28 



observations are in harmony with the earlier studies of His ^) on the 

 myelospougium of the human embryo. 



1 have found a neuroglia syncytium in the brain of the teleost 

 Batrachus, in which the conditions for its study are unusually favorable. 

 A broad zone of the brain wall next to the third ventricle contains 

 so few nerve cells and processes that it affords an unobstructed view 

 of the neuroglia. 



Figures 1 and 2 have been made from camera drawings of sec- 

 tions (6 |fO of an adult brain which had been hardened in Müller's 

 fluid. Nucleated columns or axes of protoplasm extend outward in 

 radial manner from the ventricle. In the ependymal region the columns 



Fig. 1. Neuroglia Syncytium of Batrachus tau. Lateral wall of the third ven- 

 tricle. X 844. 



are expanded and confluent, and are continuous with the internal 

 limiting membrane. Neighboring columns are united at various levels 

 by broader or narrower protoplasmic bridges, as His has shown in 

 his Fig. 2, and by many exceedingly fine filaments. The latter extend 

 from the columns everywhere and join in delicate nets. These slender 

 filaments, which play so important a part in completing the reticulated 

 syncytium, usually escape observation in sections treated by the silver 



1) His, Wilhelm, Zur Geschichte des menschlichen Rückenmarkes 

 und der Nervenwurzeln. Abhandl. math.-phys. Klasse der Königl. Säch- 

 sischen Ges. d. Wissensch., Bd. 13, No. 6, Leipzig 1886. 



