THE BONY SKELETON, 43° 
PHYSIOLOGY OF THE HUMAN BODY. 
THE Human Bopy is a most skilfully contrived machine, composed of a 
great number of different parts, or organs,! all admirably adapted for the 
work they have to do, or, as it is technically expressed, the functions they 
have to perform. Thus, the limbs, the eyes, the ears, and the nose are 
organs which respectively perform the functions of motion, seeing, hearing, 
and smelling. 
The functions performed by the organs of the body are of two kinds: 
(1) those that have to do with the building up and keeping in repair 
of the body itself; (2) those that bring the individual into connection 
with surrounding objects. The former have been called the functions of 
Nvtrition, or of OrGANIC Lire, and include the digestion of the food, 
with the absorption of the nutritive materials contained in it, the 
circulation of the blood, and respiration; the latter are called the 
functions of Rrenation, or of AntmMaAL Lirr, and include all the forms 
of motion and of sensation. In the following lessons, however, we 
propose to describe first the bony framework, with its covering of muscles 
and skin; then, the apparatus for keeping the whole fit for use; and 
lastly, the nervous system, with the different forms of sensation which 
are the true links of connection between a human being and the outer 
world. 
The Bony Skeleton. 
Bone is a hard substance, composed of two kinds of material, an 
animal matter, called gelatine,? and a mineral or earthy matter, consisting 
principally of lime. To the former it owes its elasticity and toughness, 
and to the latter its hardness. The general appearance of bone is that of 
a network of minute canals, usually running lengthwise, and connected 
here and there by cross branches. Towards the outside, the substance 
of the bone is harder and more compact ; and the whole is covered with 
1 From Greek organon, an instrument, 
2 From Latin gelo, to freeze, because the liquid gelatine takes the consistence of jelly when 
cold. 
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