54 ARTIFICIAL DIGESTION. 



But this interference takes place only in an indirect way, for the section 

 of* those nerves is attended with such a paralysis of the stomach that 

 those movements which so well serve to mix up the food with the gas- 

 tric juice, and expel it through the pyloric valve, are put an end to. 



Bidder and Schmidt, from an examination of four dogs with gastric 

 Effect of section fistnlge, demonstrated that the section of the pneumogastric 

 of the pneumo- nerves does not exert that influence on the secretion of the 

 gastric juice which had been formerly supposed, for both in 

 quantity and composition it remained the same. Even in those cases in 

 which both they and others have observed a diminution in its amount, 

 the result ought, probably, to be referred to the shock given to the entire 

 system by the severity of the operation. 



The acidulating material of the gastric juice is hydrochloric acid. Is 

 it possible by artificial mixtures containing that substance to reduce 

 food articles to a digested condition ? This inquiry introduces a descrip- 

 tion of the experimental investigations which have been made in artificial 

 digestion. 



When water acidulated with hydrochloric acid is kept in contact with 

 Artificial di- albumen, no action is perceptible at ordinary temperatures in a 

 gestion. moderate period of time. If the temperature is raised to about 

 150 a slow dissolution ensues, which becomes better marked as the heat 

 rises toward 212. 



f But if to the weak hydrochloric acid thus made to act on albumen, 

 pepsin is added, the solution takes place with rapidity at moderate tem- 

 peratures. An ounce of water, mixed with twelve drops of hydrochloric 

 acid to which one grain of pepsin has been added, will completely dis- 

 solve the white of an egg in two hours at a temperature of 100. It 

 acts in the same manner on cheese or flesh, these nitrogenized articles 

 being converted into soluble non-coagulable bodies. The acid does not 

 enter into chemical combination with the dissolving organic matter. It 

 may be recovered from the solution by resorting to proper processes. 



When striated muscular tissue is submitted to artificial digestion, it is 

 Artificial di- ^ rst divided into its constituent fasciculi, and the transverse 

 gestion of mus- stride then disappear, the sarcolemma being destroyed. The 

 course of the action seems to be the same in natural diges- 

 tion. In the fcecal matter, shreds of muscular fasciculi still bearing their 

 striation may be discerned. These, having by chance escaped solution 

 during their sojourn in the stomach, have passed through the whole 

 length of the digestive tube unchanged. 



Pepsin the substance resorted to in these experiments may be ob- 

 tained by macerating the mucous membrane of the stomach 



Pepsin, prep- ' & 1-1 



aration and for a short time in lukewarm water. This water, along with 

 properties of. a ^^ O f t ne pepsin, removes various impurities ; it may there- 



