442 CALCIFIC ATlOy, COyCREllOyfi, A.VZ) lyCRU STATIONS 



necrosis) this may occur. In calcification at all stages the propor- 

 tion of calcium carbonate and phosphate was found quite constant, 

 and exactly the same as in normal bone; namely, in the proportion 

 expressed by the formula 3(Ca.5(POJo) : CaCO,, which Hoppe-JSeyler 

 advanced to express the composition of the salts of bone. Hence it 

 seems probable that there are no essential differences between the 

 processes of ossification and pathological calcification,-^'' and there 

 seems to be as yet no reason for assuming that in the former calcium 

 soaps constitute an essential step in the process. 



Phosphoric Acid in Calcification. — It has generally been assumed 

 that in normal ossification the calcium is combined by phosphoric 

 acid, which probably is derived from the cartilage cells, possibly 

 through autolysis of the nucleoproteins or some similar process.-- 

 Grandis and Mainini,-^ by using mierochemical methods, thought that 

 thej^ found evidence that the phosphorus of ossifying cartilage is 

 converted from an organic combination into an inorganic form 

 (PoOJ, which then takes up calcium from the blood. The methods 

 used have been questioned, and Pacchioni,-* from his studies, was in- 

 clined to the opinion that the calcium entered the cartilage already 

 combined as phosphate. Wells implanted into the abdominal cavity of 

 rabbits various tissues that had been killed and sterilized by boil- 

 ing, and found that tissues rich in nucleoproteins showed no tendency 

 to take up calcium in greater amounts than did tissues poor in nucleo- 

 proteins, which result speaks against the idea that phosphoric acid 

 derived from nucleic acid combines the calcium. On the other hand, 

 implanted dead cartilage soon became thoroughly impregimted with 

 calcium salts, which seemed to be deposited in the same proportion 

 as to carbonate and phosphate as in bone. 



Physical Absorption of Calcium Salts. — As there could be no 

 question of "vital activity" on the part of this boiled cartilage, it 

 seems most probable that there exists in cartilage a specific absoi"p- 

 tion affinity for calcium salts, similar to the absorption affinity that 

 ITof meister -^ observed exhibited by other organic colloids (gelatin 

 disks) toward various crystalline substances in solution. It is of sig- 

 nificance that the substances in which calcium is deposited are, in 

 most instances, of similar character, being homogeneous and often 

 hyaline, although of the most varied chemical composition; in other 

 words, they agree much more in physical tlian in chonical stnicture. 

 Also we find tliat liyalino tissues witli an affinity for calcium often 

 exhibit a similar affinity for othei- substances, such as pigment and 



'.iiii Dyps tliat stain the bones \\\wn fed to livinji: animals (madder) also stain 

 patholof^ical calcific deposits (Macklin, Anal, rvccord. 1!)17 (11). 387). 



22 TTanes, who observed that the phosphatids disappear from tlie liver of the 

 developing chick, supfjests this as a source of the iijiosphoric acid rcijuired for 

 ossification (Jour. Exper. ]\led., 1012 (10), 512). 



23 Arch, per la sci. ]\Ted. Torino, 1000 (24), 07. 

 2'» Jahrb. f. Kinderheilk., 1002 (56). 327. 



2.'. Arch, exper. Path. n. Pharm., 1801 (28), 210 



