1 82 THE POPULAR SCIENCE MONTHLY 



tions just mentioned would have pronounced the same explanation was to be 

 applied to both, or that the acid in the filtered fluid was the phosphoric. 



Additional evidence of the presence of phosphoric acid was believed to 

 be derived from the behavior of the fluid towards solutions of mercury 

 or silver in nitric acid and towards lime water. 



The supposed finding of a mineral acid led Young to comment 

 upon the efficiency of metallic iron recommended by Italian physicians 

 as a tonic, its solution being thereby explained. For, he asks, " does 

 not the uniform eifects of iron in its metallic state prove that an acid 

 is always present in the stomach ? " 



The solvent property of the gastric juice on bones and teeth sug- 

 gested the possibility of its use as a solvent for stone in the bladder. 



A calculus was obtained from Dr. Jacobs of a very firm texture weighing 

 exactly fifty grains. It was introduced into the stomach of one of the large 

 frogs. In two days it was taken out for examination: at first sight it was 

 evident solution had taken place, for the gastric juice which adhered to it was 

 coloured with some of the dissolved stone: it was found to weigh forty-five 

 grains. It was forced into the stomach a second time, where it remained for 

 two days; it now weighed thirty-eight grains: from this, it appears, it is well 

 worthy of more attention. When introduced into the bladder, with the heat of 

 the human body, we have little doubt the gastric juice of frogs would act upon 

 calculi with much efi'ect. The fluid is easily procured, and without the neces- 

 sity, as in other animals, of sacrificing a life every time we wish to obtain it: 

 by means of a teaspoon it is readily brought up from their stomachs. 



With the theory of fermentation rejected, the author proceeds to 

 attempt an explanation of the digestive function. 



Aliment is dissolved by the gastric menstruum; it then passes into the 

 duodenum and meets with bile and pancreatic liquor; after being united with 

 these, a heterogeneous mass is formed called chyme, and from this the lacteals 

 secrete chyle. 



We are Jed to believe this to be the true doctrine, because, as before 

 observed, simple solution will not explain the phenomenon of digestion; nor 

 will the mixture of this dissolved mass, with bile and pancreatic liquor, change 

 it into chyle; for we know chyle is formed when both these fluids are wanting: 

 thus nutrition goes on when the biliary ducts are obstructed, and also when 

 the pancreas is schirrous. That the absorbents have a secreting or digestive 

 power, we learn from the following. Dr. Wistar informs us of a remarkable 

 case, which occurred under his own observation, of a person who was supported 

 for many weeks, by nourishing enemata, alone. Here it can not be said there 

 was bile, gastric and pancreatic liquors to assimilate the injected fluid into 

 chyle; yet chyle was formed and the system nourished. If the lacteals acted 

 the part of simple absorbing, or capillary tubes, their contained fluids ought to 

 partake of the sensible properties of the mass from which they are absorbed. 

 But the reverse of this is the case: chyle has always the same taste, however 

 difl'erent the sensible properties of the contents of the intestines may be, 

 whether they are acid, bitter, etc. We draw a strong argument in truth of 

 this opinion, by turning to the vegetable kingdom, throughout the whole of 

 which the digestive process is seated in the absorbents. Water is to them 

 what the fluids of the primsevijB are to the digestion of man: it dissolves their 



