804 NUTRITION AND HEAT REGULATION. 



the iron in inorganic form and synthesizing it into a molecule so 

 complex as that of hemoglobin. Experience, however, seem to 

 show that this is possible, although under normal conditions at 

 least our iron is used in organic form. Bunge first isolated such a 

 compound, a nucleo-albumin containing iron, which he prepared 

 from the egg yolk and called hematogen. This compound must 

 serve as the source of the hemoglobin in the developing chick. 

 When the diet is directed especially toward increasing the iron 

 food it would seem to be wiser to choose these compounds, or, better 

 still, the iron-rich foods, rather than medicinal preparations of 

 the inorganic salts. The daily excretion of iron from the body 

 takes place in the feces rather than in the urine. The experiments 

 of Voit upon isolated loops of the intestine, referred to above, show 

 that iron is eliminated from the walls of the intestine. The whole 

 history of the metabolism of iron in the body is surrounded by 

 much uncertainty. After absorption its synthesis to hemoglobin 

 takes place, as to its final stages, in the red marrow, but it is possible 

 that other organs may take part in the formation of intermediate 

 products. As regards its elimination, we know that the breaking 

 down of the hemoglobin, formation of bile pigments, takes place 

 probably in the liver, but the final excretion of the iron is made 

 in some form 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 lies in 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. 689), 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, 

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

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



