DEGENERATION AND REGENERATION OF NERVES 77 



increases in amount with the multiphcation of the nuclei and 

 the disappearance of the degenerated myehn in nerves after sec- 

 tion, contains numerous small granules and droplets of fatty 

 material. Thus according to Mott, Halliburton and Edmonds 

 ('04), "they (i.e., the nuclei of the neurilemma sheath) multiply, 

 and later appear to share with phagoc>i;es in the removal of the 

 broken up myehn di-oplets." And Schroder ('08), basing his 

 views upon the microscopic observations of Stroebe and Biingner 

 and Schiitte, has the following to say relative to the removal of 

 the myelin clumps: 



In this purely degenerative process (i.e., the early clumping of the 

 myelin) early progressive occurrences interpose themselves. The nu- 

 clei of the sheath of Schwann begin to proliferate already on the second 

 day, according to Stroebe they attain their maximum increase in num- 

 ber through mitosis at about the eighth day; coincident with the pro- 

 liferation of the nuclei protoplasm develops, it shoves itself into the 

 breaches and spaces between the myelin clumps, flows around the 

 clumps, then gathers itself together into a single round or oval, demar- 

 cated, single-, or many-celled structure, within whose interior the 

 clumps of myelin rapidly diminish themselves to fine granules (accord- 

 ing to Biingner and Stroebe). In this way arise frequently granular 

 cells with round cell body and a fine latticed protoplasm in whose 

 meshes the granules lie enclosed. Such elements, from about the fourth 

 week on, are to be found in the lymph spaces around the neighboring 

 vessels. Stroebe and Schiitte mention, that the genesis of thse granu- 

 lar cells has been often incorrectly conceived; with predilection, one 

 has declared them leucocytes or so-called wandering cells and has 

 assumed that they arise from the vessels opened at the point of the 

 primary injury to the nerve, move forward along the nerve sheath and 

 then take up at all places the disintegrated myelin. 



REGENERATION 



Marked multiphcation of the nuclei of the sheath of Schwann 

 at an early stage of degeneration and the resulting embryonic 

 nerve fiber have been constant findings with all those observers 

 who since Waller, have studied degeneration and regeneration 

 of medullated nerves after section. Upon this point there is 

 complete agreement. The interpretation, however, of the sig- 

 nificance of the increased number of nuclei and more particularly 

 of the embryonic nerve fiber has given rise, as is well known, to 

 the most heated controversies, often involving personalties. As 



