MULLENIX: EIGHTH CRANIAL NERVE. 243 
The intracellular rings and the protoplasmic bridges connecting 
them with the axis cylinders which Bielschowsky und Briihl have 
described are unique, having been recorded by no other investigators. 
The observation is interesting, in that it affords a suggestion of histo- 
logical evidence in support of the theory of the synapse between 
neurones, which has been advocated by Sherrington (:06). It has been 
found that nerve conduction in which two or more neurones are in- 
volved is much slower than conduction along an axis cylinder of a 
single neurone. Mislawsky (’95) found that the direction of the 
nervous impulse is reversible in nerve-trunk conduction, whereas in 
reflex-are conduction it is irreversible. ‘These and other physiological 
differences between nerve-trunk conduction and reflex-are conduction 
Sherrington has referred to that part of the arc which lies in the central 
gray, and he has introduced the term synapse to represent those “‘in- 
tercellular barriers’ in the central gray which constitute the nexus 
between neurone and neurone. If the view that the sense cells are 
nervous in character should prove correct, the protoplasmic bridges 
which Bielschowsky und Briihl have described in the periphery might 
be regarded as representing the synapse for which Sherrington adduces 
so much physiological evidence in the spinal cord. ‘The neurones 
involved in audition are so short and other conditions are such as to 
render it impracticable to obtain, in this structure, physiological 
evidence of the kind that Sherrington has obtained by experimentation 
upon spinal nerves. But the confirmation of the existence of the 
protoplasmic bridge would be interesting because it would supplement 
the physiological evidence obtained from other regions. — 
I must say, however, that I do not believe that the existence of 
either the intracellular rings or the protoplasmic bridges can be re- 
garded as established until confirmed by other investigators. My 
preparations furnish no evidence of the existence of the protoplasmic 
bridges, and only slight evidence of intracellular nervous material. 
In conclusion, it may be stated that in so far as Bielschowsky 
preparations may be relied upon as revealing the actual conditions, 
we are justified, in the case of the fishes, in regarding the relation 
between nerve terminals and sense cells as one of contact, and not of 
organic union, and the relation between different axis cylinders as, 
likewise, one of contact rather than continuity. Such preparations 
make it possible to trace nerve courses more completely than do Golgi 
preparations, and there is the additional advantage that neurofibrillae 
are differentiated, as they are by methylene blue. My results bear 
out the conclusions of those investigators who have studied the problem 
