1285 
corresponding results. When we examine such a cross-section in a 
successful experiment (and only those are considered), we find all the 
sections of the branches of the n. lingualis filled with regenerating 
nerve-fibers, whilst those of the n. hypoglossus are entirely (or nearly 
so) devoid of them, showing only the so-called bands of Binenrr 
of the degenerated nerve-tubes. 
This is — and that gives us the answer to the question mentioned 
above, why no physiological regeneration is to be found — not only 
the case with the larger branches, but also the smaller and smallest 
branches present the same aspect. When the larger branches of the 
hypoglossus are devoid of regenerating axons, no trace of these is 
to be found even in the smallest branches of the hypoglossus, whilst 
even the smallest branches of the lingualis are full of regenerating 
axons, and a dense plexus of regenerated nerve-fibers is present in 
the mucous membrane of the tongue, in the connective tissue of 
the submucosa, but not a single motor nerve-plate is to be found 
on any of the muscle-fibers, in sharp contrast to what we find after 
the regeneration of the nerve-fibers of the hypoglossus into the 
peripheral end of the hypoglossus itself (group a), where we find 
everywhere the regenerating end-plates on the muscle-fibers. 
When regenerating nerve-fibers have penetrated into the old channel 
of a peripheral degenerated nerve, it clearly is impossible for them 
to get out of it and they are compelied to travel it to the end. 
Nowhere is this rule demonstrated so clearly as it is done here. 
The branches of the lingualis nerve wind their way towards the 
final station, the mucous membrane, between the bundles of muscle- 
fibers, and often seem to come into close contact with them, as is 
clearly shown by the examination of the sections in the experiments 
of group a. And yet not a single nerve-fiber of the regenerating 
hvpoglossus nerve leaves the channel of the lingualis in group } 
to form an endorgan on the muscle fibers as it is to be seen every- 
where in the experiments of group «*). 
Now the question might be asked, whether these regenerating 
nerve fibres growing into the peripheral end of the nervus lingualis 
are in reality hypoglossus fibres, and whether it is not more probable 
that the ingrowing fibres are after all lingualis fibres, which grew 
out from the central end of the lingualis and have found their way 
into the old nerve channel. To exclude this source of errors, in a 
number of animals, in which 3 and 4 months ago the central end 
of the n. hypoglossus had been joined to the peripheral end of the 
1) J. Boeke, Ueber De- und Regeneration motorischer Endplatten, ete in Verhandl. 
der Anat. Gesellsch. Versamml. in München. April 1912. S. 152 
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Procecdings Royal Acad. Amsterdam Vol. XV. 
