390 CALCIFICATION, CONCRETIONS, AND INCRUSTATIONS 



and in the accumulated smegma. 1 The composition is, there- 

 fore, very mixed, and consists of an organic base containing 

 much cholesterin, fats, and soaps, incrusted with inorganic sub- 

 stances, of which ammonio-magnesium phosphate and calcium 

 phosphate are usually the most abundant. 



Prostatic concretions originate in the corpora amylacea 

 (which have been discussed on page 386) through growth by 

 accretion of inorganic salts, until they may reach considerable 

 size. Stern 2 gives the following results of analysis of such a 

 prostatic stone : 



Water ........ ... ........... 8.0 



Organic matter ................... 15.8 



Lime ....................... 37.64 



Magnesia ...................... 2.38 



Soda ...................... 1.76 



Potash ....................... 0.5 



Phosphoric acid ............... .... 33.77 



Iron ...................... trace 



Stones. 3 These may be formed in the bronchi, 

 through accretion about an inorganic nucleus, similar to the 

 formation of calculi in other epithelial-lined passages ; or they 

 may consist of calcined areas of lung tissue or peribronchial 

 glands, which have been sequestrated through suppuration and 

 have entered the bronchi. In the latter case, the calculi 

 present the usual composition of pathological calcified areas. 

 That the expectorated stones frequently represent calcified 

 tubercles is shown by Stern 3 and by Biirgi, 3 who demonstrated 

 tubercle bacilli in decalcified lung stones. The following per- 

 centage figures are taken from Ott 4 : 



Specimen I. Specimen II. 



Calcium phosphate ........... 52.0 72.8 



Magnesium phosphate ........... 1.0 



Magnesium carbonate ......... 2.0 



Calcium carbonate ........... 13.0 6.0 



Fat and cholesterin ........... 24.0 7.0 



Other organic substances . ....... 4.0 10.0 



Rhinoliths 5 are formed about nasal secretions, blood-clots, 

 and most frequently about foreign bodies. They therefore 

 contain much organic substance in addition to the inorganic 



1 See Zeller, Arch. klin. Chir., 1890 (41), 240. 



2 Amer. Jour. Med. Sci., 1903 (126), 281. 



3 Literature, Poulalion, Thesis, Paris, 1891 ; Stern, Deut. med. Woch., 1904 

 (30), 1414. Biirgi (Deut. med. Woch., 1906 (32), 798) has recently described 

 two cases in which the concretions consisted chiefly of calcium phosphates. 



4 " Chem. Path, der Tuberc.," 1903, p. 92. 



5 Literature, Scheppegrell, Jour. Amer. Med. Assoc., 1896 (26), 874 ; Gerber, 

 Deut. med. Woch., 1892 (18), 1165. 



