386 CALCIFICATION, CONCRETIONS, AND INCRUSTATIONS 



acid. Out of 121 cases collected by Englisch, 1 in all but 7 

 this was the case, these being composed of calcium and mag- 

 nesium phosphate (5), or calcium phosphate or carbonate (1 

 each). The disintegration is brought about through solution of 

 the binding substance and mechanical shattering of the stone 

 into fragments. 



CORPORA AMYLACEA 2 



In the case of these widely-spread concentric bodies we find 

 the name misleading, for the bodies are not a form of animal 

 starch, as was suggested by their laminated structure and iodin 

 reaction, nor are they so closely related to amyloid material as 

 the name implies. Different authors disagree decidedly con- 

 cerning the staining reactions of these bodies, but it may be said 

 that the reactions are extremely inconstant. Sometimes the 

 corpora are stained bluish or green with iodin, sometimes brown, 

 often little at all ; occasionally they react partly with methyl- 

 violet, but more often they do not ; sometimes portions of one 

 body react one way, while the remainder behaves differently. 

 Seldom if ever do the ordinary concretions of the prostate give 

 all the amyloid reactions characteristically, and the same applies 

 to the corpora amylacea of the lungs. It seems improbable 

 that these bodies, which occur in the prostate of every adult 

 (Posner), can be the same as the amyloid, which is seldom 

 observed except as the result of serious processes of tissue 

 destruction. According to their structure they obey the usual 

 laws of the formation of concretions, having a central nucleus 

 and a structural framework of different composition from the 

 chief substance. It seems most probable that they should be 

 interpreted as simple concretions of proteid nature, which form 

 under certain conditions when a nucleus of some sort (usually 

 pigment, degenerated cells, or inorganic crystals) exists in a 

 stagnating, proteid-rich fluid. At times the resulting concretion 

 may be of such a physical nature that it absorbs iodin readily 

 (just as they often show a marked absorption-affinity for pig- 

 ments), and occasionally it may react metachromatically with 

 methyl-violet, possibly because of the presence of chondroitin- 

 sulphuric acid derived from the mucin of the cavities where 

 the concretions form, but perhaps for some other unknown rea- 

 sons. Occasionally pure amyloid may form in the tissues typic- 

 ally concentric (or even crystalline) bodies, as in OphiiPs case, 



1 Arch. klin. Chir., 1905 (76), 961 (elaborate review). 



2 General literature, Posner, Zeit. klin. Med., 1889 (16), 144; Lubarsch, 

 Ergeb. allg. Pathol., 1894 (I 2 ), 180; Ophiils, Jour. Exp. Med., 1900 (5), 111. 



