1910-11.] Independence of Peripheral Sensory Neurons. 349 
XXI.— The Independence of Peripheral Sensory Neurons in view 
of the Results of Experimental Section of the Optic Nerve 
in the Rabbit. By Janie Hamilton MTlroy, M.A., B.Sc., M.B., 
Ch.B., Barbour Research Scholar in Physiology. (From the Physio- 
logical Laboratory, University of Glasgow.) Communicated by 
Professor Noel Paton. 
(MS. received February 24, 1911. Bead January 23, 1911.) 
[Short abstract of a paper which will appear in extenso in “ Brain .” ] 
The problem of the amount of independence possessed by the units which 
go to make up the nervous system is one which has long occupied the 
attention of neuro-pathologists, and is still far from solved. That degener- 
ative changes, as the result of peripheral injury, may extend across several 
intermediate neurons is indicated by the work of many investigators, 
notably v. Monakow, Campbell, Bolton, etc. Thus after enucleation of 
the eyeball changes have been met with in the visual cortex, show- 
ing that degeneration has travelled over the neurons situated at the 
basal ganglia of the cerebrum to the neurons in the visual cortex itself. 
Interruption of the sensory conduction path affects the integrity of the 
more centrally placed neurons. The question of the stability of the 
peripheral neurons under similar conditions has not received attention. 
Birch-Hirschfeld in 1900 published the results of a large series of experi- 
ments upon the retina, including a few cases of the effects of experimental! 
section of the optic nerve. He examined the retina, by the Nissl method, 
55 hours, 5, 10, and 15 days after section of the nerve, and found definite 
changes both in the ganglion cells and in the nuclear layers. The number 
of these experiments, however, is too small to be convincing. As no other 
definite evidence could be found, it was decided that more extensive 
investigation would be profitable. 
The peripheral sensory neuron as it exists in the eye, ear, nose, and 
skin is well adapted for experimental research, and the eye especially 
offers likelihood of satisfactory results. The optic nerve is accessible for 
operation, and the retina is an organ which can be 'quickly and easily 
preserved for histological purposes. 
