514 AN AM ERIC AX TEXT-BOOK OF PHYSIOLOGY. 



l»ut has been converted into fat. 1 Similar results are characteristic of arsenic 

 and antimony poisoning, and of yellow atrophy of the liver. Rosenfeld has 

 recently shown that much of the tat found in the liver of a dog poisoned 

 with phosphorus is fat transported from the fat repositories of the body (fatty 

 infiltration). The high proteid metabolism, however, of itself would indicate 

 the retention of an unburned part of the proteid molecule, which in this case 

 probably appears as fat - (fatty degeneration, see p. 559). A parallel case of 

 high proteid metabolism is seen in diabetes, where sugar from proteid remains 

 unburned. 



Compounds of Phosphorus with Oxygen. — Of these compounds three 

 oxides ami several acids exist, but only meta- and orthophosphoric acid need 

 attention here. 



Phosphorus Peroxide, P 2 5 , is a white powder, which rapidly absorbs 

 moisture; it is produced by burning phosphorus in dry air. 



Metaphosphoric Acid, HPO s , is said to occur combined in nuclein. 



Preparation. — (1) By dissolving P 2 O s in cold water, 



P 2 5 + H 2 = 2HP0 3 . 



(2) By fusing phosphoric acid, 



H 3 P0 4 = HP0 3 + H 3 0. 



It is converted slowly in the cold, rapidly on heating, into phosphoric acid. 

 ( r\ stalline it forms ordinary glacial phosphoric acid. Metaphosphoric acid 

 precipitates proteid from solution, yielding a body said to be pseudonuclein, 3 

 but this seems to be untrue* (see p. 579). 



Orthophosphoric Acid, H 3 P0 4 . — Salts of this acid constitute all the in- 

 organic compounds of phosphorus in the body, and are called phosphates. 



Preparation. — (1) By heating solutions of metaphosphoric acid, 



HP0 3 + H 2 = H 3 P0 4 . 



(2) By treating bone-ash with sulphuric acid, 



0a ,(P0 4 ) 2 + 3H 2 S0 4 = 3CaS0 4 + 2H 3 P0 4 . 



Properties. — On evaporation of the liquors obtained above, the acid separates in color- 

 less hydroscopic crystals. 



Phosphoric acid forms different salts according as one, two, or three atoms of hydrogen 

 arc supplanted by a metal. Thus there exist primary sodium or calcium phosphates, 



Nail, PO, and Ca<n > ( >' ; the secondary phosphates. Na 2 IIP0 4 and CaHP0 4 : and the 



tertiary phosphates, Na t l'<) 4 and Ca*(P0 4 ) s . On account of their reaction to litmus 

 these salts have been falsely called acid, neutral, and basic, but the secondary salts are, 

 chemically speaking, acid salts. 



The bones contain a large quantity of tertiary phosphate of calcium ; the 

 fluids and cells of the body contain likewise the primary and secondary phos- 



1 J. Bauer: Zeitschrifl fur Biolnrjie, 1871, Bd. 7, S. 63. 



2 Kay, McDermott, and Ltisk : American Journal of Physiology, 1899, vol. iii. p. 139. 



3 L. Liebermann : Berichte der deutschen chemischen Gesellschaft, Bd. 22, S. 598. 

 'Salkowski: Pfiuger's Archiv, 1894, Bd. 59, S. 245; also, Giertz: Zeitschrift fitr physiv- 



logische Chemie, 1899, Bd. 28, S. 115. 



