12 THE PRESENT CONDITION 



suppose we go to work upon these several parts — flesh 

 and hair, and skin and bone, and lay open these vari- 

 ous organs with our scalpels, and examine them by 

 means of our magnifying-glasses, and see what we can 

 make of them. "We shall iind that the flesh is made 

 up of bundles of strong fibres. The brain and nerves, 

 too, we shall find, are made up of fibres, and these 

 queer-looking things that are called ganglionic cor- 

 puscles. If we take a slice of the bone and examine 

 it, we shall find that it is very like this diagram of a 

 section of the bone of an' ostrich, though differing, of 

 course, in some details ; and if we take any part what- 

 soever of the tissue, and examine it, we shall find it 

 all has a minute structure, visible only under the 

 microscope. All these parts constitute microscopic 

 anatomy or 'Histology.' These parts are constantly 

 being changed ; every part is constantly growing, de- 

 caying, and being replaced during the life of the animal. 

 The tissue is constantly replaced by new material ; and 

 if you go back to the young state of the tissue in the 

 case of muscle, or in the case of skin, or any of the 

 organs I have mentioned, you will find that they all 

 come under the same condition. Every one of these 

 microscopic filaments and fibres (I now speak merely 

 of the general character of the whole process) — every 

 one of these parts — could be traced down to some 

 modification of a tissue which can be readily divided 

 into little particles of fleshy matter, of that substance 

 which is composed of the chemical ele- 

 ments, carbon, hydrogen, oxygen, and ni- 

 trogen, having such a shape as this (Fig. 

 2). These particles, into which all primi- 

 tive tissues break up, are called cells. FioX 



