506 S. WALTER RANSON 
In the dog which was killed thirty-four days after the removal 
of 1 em. of the sciatic nerve, the distal stump showed proto- 
plasmic bands like those already described except that the drop- 
lets of myelin were smaller and scarcer. A few showed new 
axons within them; but these axons could be followed for long 
distances, were sharply differentiated from the protoplasm of 
the band and were connected with fibers in the sear. No tran- 
sition stages could be seen which might be interpreted as the 
development of axons in situ. More will be said about the 
relation of the new axons to the protoplasmic bands in the last 
section of this paper. 
2. Degeneration of the non-medullated fibers and formation of 
nucleated protoplasmic bands 
So far as we are aware no one has described the degeneration 
of the non-medullated fibers of the spinal nerves. Tuckett 
(96) presents experiments showing that the sympathetic axons 
lose their affinity for methylene blue on the second day after 
separation from their cells of origin. Cajal and others who have 
used the silver method as he directs have apparently been able 
to see these fibers in the spinal nerves only when they were 
undergoing regenerative or degenerative changes and possessed 
an. increased affinity for the silver. Cajal states that he has 
followed the degeneration of the non-medullated fibers during 
the first eight days, but his observations clearly refer only to 
the immediate vicinity of the lesion where the fibers have under- 
gone an abortive regeneration. He states that the centrally 
directed end bulbs (which we will describe in another place) 
and the non-medullated fibers which carry them, stain well 
until the third day, after which they gradually fade out and 
are no longer visible after the sixth or seventh day. ‘These 
statements are correct only when they are made to apply to 
the distal stump within 1 mm. of the cut surface. 
At a distance of 5 mm. from the cut surface one day after 
the operation (Dog x1), many of the non-medullated fibers are 
no longer uniformly stained but are distinctly granular. At 
the end of the second day (Dog x11), the fibers become broken 
