ARTICULATIONS OF THE BONES. 117 

Water, z a 80.46 98.3 
Fibrous matter, — - : 11.86 
Albumen, = 2 4.52 38 
Gelatine and Mucilage, - 93 
Muriate of Soda, —- = 1.75 23 
Soda, £ : TL a trace. 
Phosphate of lime, - 70 = 
100.00 99.99 
Margueron*, J. Davy +-. 
Besides the sheath formed by the continuation of the pe- 
riosteum, and which is too slender to retain the bones in 
their proper place, the jomts are furnished with Zigaments. 
These are membranes of a dense fibrous texture, flexible, 
elastic, and possessed of great tenacity. They have their 
insertion in the periosteum and bone, with which they are 
intimately united. When they follow the course of the pe- 
riosteum, and form a sheath round the jot, they are term- 
ed capsular. When they occur as broad belts on the sides 
of the joint, they are called lateral; and when they pass 
from one articular surface, like a cord, into the other, they 
are called central, Their composition has not been investi- 
gated with care. It is probable that they approach the 
nature of cartilage. They serve to secure the joints from 
dislocation—an accident that can scarcely happen, unless 
the ligaments be previously lacerated. They likewise, in 
some cases, furnish a basis for the origin or insertion of 
muscles. 
The motions which joints of the kind are capable 
of performing, may be reduced to three kinds—flex- 
ion, twisting, and sliding. In flexion, the free extre- 
mity of the bone which is moved, approaches the bone 

* Annales de Chimie, xiv. 127. 
++ Mowro’s Outlines of Anatomy, i. p. 82. 
