460 CALCIFICATION, CONCRETIONS, AND INCRUSTATIONS 



composed of calcium and niagnesiuin phosphate (5), or calcium phos- 

 phate or carbonate (1 each). The tlisintegration is brouglit about 

 through solution of the binding substance and mechanical shattering 

 of the stone into fragments. This occurs but rarely, Bastos ®*^ esti- 

 mating that perhaps one calculus in ten thousand undergoes disinte- 

 gration. 



CORPORA AMYLACEA ^^ 



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 concerning 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 por- 

 tions of one body react one way, while the remainder behaves differ- 

 ently. Seldom if ever do the ordinary concretions of the prostate 

 give all the amyloid reactions characteristically, but the corpora 

 amylacea of the lungs are much more likely to do so (Stumpf).''° It 

 seems improbable that these bodies, which occur in the prostate of 

 every adult, can be the same as the amyloid, which is seldom observed 

 except as the result of serious processes of tissue destruction. Accord- 

 ing 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 prob- 

 able that they should be interpreted as simple concretions of protein 

 nature, Avhich form under certain conditions when a nucleus of some 

 sort (usually pigment, degenerated cells, or inorganic crystals) exists 

 in a stagnating, protein-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 pigments), and 

 occasionally it may react metachromatically with methyl-violet, pos- 

 sibly because of the presence of chondroitin-sulphuric acid derived 

 from the mucin of the cavities where the concretions form, but per- 

 haps for some other unknown reasons. Occasionally pure amyloid 

 may form in the tissues typically concentric (or even crystalline) 

 bodies, as in Ophlil's case, but this is the exception. It seems prob- 

 able that corpora amylacea are usually protein concretions,"^ and 



88a Folia Tirol., 101.'? (8), SI. 



80 Gonoral literature, Posncr, Zcit. kliii. Mod., ISSO (Ifi), 144: Luharscli, 

 Erpcl). allfr. Patliol.. 1894 (L). ISO; Opliiils, .Tour. Exp. :\lo(l.. 1900 (5). Ill; 

 Nunf)I<a\va. Vircliow'a Arch., 1909 (19(5), 221; Briitt, ibid., 1912 (207), 412. 



00 Vircliow's Arch., 1910 (202), 1.34. 



01 Ramsdon'.'^ olisorvations (Pror. Royal Soc, 190.3 (72), 156). on tlic procipi- 

 tation of j)roleiiis l)y tlio action of surface contact may liave some bcarinir on 

 the formation of such protein concretions. 



