CARTILAGE. 113 



but little, and are proportional to each other ; the amounts of magnesia 

 and carbonic anhydride are also proportional the one to the other. 

 The amount of potash is greater than that of soda. The amount of 

 chlorine is very small, and is greater in the teeth (0*21 per cent.) than 

 in bone. Fluorine is a minimal constituent of both 1 ; as a rule, not 

 more than 0*05 per cent, is present. 



Water is present in two forms ; one part passing off at 300-350 C. 

 is similar to water of crystallisation ; the other part is only expelled by 

 fusion with silicic acid, and is an expression of the basicity of the 

 phosphate, and is called water of constitution or acidic water. 



The composition of the ash finds its simplest expression in the 

 formula, Ca 3 (P0 4 ) 2 +Ca 5 HP 3 13 +Aq, in which 2 to 3 per cent, of 

 the lime is replaced by magnesia, potash, and soda, and 4 to 6 per cent, 

 of the phosphoric acid by carbonic anhydride, chlorine, and fluorine. 

 The limit of variation is, however, small, and the differences between 

 bone ash and tooth ash are not greater than those between the ash of 

 different bones. 



The notochord. Steinberg 2 found that neither gelatin nor chondrin 

 is obtainable from the notochord, and Neumann 3 that the cells stain 

 with iodine as though they contained glycogen. Kossel 4 obtained a con- 

 siderable supply of material from large lampreys, and found that it 

 contains 95-96 per cent, of water ; this contrasts strongly with cartilage, 

 and corresponds with what one finds in other embryonic tissues. The 

 amount of ash is O85 per cent. The amount of glycogen constitutes 

 from 12 to 15 per cent, of the solids present; the high percentage of 

 this substance is another feature common to embryonic structures. 

 There is not much more than a trace of proteid matter soluble in water. 

 Gelatin, collagen, and mucin are all absent ; the bulk of the solid matter 

 is an insoluble proteid easily digested by artificial gastric juice ; it yields 

 no sugar on treatment with mineral acids. 



Cartilage. The following analyses by Hoppe-Seyler exhibit the 

 relative proportions of the chemical constituents of human hyaline 

 cartilage. In 1000 parts 



Costal Cartilage. Articular Cartilage. 



Water 676*6 735'9 



Solids 323-3 264-1 



Organic solids . . 301'3 248'7 



Inorganic solids . . 22'0 15 '4 



Potassium sulphate (in a hundred parts of ash) . 26 '66 

 Sodium sulphate . 44 '81 



Sodium chloride ,, ,, .6*11 



Sodium phosphate ,, . 8*42 



Calcium phosphate ,, 7 '88 



Magnesium phosphate ,, . 4*55 



The organic solids consist in small part of those in the cells, 

 which are of the usual proteid nature, together with small quantities 

 of fat and glycogen, demonstrable by micro-chemical means; but the 



1 For recent estimations of fluorine in bone and teeth by Carnot's method (Compt. rend. 

 Acad. d. sc., Paris, tome cxiv. p. 750), see Gabriel, Ztschr. f. anal. Chem., Wiesbaden, 

 Bd. xxxi. S. 522 ; and Waampelmeyer, ibid., Bd. xxxii. S. 550. 



*Arch.f. PhysioL, Leipzig, 1881, S. 105. 



3 Arch. f. mikr. Anat., Bonn, Bd. xiv. S. 54. 



4 Ztschr. f. physiol. Chem., Strassburg, Bd. xv. S. 331. 



VOL. I. 8 



