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XX. Experiments on the Section of the Glossopharyngeal and Hypoglossal Nerves of 
the Frog, and observations of the alterations produced thereby in the Structure 
of their Primitive Fibres. By Augustus Waller, M.D. Communicated by 
Professor Owen, F.R.S. 
Received November 22, 1849, — Read February 21, 1850. 
The object of the present observations is to describe certain alterations which take 
place in the elementary fibres of the nerve after they have been removed from their 
connection with the brain or spinal marrow. 
The following is a brief summary of the opinions and researches of modern physio- 
logists on alterations of the nerve-tubes. 
Burdach* * * § placed a ligature on the sciatic nerve of a frog, and after the lapse of 
a week found no alteration of the primitive fibres either above or below the ligature. 
STEiNRucK-f- did the same, and states that in three cases the whole nerve was more 
slender than on the healthy side, and ascribed it to the atrophy of the neurolema. 
Valentin;]: denies likewise that there is any alteration of the primitive fibres in the 
lower portion of the nerve. 
Gunther and Sch6n§, whose researches are most interesting, state that the primi- 
tive fibres being examined towards the end of a week, after division of the nerve 
when it had lost its irritability, it was perceived that they had no longer the full 
round appearance of the sound ones. Here and there their contents appeared as if 
curdled ; from eight to fourteen days after section these structural changes became 
still more evident, and continued to increase until the fibres appeared fiat, broken 
up, entirely losing their transparency, their contents appearing as if disjointed. 
Nasse II states, that five months after section of the sciatic nerve of a frog, the 
tubes below the section were broken up into granules and small clumps ; that all 
the nerve-tubes were strongly granulated, in some the small granules being united 
into oval bodies, which appeared to be surrounded by a pale cylindrical membrane, 
which in some was wanting, owing probably to its disorganization. 
Having in a former communication to the Royal Society described the nerves of 
the papillae and of the muscular fibre in the frog’s tongue in their normal condition, 
* Beitrag zur Mikroskopischer Anatomie der Nerven, E. Burdach. Konigsberg, 1837, p. 42. 
t De Nervorum Regeneratione. Berolini, 1838, p. 72. 
I De Functionibus Nervor Cerebral, &c. Lib. iv. 1839, p. 127. 
§ Muller’s Archiv, 1840, Versuche und Bemerkungen iiber Regeneration der Nerven, p. 276. 
II Ueber die Veranderungen der Nerven-fasern nach ihrer Durchschneidung, Muller, Arch. 1839, p. 409, 
