PHOSPHATE OF LIME. 417 



food a sufficient quantity of this earthy salt ; for in the vegetable 

 kingdom, we find certain nitrogenous bodies which, like the protein- 

 compounds of the animal organism,, always contain some phosphate 

 of lime, as for instance, vegetable albumen, legumin, and gluten. 



Phosphate of lime, is, however, also formed within the animal 

 organism. If the experiments of von Bibra, showing that the bones 

 of young creatures contain relatively more phosphate of ime than 

 those of older ones, appear to be opposed to the view ttiat the 

 phosphate of lime is formed from the carbonate, the numerous 

 analyses of Valentin* prove that newly formed bones, or parts of 

 bones, always contain a greater quantity of carbonate of lime before 

 they are provided with their proper quantity of phosphate of lime. 

 If we review the different substances taking part in the metamor- 

 phosis of the animal tissues, it appears, as a necessary conclusion, 

 that phosphate of lime must be formed from its proximate con- 

 stituents. We know that several animal substances contain phos- 

 phorus in an unoxidised state, and that they are not removed from 

 the organism till they are perfectly decomposed, that is to say, 

 till they are partially oxidised ; in this process the phosphorus 

 must be converted into phosphoric acid. We further know that very 

 many animal substances also contain sulphur, and in their decom- 

 position in the animal body form not only sulphuric acid, but also 

 uric, hippurie, and other acids, which must partially decompose the 

 alkaline phosphates that find their way into the body from with- 

 out, that is to say, by the seeds of the cereals and leguminous plants, 

 so that the liberated phosphoric acid must combine with the lime 

 which enters the animal body with the vegetable food or with the 

 water used as drink. We have an opportunity of almost directly 

 observing the process of the new formation of phosphate of lime 

 from its proximate constituents in the development of the chick 

 within the egg ; for the observations of Front and Lassaigne show 

 that during incubation, such a quantity of carbonate of lime is 

 transferred from the shell of the egg to the yolk, that the augment- 

 ation of the phosphate of lime with the growth of the chick during 

 incubation, is not more than can be accounted for. 



Valentin's opinion is based on the following observations : 

 In the carious tibia of a man, aged 38 years, he found 44'12-g- 

 of ash containing 77'93 of phosphate, and 15*04 of carbo- 

 nate of lime, while the tibia of a healthy man of the same 

 age yielded 61'98-g- of ash, in which were contained 84 of phos- 

 phate, and 12'8 of carbonate of lime. Hence, in this case, the 

 * Repert. f. Anat. u. Physiol. 1839, S. 306 ff. 



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