274 DIGESTION. 



for the present remain undecided whether there is any substance 

 soluble in water, for which the ordinary animal membranes would 

 be absolutely impermeable ; for Cl. Bernard's experiment, which 

 appeared to show that the curara poison could not penetrate through 

 an animal bladder, requires to be repeated, whilst Bernard is no 

 doubt in error when he believes that he has convinced himself 

 that emulsin and diastase are incapable of penetrating animal 

 membranes ; these bodies, like albumen, undoubtedly, however, 

 possess only a small capacity for penetrating animal membranes. 

 With regard to the curara poison, its chemical qualities have been 

 so imperfectly investigated, that we are not yet justified in assuming 

 anything more than that the reason why it exerts no poisonous 

 actions in the intestinal canal may probably be due either to the 

 fact that it undergoes decomposition in that region, or that it 

 enters into combinations which are innoxious to the animal 

 organism. If, moreover, gum, emulsin, diastase, and curara are 

 in point of fact resorbed in much smaller quantities than we 

 should have expected from endosmotic experiments, we must not 

 regard it as impossible that the physical constitution of the 

 intestinal coats may here exert a special influence ; for we know 

 that endosmotic experiments often yield different results, accord- 

 ing as the mucous or the serous surface of a membrane be turned 

 to the salt that is to be diffused, and that (for example) mem- 

 branes of caoutchouc and animal membranes act quite differently 

 from one another in regard to water and alcohol. All such 

 relations as these should be clearly comprehended before we 

 venture to form a definite opinion with respect to the behaviour of 

 gum in the intestinal canal, or to assume the existence of vital 

 forces opposing its absorption. At present, therefore, we know 

 nothing more than that the Potiones gummosa, which are such 

 favourite medicines with the physicians of the rational school, can 

 yield to the animal organism only an extremely small quantity of 

 material, and that only of a nature to support the respiratory 

 process ; and that their uses if they are of any use can be 

 merely negative in acute diseases. 



As an object of food starch is well known to be the most im- 

 portant of all the carbo-hydrates ; we know that it is one of those 

 substances which must undergo a preliminary metamorphosis in 

 order to be resorbed, that it is converted into dextrin and sugar 

 (lactic acid being produced only in a limited degree), and finally, 

 that the saliva and pancreatic juice are the means by which this 

 re-arrangement is effected in the atoms of starch. We have so 



