v] 



LATER PROGRESS 



139 



it next becomes a " colony " of nearly similar cells, 

 and then an obvious second-grade individual, with 



(e) 



(c) (b) (a) 



Fig. 14. Five stages in the early development of a nerve-cell from 

 the brain. In (a) the rudiment of the nerve-fibre is seen. In 

 (c) the dendrite with its branching processes has become obvious. 

 (e) does not represent the final stage ; in the adult nerve-cell 

 size and complication are many times greater. (Highly magnified.) 

 (After Kamon Cajal.) 



outer protective and inner nutritive layer. Then 



