DUEATION OF STOMACH-DIGESTION. ' 271 



ach, though, the greater part passes through the alimentary 

 canal and is discharged unchanged in the faeces. Beaumont 

 has shown this to be true in the human subject by experi- 

 ments which he performed, out of the body, with gastric juice 

 taken from St. Martin. 1 In these observations, after a cer- 

 tain portion of the bone had been dissolved, the action was 

 increased by the addition of fresh gastric juice. In the 

 natural process of digestion, the solution of the calcareous 

 elements of bone is more rapid than in artificial digestion, 

 from the fact that the juice is being continually absorbed 

 and secreted anew by the mucous membrane of the stomach. 



Duration of Stomach-Digestion. 



'Now that the relative importance of the stomach and 

 the small intestines in digestion is more fully understood, 

 less interest is attached to the length of time required for 

 the action of the gastric juice upon different articles of food 

 than formerly, when the stomach was regarded as the prin- 

 cipal, if not the sole digestive organ. It was thought at 

 one time that the food was converted in the stomach into a 

 pultaceous mass called chyme, 2 which passed into the intes- 

 tine, where the assimilable portion (the chyle) was separated 

 and absorbed by the lacteals. Eeaumont, in preparing the 

 elaborate table which has been so much quoted, conceived 

 that the simple action of the gastric juice represented the 

 chief part of the digestive process ; and that it was possible, 

 from experiments with this fluid, to ascertain the digesti- 

 bility of different articles. From this point of view he re- 

 gards fatty substances, which are now known to be digested 



1 BEAUMONT, op. cit., p. 200. 



2 The word chyme, like many words used by the earlier physiologists, under 

 the supposition that they represented definite principles, has for some time been 

 practically discarded, on account of its indefinite signification. It is particularly 

 inexact, as the mass resulting from the action of the gastric juice upon the varied 

 articles used as food is composed of many undigested substances, as well as dis- 

 tinct substances resulting from the digestion of different alimentary principles. 



