MECHANICAL PHENOMENA. 61 



opportunity of exerting their specific effects. How much of 

 such a secretion occurs, and its quality, can, however, only 

 be surmised. If no food has been introduced through the 

 mouth, and no "psychic" or other secretion from the stomach 

 has in consequence been called forth, little or no pancreatic 

 cr intestinal juice of any kind may be present in the intes- 

 tine. This urges upon us the necessity of introducing into 

 the rectum only those foods which can be taken up directly by 

 the lower portions of the alimentary tract. Certain foods 

 are already in this condition, while others must first be 

 digested outside of the body, or have introduced along with 

 them those ferments which are found in the body and are 

 capable of so acting upon the various constituents of the 

 nutrient enemas that they are converted into readily absorb- 

 able substances. Unless this chemical side of rectal feeding 

 is considered, we must fail in the objects which we wish to 

 attain by these artificial means. 



