REGENERATION OF MEDULLATED NERVES IN THE 

 ABSENCE OF EMBRYONIC NERVE FIBERS, 

 FOLLOWING EXPERIMENTAL NON- 

 TRAUMATIC DEGENERATION 



ELBERT CLARK 



From The Anatoynical Laboratory, University of the Philippines 



THIRTY-TWO FIGURES 



INTRODUCTION 



The present study is based upon experiments in whicli degen- 

 eration and regeneration of medullated nerve fibers were brought 

 about under new experimental conditions. The results obtained 

 relate, for the most part, to phases of the subject upon which 

 the evidence has heretofore been incomplete. In this investi- 

 gation, an experunental obstacle which has been responsible for 

 the strikingly contrary observations between the supporters of 

 auto-regeneration on the one hand and the advocates of an out- 

 growth of the axis cylinder on the other, has been entirely avoided. 

 I refer to an ingrowth of foreign nerve fibers through the scar 

 tissue into a regenerating medullated nerve. This obstacle was 

 avoided by inducing degeneration in the peripheral medullated 

 nerves of the domestic fowl by a prolonged exclusive feeding of 

 polished rice, and subsequent regeneration by a return to an. 

 adequate nutritive diet. 



In 1897 Eijkman first described 'polyneuritis' in fowls which 

 had been kept for three or four weeks on an exclusive diet of 

 polished rice. This has since been confirmed by numerous other 

 investigators and Frazer and Stanton ('11) have noted and illus- 

 trated 'Wallerian degeneration' in the nervus ischiadicus of the 

 domestic fowl which developed paralysis on a pohshed rice^ diet. 



1 White rice, polished rice or decorticated rice is the clear white table rice 

 of commerce. It is rice, which, after having the husk taken off, is further sub- 



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