v] LATER PROGRESS 137 



is reflected that these lesser individuals were originally 

 all alike and all self-supporting, the modifications 

 which they have undergone are nothing short of 

 amazing, as a glance at any text-book of histology 

 will show. We can but mention a few of the most re- 

 markable. For shape, the ordinary nerve-cell (Fig. 14) 

 is striking enough ; the cell-body is an ordinary, some- 

 what polyhedral mass of protoplasm, but from it are 

 given off branching processes which divide and 

 sub-divide and with their finest sub-divisions come 

 into contact with the branches of other nerve-cells ; 

 and at one point runs out a single thread, the nerve- 

 fibre, which, though its thickness is to be measured 

 in hundredths of an inch, may yet reach a length of 

 several feet before it finds the muscle it is to move 

 or the sense-organ whose message it is to carry. 

 Remarkable in another way are the epithelial cells 

 of our skin, which, continually produced in the deeper 

 layers, undergo a gradual metamorphosis into the 

 thin plates of horny matter called scurf, or scarf-skin ; 

 by their perpetual wearing off and replacement from 

 below, they give us an outer covering which shall be 

 at once pliant and sensitive, of considerable strength, 

 and quick-healing. 



When an individual's only duty is to commit 

 suicide for the good of the society to which he 

 belongs, the process of subordination has gone 

 a very long way. In what are known as syncytial 



