148 STRUCTURE OF THE NERVOUS SYSTEM, BY MAX SCHULTZE. 



with powers effecting an apparent enlargement of from 500 to 

 800 linear. They are moderately frequent in the central organs 

 and in the neighbourhood of the peripheric terminations. In 

 such fibres as these no internal structure can be detected by 

 the microscope. Their nervous nature is, however, placed 

 beyond the possibility of question by their connection with 



Fig. 17. 



Fig. 17. Primitive nerve fibrils, a, from the nervous fibre layer of 

 the retina ; b, from the external granule layer of the retina, showing 

 at x a larger varicosity, resulting from imbibition ; c, from the olfac- 

 tory groove of the Pike, showing a thick nerve fibre enclosed in a 

 sheath, breaking up into fibrillee. 



ganglionic cells, and by the evidence of their issuing from 

 thicker nerve fibres. When fresh, it is very difficult to isolate 

 them, but this may readily be effected in preparations that 

 have been carefully hardened. On treating the fibrils with 

 watery solutions of different salts in certain degrees of concen- 

 tration, and with solutions of chromic and perosmic acids, 

 besides being hardened, they undergo during the first few hours 

 a process of partial imbibition, occasioning the appearance of 



