10 /ournal of Comparative Neurology and Psychology. 



to the muscle fiber may be. To investigate this a much higher 

 magnification and a more differential stain are necessary than at 

 present are available in the examination of fresh tissues. 



By means of the orange G acid fuchsin counterstain above 

 referred to, I have found it possible to distinguish clearly be- 

 tween the nerve fiber (blue), the sheath of Henle (rose-pink), 

 the faintly stained neurilemma (pink), and the muscle fiber 

 (orange). In thin sections (5 to 7//) examined by the 1-12 

 Zeiss oil immersion lens, where the meduUated nerve was ob- 

 served to lose its medullary sheath and divide into the primary 

 branches, I often clearly saw the primary branches, especially 

 when they were lying in the upper edge of the muscle fiber, 

 enclosed by the neurilemma and by the sheath of Henle, 

 Moreover these sheaths could at times be traced for some dis- 

 tance on the primary divisions of the ending. The differentia- 

 tion of the two nerve sheaths was at times aided by the fact 

 that one could distinguish the attachment of the neurilemma 

 to the node, as described by Boveri and Bethe, ' while the 

 sheath of Henle had no such attachment but was continuous 

 over the node. This condition was seen in the section from 

 which Fig. 7 was obtained. Here the neurilemma attached 

 itself to the node where the medullary sheath ceased, and thence 

 was continued over the fibrils. For this research it was not 

 necessary to determine whether at the node the neurilemma was 

 or was not interrupted. Outside of this lay the sheath of Henle, 

 Each sheath could be followed separately to the muscle fiber, 

 where together they applied themselves to the sarcolemma. 

 When so applied to the muscle fiber, it was not possi- 

 ble to distinguish with accuracy between the pale 

 stained neurilemma and the strongly stained sheath of 

 Henle. But it was possible to see clearly that the sheath 

 round the nerve was distinct Yrom and was placed outside of the 

 sarcolemma — a distinction which was aided by the fact that 

 here the sheath of Henle stained at times more strongly than it 

 had previously done and appeared as if it were there thickened 



' Bethe : Anatomic und Physiologic dcs Ncrvensystems, 1903, p. 50. 



