Literary Notices. xxvii 



undergo full development until they are united to the central end of 

 the nerve." 



Fleming, from observations made on paraffin sections of nerves 

 stained by the Stroebe method, has convinced himself that the peri- 

 pheral regeneration theory is correct, although he is not willing to dis- 

 card entirely the central theory. He describes three of a series of ex- 

 periments made on rabbits in which the animals were killed zo, 68 

 105 days after complete section of the nerve. In the first (20 days) 

 there was no evidence of regeneration, in the second and third there 

 was very marked evidence of regeneration in the peripheral segment. 

 Regeneration from the central end was prevented by ligaturing the 

 central end. In his preparations, regeneration in the central end was 

 much more marked than in the peripheral end, "which strongly sup- 

 ports the probability that the central end or old axis-cylinder greatly 

 aids in the process of regeneration." The paper further contains a 

 general statement of the pathologic changes which characterize peri- 

 pheral neuritis with findings of the appearances presented by the peri- 

 pheral nerves when stained by the Stroebe method. The reports of 

 the cases given do not admit of abstraction. In certain of the four 

 cases presented and in other cases the study of which was not com- 

 pleted at the time the report was made, peripheral or neuroblastic re- 

 generation was observed, more marked in some of the cases than in 

 others. 



The observations recorded in the paper bear evidence of being 

 based on very careful experimental work and on an extended study of 

 autopsy material. It may be permissible, however, to call attention to 

 certain statements made in the above report which need further eluci- 

 dation before they may be accepted as fully established. The state- 

 ment is made that as a result of the proliferation of the nuclei of the 

 neurilemma of the degenerating peripheral end of the nerve, young 

 neurilemma cells are formed possessing large oval nuclei and granular 

 protoplasm, "which become arranged in more or less regular columns 

 and begin to act as neuroblasts." Neuroblasts, as is well known, are 

 of ectodermal origin while the neurilemma sheaths with their nuclei are 

 developed from cells of mesenchymal origin (Gurwitsch). If the per- 

 ipheral regeneration theory is accepted, we are forced to the conclu- 

 sion that, while in normal development the neuraxes of neurons are de- 

 veloped from cells of ectodermal origin, during the process of regener- 

 ation of peripheral nerve fibers degenerated as a result of section or as 

 a result of changes produced by toxic agents, the neuraxes or axis-cyl- 

 inders develop from cells of mesenchymal origin, which, after having 



