No. 3.] PERIPHERAL NERVES. 705 



way towards the periphery into the completely degenerated 

 part of the fibre, ending free in the protoplasm ; ten nuclei of 

 the sheath are seen in this short segment. In the layer of 

 connective tissue found between the central ulnar and implanted 

 segment are to be seen a few very fine threads stained deeply 

 blue, surrounded by a thin layer of a pale blue color. They 

 are found between the connective tissue fibrillae and cellular 

 elements constituting the layer just mentioned. I was often 

 able to trace them through several fields of the microscope 

 when studied with a yV inch oil immersion, but found no 

 example where I could observe their connection with one of 

 the fibres of the central end. In order to see these fine new 

 axis cylinders clearly, for that is what they undoubtedly are, it 

 is necessary to cut very thin sections, 5 to 7 mikrons in 

 thickness ; and, as their course is always somewhat irregular, 

 one can easily see that a section, embracing a portion of the 

 central nerve fibre and a young axis cylinder in connection 

 with it, as it winds its way through the developing connective 

 tissue for a distance of about ^ ctm., would be exceedingly 

 rare. Stroebe was able to see such a connection. We find 

 on p. 208 of his article the following statement: " Nicht 

 selten treten jedoch auch Beziehungen der schmalen Axen- 

 cylinderin der Druckstelle zu jenen mit kolbiger Endanschwel- 

 lung versehenen Axencylindern des centralen Stumpfes auf, 

 welche bei den friiheren Stadien beschrieben wurden (see PI. 

 VII, Fig. I, 2, and 3. bei K. A. of his article). Man sieht die 

 junge Faser sich vom alten Axencylinder centralwarts von 

 dessen terminaler Verdickung dort, wo der Axencylinder, abge- 

 sehen von geringer Ausschwellung, wieder normal ist, abzwei- 

 gen, dann in der alten Scheide weiter peripherwarts ziehen und 

 so zwischen die Zellziige der Compressionsstelle eintreten." 

 Stroebe used rabbits in his experiments, compressing the 

 "large ear-nerve" with an instrument constructed by him. 

 The observations above recorded were made on nerves removed 

 from the rabbit seven days after compression, hardened in 

 Miiller's fluid, and stained in anilin blue safranin. Even after 

 the most careful search in longitudinal and cross-sections, and 

 teased preparations made from the implanted portion (Exps. 



