ORIGIN OF NEURON PATTERN 



183 



The following diagrams will assist in making the 

 point clear. Let ab (Fig. 58) represent a mass of con- 

 tinuous, closely coherent tissue, the cells of which are 



5$ 



+ 



a 



59 



Figs. 58, 59. — Diagrams illustrating electrical polarization of a cell 

 by bioelectric currents: Fig. 58, polarization of first type; Fig. 59, 

 polarization of second type; further explanation in text. 



in contact, such, for example, as the embryonic neural 

 tube. In consequence of differences in physiological 

 condition the region a is electropositive internally to the 

 region b and a current passes through the tissue between 



