - 3'3 



Potassium (in dog, -2 ?) -3 



Phosphoric acid - -2 



Phosphate of lime - -3 



Phosphate of magnesia '2 

 (Lime corresponding to 

 624 Ca. Cl.) 



1000-0 



Gastric 



Juice. 



973-2 



17-0 



9-8 



5-6 



1-2 



6 



6 



1-2 



2 



3 



1000-0 



Hence, while most of the blood-salts are 

 present in increased quantity in the gastric 

 juice, the chloride of sodium is so greatly di- 

 minished, as to lower the total saline contents 

 of this secretion below those of the liquor 



* It is only many months after writing the above 

 lines that Bidder and Schmidt's admirable treatise 

 (Die Verdauungssaefte und der Stoft'wechsel) has 

 come into my hands. From it I may translate the fol- 

 lowing paragraph (p. 41 ) : " The result of eighteen 

 corresponding analyses was, that pure gastric juice 

 of carnivora, after eighteen to twenty hours' fasting, 

 contained free hydrochloric acid only, without a trace 

 of lactic or any other organic acid : while the gastric 

 juice of herbivora contains, with free hydrochloric 

 acid, small quantities of lactic acid ; which may, 

 however, be referred to their more amylaceous food." 



f Here I have calculated the composition of the 



fastric juice from the purer fluid of Schmidt's first 

 og. That of the liquor sanguinis, which is quoted 

 from Lehmann (vol. ii. p. 153.), may be safety 

 (Id. p. 179.) extended to this animal. To facilitate 

 comparison, both are simplified to one place of deci- 

 mals. And for the same reason, the phosphate of 

 lime in Schmidt's analysis has been assumed to be 

 the biphosphate, and divided into phosphoric acid, 

 and neutral phosphate. 



sanguinis. While the amount of its hydrochlo- 

 ric acid is so great, as not only to compensate 

 this loss, but even to raise the total of its 

 mineral constituents above that of the liquor 

 sanguinis than before. The origin of this acid 

 is obvious. Its mere quantity is sufficient to 

 refer it to the chloride of sodium, which is the 

 most plentiful chloride of the parent fluid. 

 And the remarkable diminution in the sodium 

 of the secreted fluid further confirms this 

 view. Indeed, it is difficult to avoid noticing, 

 that many of the differences between the salts 

 of the two fluids might be included in some 

 such hypothesis as the following: (].) a 

 rapid transudation of the blood-salts generally, 

 followed by their concentration through ab- 

 sorption of part of their water of solution ; 

 (2.) a decomposition of about half of the 

 chlorides, probably of the chloride of sodium*; 

 (3.) a return of the base of this salt into the 

 blood. 



Organic substance, or Pepsine. The addi- 

 tion of alcohol to pure gastric juice, or to a 

 watery infusion of stomach, causes a white 

 flocculent precipitate ; which, when dried at 

 a low temperature, forms a much less volumi- 

 nous mass, of a yellowish grey colour, and a 

 somewhat gummy appearance. This substance 

 reddens litmus, and is soluble in cold water ; 

 but may be again precipitated from its aqueous 

 solution by alcohol. Its ultimate analysis 

 yields sulphur and nitrogen, together with car- 

 bon, hydrogen, and oxygen. But we neither 

 know the exact proportions in which all these 

 elements are present, nor the manner in which 

 they are combined: and may even doubt, 

 whether its composition is really quite defi- 

 nite and constant in different specimens. 



Two analyses of this precipitate have how- 

 ever been made : one by A. Vogel-j-, of the 

 extract of Pig's stomach ; and one by Bidder 

 and SchmidtJ of the pepsine obtained from 

 pure gastric juice. They are as follows : 



Pepsine. 



Vogel. Schmidt. 



Carbon - 5772 53'0 



Hydrogen - - 5'57 6-7 



Nitrogen - 21-09 17-8 



Oxygen;( + other ele- 

 ments, and loss) IG'06 22-5 



Of these two analyses, the latter is pro- 

 bably the more correct one. It offers us a 

 composition closely resembling that of the 

 various protein compounds, from which it 



* Such a decomposition would obviously present 

 many analogies to an electrolysis. But, at present, 

 we should hardly be justified in naming it after this 

 process. That the acid and base are unloosed and 

 separated is certain. But I think no one who has 

 carefully studied the phenomena of current affinity 

 would like definitely to refer the above decomposi- 

 tion to this cause in the existing state of our know- 

 ledge. We may, however, notice, that both the 

 quantity and quality of the chloride of sodium would 

 render it more susceptible to electrolytic action than 

 any other of the salts present in the liquor san- 

 guinis. 



f Simon's Beitraege, Berlin, 1843, p. 108. ; Ann. 

 der Pharmacie, 1831), Apr. p. 36. 



J Op. tit. p. 46. 



