1230 



reckon them to belong to the same class of the so-called "accessory" 

 innervation apparatus of the cross-striated muscle-fibres. 



These nerve-tibres and their endorgans on the voluntary muscle- 

 fibres, described above, cannot well be otherwise ihan of a sympa- 

 thetic nature. Non-medullated nerve-fibres in general take a longer 

 time to degenerate after section of the nerve than do the meduliated 

 fibres and their end-organs. Whilst as a rule 3 or 4 days after 

 dissection of the nerves all the motor nerve-endorgans on the muscle 

 fibres have disappeared, it is possible to find here and there in the 

 sections seemingly intact non-mcdullated nerve fibres as long as 14 

 days after dissection of tiie nerves. But when we give the nerve- 

 fibres, as was done in the ex[)eriment'*described above, a month to 

 degenerate in, before the animal is killed, we are sure to find all 

 the dissected nerve-fibres, meduliated and non-medullated degeneiated. 

 So when, after the lapse of a monti), we kill the animal, and when 

 we then find in the sections intact nerve-fibres, cleaily and sharply 

 outlined, which take the neurofibrillar stain readily, and are found 

 ending in beautifully-stained regular endrings and endnets, we are 

 justified to draw the conclusion, that these nerve-fibres were not 

 cut through when the nerves were dissected. It follows from the 

 description of the experin)enf, that these intact nerve-fibres must be 

 fibres which enter the nerves after the ganglion spinale has been 

 passed, and whose trophic centre, the gauglioncell, lies outside the 

 medulla spinalis and outside the ganglion spinale, viz. sympathetic 

 nerve-fibres, dei'ived from ganglion-cells lying in the ganglia of the 

 sympathetic chain. 



So oui' experiment has given convincing evidence for the exactness 

 of the conclusion, drawn by one of us (Bokke, 19J1, 1916) from 

 his former observations. 



it is proved by the results of our experiment, at least for the 

 muscles of the trunk, not only that the accessory fibres and their 

 end-orqans belong to the sym])nthetic system, but also, that they are 

 sympathetic elements ivith a centrifugal, efferent trans- 

 mission of nerve impulsrs. 



In the communication by Dr. Agduhr, appearing in this same 

 number of the Proceedings, it will be shown, that the identical con- 

 clusion may be drawn for the muscles of the extremities. 



Leiden, _ ._,^ 



y, . January j9J9. 

 Utrecht, '^ 



