526 TISSUES OF THE CONNECTIVE SUBSTANCE. 



III. BONE. 



The bony structure proper, when free from other formations occurring 

 in bones, such as marrow, nerves, and blood-vessels, consists of cells and 

 a matrix. 



The cells have not been closely studied in regard to their chemical 

 constitution. On boiling with water they yield no gelatin. They 

 contain no keratin, which is not usually present in the bony structure 

 (HERBERT SMITH *). 



The matrix of the bony structure contains two chief constituents, 

 namely, an organic substance, and the so-called bone-earths, lime-salts, 

 inclosed in or combined with it. If bones are treated with dilute hydro- 

 chloric acid at the ordinary temperature, the lime-salts are dissolved 

 and the organic substance remains as an elastic mass, preserving the shape 

 of the bone. 



The organic matrix consists chiefly of ossein, which is generally 

 considered as identical with the collagen of the connective tissue. It 

 also contains, as HAWK and GIES 2 have shown, mucoid and albuminoid. 

 After the removal of the lime-salts by hydrochloric acid of 2-5 p. m. 

 these experimenters were able to extract the mucoid by one-half sat- 

 urated lime-water and to precipitate it with 2 p. m. hydrochloric acid. 

 After the removal of the osseomucoid and collagen (by boiling with 

 water) they obtained the albuminoid as an insoluble residue. 



The osseomucoid on boiling with hydrochloric acid yielded a reduc- 

 ing substance and sulphuric acid, 1.11 per cent sulphur appearing in 

 this form. The osseomucoid stands close to the chondro- and tendon 

 mucoid in elementary composition, as may be seen from the following 

 analyses : 



C H N S O 



Osseomucoid 47.43 6.63 12.22 2.32 31 .40 (HAWK and GIES) 



Chondromucoid. . .. 47.30 6.42 12.58 2.42 31 . 28 (C. MORNER) 



Tendon mucoid. ... 48.76 6.53 11.75 2.33 30.60 (CHITTENDEN and GIES) 



Corneal mucoid. ... 50.16 6.97 12.79 2.07 28.01 (C. MORNER) 



The osseoalbuminoid is insoluble in 2 p. m. hydrochloric acid and in 

 5 p.m. Na2C(>3, but dissolves in 10 per cent KOH with the formation of 

 albuminates. The composition of chondro- and osseoalbuminoid is as 

 follows : 



c H N s o 



Osseoalbuminoid 50 . 16 7 . 03 16 . 17 1.18 25 . 46 \ HAWK and 



Chondroalbuminoid . . . 50.46 7.05 14.95 1.86 25.68J GIES 



The inorganic constituents of the bony structure, the so-called bone- 

 earths, which after the complete calcination of the organic substance 

 remain as a white brittle mass, consist chiefly of calcium and phosphoric 



1 Zeitschr. f. Biologie, 19. 2 Amer. Journ. of Physiol., 5 and 7. 



