330 



STOMACH AND INTESTINE. 



rently from dead animals) at 1'72, 1'80, M5, 

 after feeding with hay, bones, and peppercorns 

 respectively; Lehmann at an average of 1'4 ; 

 Bidder and Schmidt at 2'694 in the gastric 

 juice of a dog with deligated salivary ducts, 

 2'883 in another dog in whom they were free, 

 and 1-385 from a sheep. These latter high 

 numbers indicate that, whatever may be the 

 influence of an admixture of food or saliva in 

 increasing the residuum of the gastric juice, it 

 is more than counterbalanced by the loss 

 which attends the analysis of small quantities. 

 The first of these three quantitative analyses 

 by Bidder and Schmidt I have made the ba- 

 sis of a calculation *, according to which the 

 specific gravity of the gastric juice would be 

 1003'3, an estimate that tolerably agrees 

 with the observations of Lassaigne and Silliman. 



The quantity of the gastric juice is even less 

 accurately established. From Beaumont's 

 experiments, it would appear that at least 

 eight ounces may be secreted in an hour. 

 It is, however, not impossible that ten times 

 this amount may be poured out during the 

 digestive process. For Bidder and Schmidt's 

 observations on animals give an average of 

 about i^ th of the weight of the whole body 

 per hour, with a maximum of ^V tn m the 

 same period. But it is probable that the 

 latter proportion exceeds that which could be 

 secreted by a human being f in the same space 

 of time. 



Chemical composition. In inquiring into the 

 chemical composition of the gastric juice, it 

 will be convenient successively to consider its 

 acid, its saline, and its animal constituents. 



The gastric acid. Although this obvious 

 and unmistakeable character of the gastric 

 juice has been recognised for more than 150 

 years, yet the nature of the acid on which it 

 depends is probably still regarded as un- 

 certain. An impartial and searching criticism 

 of all the numerous and conflicting analyses 

 that have been made would far exceed the 

 limits of this essay: even had the author 

 (what he has not) the abilities and leisure 

 necessary to such a task. The reader will 

 therefore only expect such a sketch, as may 

 include some of the chief facts which justify 

 us in preferring, if not in adopting, one par- 

 ticular view. 



Not to mention those exceptional instances 

 in which acetic, butyric, or other acids, have 

 been found in inefficient quantity in the con- 

 tents of the stomach, there are at least three 

 views of sufficient importance to demand 



* This calculation is founded on a method sug- 

 gested by Schmidt, and quoted by Lehmann (Op. 

 cit. Bd. iii. pp. 4, 5, 6.). 1 have assumed that the 

 condensation of the ferment on solution equals that 

 of albumen ; that the chlorides of calcium and am- 

 monium stand about midway between those of po- 

 tassium and sodium in this respect ; and that the 

 hydrochloric acid occupies no bulk at all. On these 

 suppositions, the 26'938 grains of residuum would 

 take the space of 23-617 grains of water ; whence 

 100023-617 + 26-938 = 1003-3. 



f In a person of average weight, the above pro- 

 portion of ^th of the whole body would correspond 

 to a secretion of about seven pints (nearly one 

 gallon) of gastric juice in an hour. 



some notice. The first of these regards the 

 gastric acid as the hydrochloric : the second as 

 the lactic. While the third attributes the acid- 

 ulous character of the secretion to the presence 

 of a salt, the acid phosphate or, as it is some- 

 times incorrectly termed, the superphosphate* 

 of lime. 



The latter view, which denies the presence 

 of a free acid, is the more recent of the three. It 

 rests solely upon the statements of Blondlot f; 

 from whose writings we select some important 

 details, which are directly contradicted by the 

 concurrent testimony of other chemists, and 

 even by his own later researches. According 

 to him, the gastric juice is precipitated by 

 lime, does not act upon chalk, and contains 

 no chloride of calcium. He also states (or 

 rather implies) that biphosphate of lime is 

 decomposed by incineration, so as to leave a 

 neutral residue. Each of these statements is 

 met by Lassaigne, Huenefeld, Melsens, Dumas, 

 Bernard, and various other authorities, with 

 a direct denial. And in a more recent Memoir, 

 Blondlot himself lays especial stress upon the 

 presence of a large quantity of chloride of cal- 

 cium, the absence of which salt he had previously 

 insisted on.{ After these remarks, it is un- 

 necessary to detain the reader by any further 

 consideration of the various other errors 

 qualitative as well as quantitative which in- 

 validate the chemistry of this observer. But 

 it is impossible to make these necessary allu- 

 sions to Blondlot's analyses without passing a 

 tribute to his talent, in devising an operation 

 to which we owe all the brilliant experiments 

 that have lately done so much for the physio- 

 logy of digestion. 



Of the two remaining views, the parti- 

 sans of each were, until lately, so equal in 

 number, in repute, and in the validity of their 

 arguments, that few physiologists could decide 

 in favour of either : and those who could 

 not suspend their judgment, were probably 

 beginning to believe in both. 



On the side of lactic acid was the united 

 testimony of Chevreul, Lassaigne, Thomson, 

 Lehmann, Payen, Bernard, and Frerichs ; 

 who had all verified its presence in gastric juice, 

 sometimes when unmixed with food. While 

 against the analyses of Prout , Dunglison, 

 Braconnot, Tiedemann, and others in which 

 hydrochloric acid was either lost from the 



* The formula of which is CaO, 2 HO, P2 O 5 . 



t Loc. cit. 



j Compare Op. cit. pp. 246. 250., and Comptes 

 Rendus, t. xxxiii. p. 118. 



This allusion to Dr. Front's analyses may seem 

 to require some explanation ; the more so, that they 

 have sometimes been misquoted. He analyzed the 

 gastric juice of rabbits who had been fed shortly 

 before death. The contents of the stomach were 

 filtered, and divided into four parts. The first was 

 evaporated to dryness, and ignited. The second was 

 supersaturated with potash, and similarly treated. 

 The third was exactly saturated with the same 

 alkali of known strength. In the case of the first 

 two portions, the saline ash remaining after ignition 

 was dissolved in water, and tested with nitrate of 

 silver for hydrochloric acid. It was presumed that 

 the first method would give the amount of fixed 

 chlorides present j the second, the total amount of 



