LESION OF DIFFERENT REGIONS OF THE CEREBRAL HEMISPHERES. 495 
A horizontal section of the hemisphere at the point of greatest depth of the lesion, 
viz. : at the upper extremity of the superior temporo-sphenoidal convolution, showed 
that the lesion involved only the ridges and sulci of the angular gyrus, the stem of 
medullary fibres passing backwards to the occipital lobe being uninjured. The cortex 
of the occipital lobe was intact (Plate 21, fig. 14). 
In the right hemisphere the angular gyrus was also quite obliterated, except a thin 
strip of cortex intervening between the ascending parietal convolution and the upper 
extremity of the superior temporo-sphenoidal convolution, which forms a wedge between 
the two limbs of the angular gyrus (Plate 21, fig. 12). 
The posterior limb of the gyrus which becomes continuous with the middle tem¬ 
poro-sphenoidal convolution retained only some traces of the cortex at the bottom of 
the sulci separating it from the superior temporo-sphenoidal convolution and the 
occipital lobe. 
The convexity of the occipital lobe was slightly eroded superficially from post-mortem 
injury. 
The medullary fibres of the occipital region were seen in horizontal section to be 
altogether intact (Plate 21, fig. 14). 
Remarks .— In this case the angular gyri had been effectually obliterated on both 
sides without injury to the occipital lobes or their medullary connexions. The result 
was total blindness without affection of the other senses or motor powers. The total 
blindness lasted only three days, but vision continued permanently impaired, and 
showed no further signs of improvement during the month in which the animal was 
kept under observation. The condition was one of double amblyopia. 
Experiment 9* (Plate 21, fig. 15). 
In this animal the occipital region was exposed on both sides, and both occipital 
lobes were severed with the galvanic cautery, and scooped out bodily. The line of 
incision in both cases passed between the anterior extremity of the first occipital, and 
the parieto-occipital sulcus. 
The portion removed on the right side weighed 1 ’9 grammes ; that removed on the 
left weighed 2T grammes. 
In half an hour after the operation the animal sat up and wanted to move about, 
but it was kept still, wrapped in a blanket, to prevent risk of haemorrhage. Both 
eyes were open equally, the pupils smallish, and the conjunctival reflex equally distinct 
on both sides. 
For two hours, though it was looking about as if it saw, no definite test of vision 
was made ; but at the end of that time it went and sat down beside the next cage 
and allowed the other Monkeys to handle it, and examine its head. It then, of its 
own accord, went into its own cage and sat down. A piece of apple was thrown into 
the cage, and though it fell a full arm’s length away, the animal, without the slightest 
hesitation, or want of precision, put forth its left hand, picked it up, and ate it. 
