— 47 — 
Regarding the origin of the nerve-tubes, Hermann's opinion is, 
that a direct origin from ganglion cells is very rare, as a rule they 
have an indirect origin, and are formed of fibrillæ originating in 3 
different ways: 
1) from ganglion cells, »Diese Fibrillen sind aber niclit, wie 
etwa vermuthet werden konte, direkte Auslåufer der Ganglienzellen, 
sondern entspringen stets von einem KnotenpunMe« (1. c. p. 85). 
On a careful examination of sections this is easily seen. »Die vom 
Zellvortsatz abzweigende Theil-Fibrille« generally penetrates to the 
middle of the fibrous mass of the ganglion. Here it unites with 
»Fasern anderer Herkunft« in a >^Knotenpunkt, von dem aus erst 
die Fibrille in die Bahn der Nervenwurzel, oft unmittelbar neben 
dem Zellfortsatz, riicklåufig iibergeht.« 
2) from fibrils of the longitudinal commissures, in such manner 
that a part of these »in Knotenpunkten endet, von denen andere 
Fibrillen entspringen, um zur Nervenwurzel zu ziehen.« 
3) and finally directly from fibrils of the longitudinal commissures, 
without their passing through any »Knotenpunkte«.^) 
In some cases Hermann has been able to detect a direct origin 
of dorsal tubes of the longitudinal commissures in ganglion cells, 
the mode in which these tubes terminate he has, however, not been 
able to decide. Further, he has stated the mutual interpassage of 
the processes of ganglion cells from one side into the nerves of 
the other side etc. 
Besides what is above quoted Hermann has described a great 
many interesting particulars regarding the minute inner structure, 
which, however, it would occupy too much space to mention here. 
It seems, however, as if later writers have paid much too little 
attention to these exellent investigations, which, indeed, contain an 
amount of persevering accuracy, which can not be too highly 
estimated, and which in my opinion a great many subsequent writ- 
ers have rather failed in affording.^) 
DiETL (1876, 77 and 78) describes the central mass which he 
calls »Marksubstanz« as »ein goberes oder feineres, unentwirrbares 
Netzwerk feinster Fibrillen «. The fibrillæ principally originate in the 
processes of the ganglion cells. »Die Auslåufer der Ganglienzellen 
(des Gehirns) tauchen in die Marksubstanz ein bilden hier eine reiche 
Zerfaserung zum grossten Theile das Substrat derselben und schliess- 
M My view of Hermann's »Knotenpunkte« and fibrillæ will be seen from the 
description of my investigations on that subject. 
The report of Hermann's memoir given by Vignal (1. c, p. 297 — 298) is, 
in several respects, quite incorrect and misleading. 
