If you take a portion of bone, you will find it easy to strip off from it a membranous sheath or covering; if you examine a joint, you will find both the head and the socket lined with membranes.

The whole of the intestines are enveloped in a fine membrane called _peritoneum_.

All the muscles are enveloped in membranes, and the fasciculi, or bundles and fibres of muscles, have their membranous sheathing.

The brain and spinal cord are enveloped in three membranes; one nearest to themselves, a pure vascular structure, a net-work of blood-vessels; another, a thin serous structure; a third, a strong fibrous structure.

The eyeball is a structure of colloidal humors and membranes, and of nothing else.