76 PROXIMATE PRINCIPLES OF THE FIRST CLASS. 



phosphate of lime is discharged from the body by the urine, the 

 perspiration, mucus, &c. Much the larger portion is discharged by 

 the urine. A small quantity also occurs in the feces, but this is pro- 

 bably only the superfluous residue of what is taken in with the food. 



5. CARBONATE OF LIME. Carbonate of lime is to be found in 

 the bones, and sometimes in the urine. The concretions of the 

 internal ear are almost entirely formed of it. It very probably 

 occurs also in the blood, teeth, cartilages, and sebaceous matter; 

 but its presence here is not quite certain, since it may have been 

 produced from the lactate, or other organic combination, by the 

 process of incineration. In the bones, it is in much smaller quan- 

 tity than the phosphate. Its solubility in the blood and the urine 

 is accounted for by the presence of free carbonic acid, and also of 

 chloride of potassium, both of which substances exert a solvent 

 action on carbonate of lime. 



6. CARBONATE OF SODA. This substance exists in the bones, 

 blood, saliva, lymph, and urine. As it is readily soluble in water, 

 it naturally assumes the liquid form in the animal fluids. It is 

 important principally as giving to the blood its alkalescent reaction, 

 by which the solution of the albumen is facilitated, and various 

 other chemico-physiological processes in the blood accomplished. 

 The alkalescence of the blood is, in fact, necessary to life ; for it is 

 found that, in the living animal, if a mineral acid be gradually 

 injected into the blood, so dilute as not to coagulate the albumen, 

 death takes place before its alkaline reaction has been completely 

 neutralized. 1 



The carbonate of soda of the blood is partly introduced as such 

 with the food ; but the greater part of it is formed within the body 

 by the decomposition of other salts, introduced with certain fruits 

 and vegetables. These fruits and vegetables, such as apples, cher- 

 ries, grapes, potatoes, &c., contain malates, tartrates, and citrates 

 of soda and potassa. Now, it has been often noticed that, after 

 the use of acescent fruits and vegetables containing the above salts, 

 the urine becomes alkaline in reaction from the presence of the 

 alkaline carbonates. Lehmann 2 found, by experiments upon his 

 own person, that, within thirteen minutes after taking half an ounce 



1 Cl. Bernard. Lectures on the Blood ; reported by W. F. Atlee, M. D. Phila- 

 delphia, 1854, p. 31. 



2 Physiological Chemistry. Philadelphia ed., vol. i. p. 97. 



