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XIII. On certain Functions of the Spinal Chord, with further Investigations into its 
Structure. By J. Lockhart Clarke, Esq. Communicated hy Sap*iuel Solly, 
Esq., F.R.S. 
Received April 6, — Read April 14, 1853. 
TV^HEN I had the honour of laying before the Royal Society my former researches 
on the structure of the spinal chord, I intimated an intention of preparing another 
communication on the structure of the medulla oblongata and cerebellum ; but as 
many important points in the minute anatomy of the chord still remained in obscurity, 
I thought it advisable to make them first the subject of special inquiry, as far as the 
new method I employed would enable me to proceed. Moreover, as all investiga- 
tions into the structure of any organ have, or ought to have, for their object a clearer 
and better knowledge of its functions, I have undertaken also to communicate in 
this paper whatever physiological deductions may appear to follow from my observa- 
tions. Having no particular theory to support, and being influenced in these inquiries 
by no other feeling than the simple desire to elicit truth, the greatest care has been 
taken to verify my facts, and caution has been exercised in drawing conclusions from 
them. 
It is a question of great interest and physiological importance, whether the roots 
of the spinal nerves belong exclusively to the spinal chord, or whether part of them 
ascend within either the white or the grey columns, and form the channels by which 
impressions are transmitted to and from the brain. On account of its interest and 
importance, I have employed much time and labour in endeavouring to arrive at 
some well-grounded and settled conclusion on this very difficult subject, having 
devoted to it alone many hours daily for nearly five months. So extremely intricate, 
however, is the internal structure of the chord ; so numerous are the planes in which 
the nerve-roots enter the grey substance ; and so various are the directions which 
they pursue within it, that notwithstanding the perfect transparency of my prepara- 
tions, and the sharp outline which their fibres retain, my efforts to determine the 
exact relation between these roots and the white and grey columns appeat’ed for 
some time almost hopeless ; but by varying my dissections according to the exigencies 
of each case of difficulty, I succeeded in arriving at several results which I believe 
will be considered important. 
That part of the fibres composing the anterior and posterior roots of the spinal 
nerves ascend longitudinally with the white columns, without entering the grey sub- 
stance of the chord, and transmit to and from the brain impressions which give rise 
