1907.] Localisation of Function in the Lemur’s Brain. 147 
PLATE 3, 
Figs. 1—8.—These are drawings made from the central nervous system of Lemur 9, in 
which the face region was removed. The position of the lesion is indicated by a dotted 
line in fig. 1, which is a drawing of a section through the injured (right) hemisphere. 
The preparations were made by the Marchi method, and degeneration is indicated by 
black lines and dots. Fig. 1 shows degeneration passing by the corpus callosum to the 
opposite hemisphere, by association tracts to adjacent convolutions, and by the internal 
‘capsule to the cerebral peduncle. 
Fig. 2 is a drawing of a section through the left (uninjured) hemisphere, and shows the 
degenerated fibres, reaching the grey matter, which have crossed by the corpus callosum. 
Some few degenerated fibres are seen in the internal capsule. 
Fig. 3 is the mid-brain. Degeneration is seen in the crusta of the peduncle, especially 
in its outer and inner fourths. 
Fig. 4 shows the degenerated fibres in the pyramidal tract of the pons. 
Figs. 5 and 6 show them in the pyramidal tract of the bulb. In figs. 4, 5, and 6 many 
of the degenerated fibres are seen decussating to reach the motor nuclei of cranial nerves. 
Fig. 7, through the upper cervical region of the spinal cord, shows a few degenerated 
fibres in the crossed pyramidal tract of the opposite side. 
Fig. 8, through the cervical eniargement, shows that at this level all degenerated fibres 
have disappeared. 
Fies. 9—16.—A similar series of drawings made from the central nervous system of 
Lemur 8, in which a large portion of the lower limb area was removed. 
Fig. 9 is a section through the injured (right) hemisphere. 
Figs. 10, 11, 12, and 13 show the degenerated fibres in the pyramidal tract at various 
levels in pons and bulb. Decussation of these does not begin until a lower level is 
reached than in the case of Lemur 7 (removal of arm area, see Plate 2). 
Figs. 14, 15, and 16 are drawings of the spinal cord—14 at the level of the 8th cervical 
and 15 at the level of the 6th dorsal segment. In fig. 15 the degenerated fibres are nearly 
as numerous as in fig. 14, and also nearly as numerous as in the pyramidal tract of the 
bulb. It is not until the lumbar region is reached that they begin to diminish (fig. 16, 
taken at 5th lumbar level). 
PLATE 4. 
This shows the two types of motor cortex described in the text. Fig. 1 is the first type 
of motor cortex, characterised by giant pyramids (Betz cells), and found in the limb and 
trunk areas. Fig. 2 is the second type of motor cortex with smaller Betz cells, found in 
the face, ear, and eye regions. Higher power views of typical cells from each layer are 
placed by the side of the low power drawings. Methylene blue preparations. 
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