CARBONATE OF LIME. 51 



3. Fluoride of Calcium. (CaFl.) 



This is found only in bones and teeth (both the enamel and den- 

 tine). Marchand finds 1 per cent, of it in human bone ; the quan- 

 tity in human teeth has not been determined. Berzelius found in 

 the ox 4 per cent, of this salt in the enamel, and 5 per cent, in the 

 dentine. It is not known from what alimentary substances it is 

 derived, how it leaves the body, nor the part it acts therein, except 

 by reason of its hardness. 1 



4. Hydrochlorate (and Carbonate and Bicarbonate) of Ammonia. 



(NH 3 HC1.) 



Nothing is known of the functions of these, and it is not demon- 

 strated that the last two are immediate principles. The first exists 

 in the tears, the saliva, and the urine. Whether formed in the body, 

 or derived from the food, is unknown. 



5. Carbonate (and Bicarbonate) of Lime. (CaOC0 2 .) 

 The presence of the latter is only accidental in the human body. 

 The carbonate of lime exists in bones, teeth, cartilages, and the 

 blood. Otoconites are formed almost entirely of it. Traces are 

 found in the ashes of the lungs. It is also found in the concretions 

 (incorrectly called ossifications) of the muscles, arteries, valves of 

 the heart, in false membranes, around fibrous tumors of the uterus, 

 in the dura mater, and in the pineal body. Preputial, salivary, ton- 

 sillary, lachrymal, and certain pulmonary concretions, tubercles (cre- 

 taceous and the common form), and certain urinary, biliary, and 

 arthritic calculi, contain this salt. In all 

 cases it is combined with the phosphate 

 of lime. It is sometimes also found in 

 alkaline human urine. A rare form in 

 the urine is shown by Fig. 3 ; it usually . | ^p 



being an amorphous powder like the phos- \ xaJ^ ^ 



phate of lime. Landerer has also found it 

 in the crystalline lens affected with cata- 

 ract. 



This salt is found in most of the tissues- 



-i n i , .A rare form of carbonate of lime, 



and fluids m an amorphous state e. g. in found in a ikaime urine. 



1 Dr. G. Wilson has demonstrated the existence of fluorine in the blood and in 

 milk; and the. fluoride of calcium exists in many mineral waters, and in plants 

 growing in micaceous soils. 



