MULLENIX: EIGHTH CRANIAL NERVE. 239 
have been described by Dogiel, Szymonowicz, and Kolmer are in 
perfect accord with Apathy’s theory, but they are in no sense irrecon- 
cilable with the neurone theory. Likewise, the free ending of axis 
cylinders, while it seems to be emphasized principally by neuronists, 
is not at all incompatible with the fibrillar theory. ‘lhe confusion in 
the matter seems to result chiefly from the fact of the different points 
of view occupied by the fibrillists and the neuronists. 
The adherents of the neurone theory, upon the basis of important 
anatomical, embryological, and degeneration evidence, look upon the 
ganglion cell, dendrite, and axis cylinder as together constituting the 
structural unit of the nervous system. ‘The existence of the neuro- . 
fibrillae has long been recognized, but modern neuronists regard them 
as constituent parts of larger morphological units (Parker, :00, Collins, 
06). Apdthy and his followers, on the other hand, magnify the 
importance of the neurofibrillae and attach less significance to the more 
complex structure which is known as the neurone. Apathy represents 
the neurofibrillae as structures which maintain their individuality 
in the nerve fibre, losing their identity only in three localities, viz., in 
the neuropile, the ganglion cell, and the innervated organ,— sense 
cell, muscle fibre, or gland cell. He represents the sensory fibrillae as 
anastomosing in the neuropile to form an ‘‘Elementargitter,”’ out of 
which larger fibrillae are assembled, which make their way to muscle 
fibres as motor fibrillae. From this conception Bethe draws the 
deduction that the neurofibrillae of the receptor organs extend without 
interruption to the neuropile, and from there to the motor ganglion 
cell, still without interruption, and are continued in the efferent nerve 
as motor fibrillae which make their way to the terminal organ, still 
without interruption. In other words, Bethe conceives that in the 
neurofibrillae there exists a continuous bridge between receptor and 
motor elements. 
It is not my purpose to undertake a criticism of Apathy’s view, 
further than to remark that, while his conception is in some respects 
very plausible, there is much in it that is extremely hypothetical. 
To assign to the neurofibrillae, exclusively, the power of conducting 
nerve impulses is to make an assumption which is not supported by 
evidence. 
I have given this résumé of Apdthy’s fibrillar theory in order to 
prepare the way for a more critical consideration of the extracellular 
networks and the intracellular nervous structures which have been 
described by Kolmer and by Bielschowsky und Briihl. ‘These in- 
vestigators are agreed in their account of pericellular networks. In 
regard to endocellular nervous structures they differ. 
