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MR. J. L. CLARKE’S RESEARCHES INTO 
behind these latter fibres are sections of thick bundles cut off by them 
from the anterior white columns ; i. Anterior roots of the nerves. 
Fig. 4. Another section of the grey substance nearer the lumbar enlargement ; mag- 
nified 20 diameters. The commencement of the posterior vesicular columns 
kk, is seen at the sides of the spinal canal ; other vesicles are also seen in 
the anterior cornua. 
Fig. 5. A similar section through the lower part of the lumbar enlargement ; magni- 
fied 20 diameiers. The vesicles in the anterior cornua have considerably 
increased in number. 
PLATE XXL 
Fig. 6. A section of the white and grey substance through the middle of the lumbar 
enlargement ; magnified 20 diameters. The posterior vesicular columns kk 
are here situated within the posterior cornua, traversed and surrounded 
by fibres from the posterior roots of the nerves ll, part of which are seen 
also to extend as far as the large groups of vesicles in the anterior cornua. 
PLATE XXII. 
Fig. 7. Outline of a section of the grey substance, through the upper part of the 
lumbar enlargement ; magnified only 10 diameters. 
Fig. 9. A similar section through the lower part of the dorsal region ; magnified 20 
diameters. 
PLATE XXIII. 
Fig. 8. Another section three-quarters of an inch higher up ; magnified 20 diameters. 
Fig. 10. Another section of both the white and grey substance, through the middle oi 
the dorsal region ; magnified 20 diameters. 
Fig. 14. A similar section through the lumbar enlargement, prepared according to 
the second method described in the paper. It represents the course of the 
fibres of the roots of the nerves, and of the transverse commissures, through 
the grey substance ; the vesicles have been omitted to prevent confusion. 
The outline is magnified 20 diameters ; the fibres were drawn under a 
power of 100. Notwithstanding the distinctness of the fibrous arrangement 
here shown, it is to be understood th'at this figure, like the rest, is not 
a scheme, but an exact repi’esentation of one of the preparations which 
accompany the paper, as seen under the microscope. 
