LACK OF PHOSPHATES AND EARTHS. 845 



as well as the unequal resistance of man and other animals toward this 

 action of acids has already been discussed in Chapter XV. 



Lack of Phosphates and Earths. With the exception of the value of 

 the alkaline earths as carbonates and more especially as phosphates in 

 the physical composition of certain structures, such as the bones and 

 teeth, their physiological importance is almost unknown. The importance 

 of calcium for certain enzymotic processes and of calcium ions for the 

 functions of the muscles, and especially for cell life, gives an indication of 

 the necessity of the alkaline earths to the animal organism. Little is 

 known of the need of these earths in adults, and no average results can 

 be given. The same is true for the need of phosphates or phosphoric acid,, 

 whose value is recognized not only in the construction of the bones, but 

 also in the functions of the muscles, the nervous system, the glands, the 

 organs of generation, etc. The extent of this need is most difficult to 

 determine, as the body shows a strong tendency, when increased amounts 

 of phosphorus are introduced, to retain more than is necessary. The 

 need of phosphates, which, according to EHRSTROM/ corresponds in adults 

 to a minimum of 1 to 2 grams phosphorus, is relatively smaller in adults 

 than in young, developing animals, and in these latter the question of the 

 result of an insufficient supply of earthy phosphates and alkaline earths 

 upon the bone tissue is of special interest. For details we refer to Chap- 

 ter X and to the cited work of ALBU-NEUBERG. 



Another important question is, How far do the phosphates take part 

 in the construction of the phosphorized constituents of the body or to 

 what extent are they necessary? The experiments of ROHMANN and his 

 pupils 2 with phosphorized (casein, vitellin) and non-phosphorized pro- 

 teins (edestin) and phosphates show that with the introduction of casein 

 and vitellin a deposition of nitrogen and phosphorus takes place, while 

 with non-phosphorized protein and phosphates this does not seem to 

 occur. The body apparently does not have the power of building up 

 the phosphorized cell constituents necessary for cell life from non-phos- 

 phorized proteins and phosphates. On the contrary, according to the 

 observations of several investigators, the lecithins seem to possess this 

 power. As known from the investigations of MEISCHER, the develop- 

 ment of generative organs of the salmon, which are very rich in nuclein 

 substances and phosphatides, from the muscles which are relatively poor 

 in organic-combined phosphorus, seem to indicate a synthesis of phos- 

 phorized organic substance from the phosphates. The recent investiga- 

 tions of HART, MACCOLLUM and FULLER, S who found that pigs with food 

 poor in phosphorus develop just as well with inorganic phosphates as 



1 Skand. Arch. f. Physiol., 14. 



2 See Marcuse, Pfliiger's Arch., 67, and also footnote 2, page 826. 



3 Hart, MacCollum and Fuller, Amer. Journ. of Physiol., 23. 



