APPENDIX. 753 



deficient, and from the diseased condition which is consequent on its 

 withdrawal. In the blood, the quantity of sodium chloride is greater 

 than that of all its other saline ingredients taken together. In the mus- 

 cles, on the otlier hand, the quantity of sodium chloride is less than that 

 of the chloride of potassium. 



Calcium Fluoride, in minute amount, is present in the bones and 

 teeth, and traces have been found in the blood and some other fluids. 



Calcium, Potassium, Sodium, and Magnesium Phosphates 

 are found in nearly every tissue and fluid. In some tissues the bones 

 and teeth the phosphate of calcium exists in very large amount and i s 

 the principal source of that hardness of texture on which the proper 

 performance of their functions so much depends. The phosphate of 

 calcium is intimately incorporated with the organic basis or matrix, but 

 it can be removed by acids without destroying the general shape of the 

 botie; and, after the removal of its inorganic salts, a bone is left soft, 

 tough, and flexible. 



Potassium and sodium phosphates with the carbonates, maintain the 

 alkalinity of the blood. 



Calcium Carbonate occurs in bones and teeth, but in much smaller 

 quantity than the phosphate. It is found also in some other parts. The 

 small concretions of the internal ear (otoliths) are composed of crystal- 

 line calcium carbonate, and form the only example of inorganic crystal- 

 line matter existing as such in the body. 



Potassium and Sodium Carbonates are found in the blood, and 

 some other fluid and tissues. 



Potassium, Sodium, and Calcium Sulphates are met with in 

 small amount in most of the solids and fluids. 



Silicon. A very minute quantity of silica exists in the urine, and in 

 the blood. Traces of it have been found also in bones, hair, and some 

 other parts. 



Iron. The especial place of iron is in haemoglobin, the coloring- 

 matter of the blood, of which a full account has been given with the 

 chemistry of the blood. Peroxide of iron is found, in very small quan- 

 tities, in the ashes of bones, muscles, and many tissues, and in lymph 

 and chyle, albumin of serum, fibrin, bile, milk, and other fluids; and a 

 salt of iron, probably a phosphate, exists in the hair, black pigment, and 

 other deeply colored epithelial or horny substances. 



Aluminium, Manganese, Copper, and Lead. It seems most 

 likely that in the human body, copper, manganesium, aluminium, and 

 lead are merely accidental elements, which, being taken in minute quan- 

 tities with the food, and not excreted at once with the fasces, are absorbed 

 and deposited in some tissue or organ, of which, however, they for^n no 

 necessary part. In the same manner, arsenic, being absorbed, may be 

 deposited in the liver and other parts. 

 48 



