PATHOLOGICAL CALCIFICATION 445 



tion will then enter to establish equilibrium, be precipitated, and 

 make way for more calcium, until the amount of deposit prevents 

 further osmotic diffusion. Although suggestive in regard to patho- 

 logical calcification, and probably of importance in the formation 

 of concretions, this conception is difficult toapi)ly to normal ossification; 

 also in pathological calcification one would expect precipitation of 

 calcium to occur in the outermost surface of the degenerated area, 

 soon leading to a shell of inorganic material which would limit the 

 deposition. 



The possibihty of the formation of calcium-binding substances 

 within the degenerated area has always seemed the most attractive, 

 and has received the most attention by investigators. Of the special 

 substances that might be present in such areas that would have a 

 high affinity for calcium, phosphoric acid usually receives first con- 

 sideration, since it is as phosphate that most of the calcium is bound, 

 and also since the possible sources of phosphoric acid in decomposed 

 nucleoproteins and lecithin are so obvious. Less considered in the 

 past, fatty acids offer another possibility, especially in view of the 

 fatty degeneration that so frequently precedes calcification. Proteins 

 might also be formed that would combine calcium, especially dcutero- 

 albumose, which Croftan^^ states has a high degree of affinity for 

 calcium, and which would be present in areas undergoing autolysis. 



Formation of Calcium Soaps. — In favor of the possibility that 

 the calcium is first bound as soaps are the following facts: Calcifica- 

 tion occurs chiefly in places where fatty degeneration has occurred, 

 such as tubercles, atheromatous vessels, etc. In fat necrosis fatty 

 acids are formed, which soon combine wuth calcium to form calcium 

 soaps. Virchow observed calcification in the form of soaps in a 

 lipoma, and Jaeckle^® found that a calcifying Lipoma contained 29.5 

 per cent, of its calcium in the form of calcium soaps. Klotz-^ ob- 

 tained staining reactions in calcifying tissues that suggested the pres- 

 ence of soaps, which he also extracted by solvents, and he strongly 

 urges, as the first step in the formation of pathological calcified 

 masses, that the calcium is first laid down as soaps, afterward under- 

 going a transformation into the less soluble phosphate and carbonate. 

 Fischler and Gross-*^ also obtained microchemical reactions for soaps 

 in the margins of infarcts and in atheromatous areas, but not in 

 caseous areas; they therefore consider that calciimi-soap formation is 

 an important step in the process of pathological calcification, but 

 that it is not essential. The value and the interpretation of the his- 

 tological evidence of the participation of calcium soaps is, however, 

 open to question. 



=5 Jour, of Tuberculosis, 1903 (5), 220. 



2«Zeit. phvsiol. Chem., 1902 (36), 53. 



"Jour. Exper. Med., 1905 (7), 663; 1906 (8), 322. 



28Ziegler's Beitr., 1905 (7th suppl.), 339. 



