86 INORGANIC INGREDIENTS. 



Calcium Fluorid (CaFl 2 ) exists in the bones and in the teeth, 

 and is of little importance. 



Magnesium Salts. Magnesium phosphate (Mg 3 PO 4 ) is found 

 wherever calcium phosphate is found, and the two together are 

 frequently spoken of as the " earthy phosphates." It is discharged 

 by the urine. 



Magnesium Carbonate (MgCO 3 ). A trace of this salt is found 

 in the blood. 



Ammonium Salts. Traces of ammonium chlorid (NH 4 C1) are 

 found in the gastric juice and in the urine. 



Iron. Iron is present in the hemoglobin of the blood, in the 

 hair, the bile, and the urine. Its presence in the coloring-matter 

 of the blood is its most striking characteristic. It exists in the 

 blood combined with the other chemical elements, and not as an 

 oxid. The total amount of iron in the blood of the body of a 

 man weighing 65 kilograms is about 2.71 grams. 



Office of Iron. The office of iron is not understood. It is re- 

 garded as a remarkable fact that without iron chlorophyll, the green 

 coloring-matter of plants, cannot be formed in other words, that 

 vegetable life is interfered with ; and it is believed that its pres- 

 ence in the coloring-matter of the blood of an animal is equally 

 necessary for its nutrition. 



Source of Iron. All animal food containing blood contains 

 iron. In addition to this, iron is taken into the body in rye, 

 barley, oats, wheat, peas, and strawberries. 



Avenues of Discharge. A small amount only of iron is dis- 

 charged in the bile and the urine. After serving its purpose in 

 the blood it is probably deposited in the hair. 



lodin (I). This element occurs in the thyroid gland. 



Silicon (S). It is not known in exactly what form silicon 

 exists in the body, possibly as silicic acid. 



Oxygen (O). This gas is absorbed from the air, and exists 

 in the blood principally in loose combination with the hemoglobin, 

 though some of it is doubtless free. 



Hydrogen (H). Hydrogen is found in the alimentary canal 

 and in the expired air, having been absorbed by the blood from 

 the intestine. 



Nitrogen (N). Nitrogen is absorbed from the air by the 

 blood, in which it exists in a dissolved state. Some nitrogen is 

 formed also within the body. 



Marsh-gas (CH 4 ). This gas is found in the expired air, like 

 hydrogen, having been absorbed from the intestines. Reiset found 

 that thirty liters were expired in twenty-four hours. 



Ammonia (NH 3 ). A small amount of ammonia is found in 

 the expired air, probably derived from the blood. 



Sulphuretted Hydrogen (H 2 S). This gas is found in the 

 intestines. 



