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early and rapid decay of the teeth in many persons. For this general 

 reason therefore only, we should, a priori, be disposed to attach 

 greater importance to the occurrence of deposits of phosphate of lime 

 than those of phosphate of magnesia. 



Other facts tending to confirm this view are, first, that while 

 deposits of phosphate of lime are frequently met with, those of 

 phosphate of magnesia (not the ammonio-magnesian phosphate) are 

 exceedingly rare ; and second, that the calcareous is of more difficult 

 solubility than the magnesian phosphate. This last circumstance 

 explains probably why phosphate of lime falls as a deposit from 

 acid urine, while phosphate of magnesia remains in solution. 



The particular or special reasons for regarding deposits of phos- 

 phate of lime as of more moment than those of the triple phosphate, 

 are derived from direct pathological observation. I have observed 

 that when this deposit occurs, it is very apt to be persistent ; and 

 when it has disappeared, to return whenever the health is reduced 

 from any cause. I have also noticed that, when it is persistent, it is 

 usually associated with marked impairment of the health, and this 

 often where organic disease does not exist. The prominent symptoms 

 in one case of calcareous phosphatic deposit which I have had under 

 observation for some years, were, great disorder of the digestive or- 

 gans, frequent and distressing headaches, occasional vomiting, debility, 

 emaciation, great irritability of the nervous system, sexual powers 

 weak, pulse slow and feeble, skin cold, urine in excess, of rather low 

 specific gravity, acid when passed, but soon becoming alkaline, mic- 

 turition frequent, with irritation at neck of bladder and in the course 

 of the urethra : teeth much decayed. It should be stated that 

 there is in this case a very slight tendency to paralysis of the right 

 leg, as shown by an occasional sensation of coldness in the limb, and 

 slight deficiency of power in it at times only. This symptom is, 

 however, by no means a constant or necessary one in such cases. 



If these views of the pathology of phosphate of lime be correct, we 

 should expect to find an excess of that phosphate in the urine in great 

 and rapid waste of tissue, during the rapid decay of the teeth, and 

 in cases of mollities ossium. That there is an excess of the calcareous 

 phosphate in the urine in these cases, is shown alike by observation 

 and analysis. 



It is obvious from this imperfect sketch that much remains to be 



