520 
PROFESSORS D. FERRIER AND G. F. YEO ON THE EFFECTS OF 
“ The other lobes are not encroached on by the injury, nor is the internal surface of 
the hemisphere, although, as will be explained presently, it is probable that by an 
undermining process of secondary nature, a portion of the marginal convolution mav 
have been cut off from continuity with the central parts of the cerebrum.” 
The area of destruction was covered by adherent dura mater, under which was a 
secondary cavity, but the whole lesion was external to the central ganglia. 
Microscopical sections of the brain demonstrated the existence of secondary degene¬ 
ration in the left internal capsule, in the foot of the crus cerebri, anterior pyramid, and 
at the upper part of the cervical cord, in both pyramidal tracts. 
In the lower cervical, dorsal, and lumbar regions of the cord, sections by Dr. Ferrier 
(Plate 25, figs. 53, 54, 55) demonstrated the existence of secondary degeneration only 
in the pyramidal tract of the right side of the cord. Slight contraction and con¬ 
sequent distortion had also occurred here as in the previous case—Experiment 17*, 
but the changes were much less marked, probably due to the relatively much shorter 
period that had elapsed between the lesion and death. 
Remarks .—The lesion in this case implicated the whole of the so-called motor area 
more or less, the centres for the leg and face being only partially destroyed. As a 
result there was motor hemiplegia of the opposite side, with temporary conjugate 
deviation of the head and eyes, partial facial paralysis, and incomplete paralysis of 
the leg. 
The hemiplegia was of a permanent character, as was evidenced by the commencing 
contracture or late rigidity, and the demonstration of secondary degeneration in the 
pyramidal tracts. The animal, except for the right hemiplegia, was in other respects 
perfectly normal. There was no affection of the special senses, and there was no 
discoverable impairment of sensation in the paralysed limbs to touch, or any form 
of painful stimulation, heat, pinching, &c. 
General Results. 
These experiments show that destructive lesions of the cortical areas, irritation of 
which by electrical stimuli causes definite movements on the opposite side, cause 
motor paralysis without loss of sensation, limited (monoplegia), or general (hemi¬ 
plegia), according to the position and extent of the lesion. The degree of paralysis 
varies with the completeness of destruction of the grey matter of the respective 
centres. It is further seen that destructive lesions limited to the cortex and sub¬ 
jacent medullary fibres of the Rolandic zone give rise to secondary degeneration 
(sclerosis) of the pyramidal tract, traceable from the seat of lesion in the internal 
capsule, crus cerebri, and anterior pyramid of the same side, and in the postero-lateral 
or pyramidal tract in the opposite side of the spinal cord. 
