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 < . 
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. — Sternberg 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 - 85 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 
Sodium sulphate 
Sodium chloride 
a hundred 
3 > 
parts of 
ash) 
26-66 
44-81 
6-11 
Sodium phosphate 
Calcium phosphate 
Magnesium phosphate 
)) 
11 
8-42 
7-88 
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 Waanipelmeyer, ibid., Bd. xxxii. S. 550. 
2 Arch. f. Physiol., Leipzig, 1881, S. 105. 
s Arch. f. mikr. Anat., Bonn, Bd. xiv. S. 54. 
4 Ztschr. /. physiol. Chem., Strassburg, Bd. xv. S. 331. 
VOL. I. — 8 
