INORGANIC SALTS, STIMULANTS, AND CONDIMENTS. 925 



ably in the liver, but the final excretion of the iron takes place 

 mainly through the walls of the intestine. 



Accessory Articles of Diet. Under this general term we may 

 include all those bodies classed as condiments, flavors, and stimu- 

 lants, which we habitually take in our diet in order to enhance the 

 attractiveness of the food. These substances may or may not 

 have some heat value to the body that is, they may undergo 

 oxidation with the liberation of heat energy; but, in general, their 

 value in nutrition is due to other properties. 



The Flavors and Condiments. Perhaps the most important 

 influence exerted by these bodies is that by making the food appe- 

 tizing they increase the secretion of gastric juice. The origin of 

 the so-called psychical secretion has been described (p. 775), and 

 there can be little doubt that the palatableness of food influences 

 greatly the facility with which its gastric digestion is accomplished. 

 It is said, in fact, that dogs will refuse to eat food that has been 

 deprived entirely of its sapidity and flavor, preferring rather to 

 starve. Some of these substances (pepper), as also the stimulants 

 (alcohol), may have an additional value in that they increase the 

 rapidity of absorption from the stomach. Gautier divides the 

 condiments into the following classes: (1) Aromatics, comprising 

 vanilla, anise, cinnamon, nutmeg, and other similar essential oils. 

 (2) Peppers. (3) The alliaceous condiments, garlic, mustard, 

 tc. (4) The acid condiments, vinegar, citron, pickles, etc. (5) 

 The salty condiments, such as table salt. (6) The sugar condiments. 



The Stimulants. Under this head we include alcohol, tea, coffee, 

 chocolate, or cocoa, and meat extracts (beef tea, etc.). Regarding 

 the last mentioned substance, its physiological value has been made 

 clear by the work of Pawlow (p. 775). Meat extracts of various 

 kinds contain secretogogues which stimulate the gastric glands to 

 secretion. In themselves they may contain very little actual 

 foodstuff. Liebig's extract contains some protein, gelatin, and gly- 

 -cogen, which form an actual nourishment, but its specific value 

 as a gastric stimulant depends upon other constituents, possibly the 

 nitrogenous extractives, creatin, xanthin, carnin, etc. Coffee 

 and tea owe their well-known stimulating action to the presence 

 of an alkaloid, caffein or trimethyl-xanthin. It may be considered 

 as xanthin in which three of the hydrogen atoms have been re- 

 placed by methyl (CH 3 ) groups, as is indicated in the following 

 structural formulas: 



HN CO CH 3 N CO 



CO i-NH CO C N< CH ' 



CH 3 N C N' 



Xanthin. Caffein. 



