The cerebral lesions in a case of complete acquired colour-blindness / by George Mackay and James Crauford Dunlop.

  • Mackay, George, 1861-1949.
Date:
[1899]
Catalogue details

Licence: Public Domain Mark

Credit: The cerebral lesions in a case of complete acquired colour-blindness / by George Mackay and James Crauford Dunlop. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    to combine these unilateral impressions into a harmonious •picture there must be a further conduction of the stimuli along higher paths of association. Similarly it is quite conceivable that to excite those sensations which we interpret as colour there may be required a conduction of the stimuli out of their first halting-place iii the calcarine into the not distant grey matter of the fusiform before the colour value can be appreciated. Such a theory would accord well with the case before us. ' While a great part of the visual portion of the optic radia- tion has been damaged, the macular fibres have escaped. The eccentric retinal form sense has thus been lost; in the calcarine area central {i.e. macular) sense has been retained. But sup- posing that the fusiform is the seat for the interpretation of chromatic stimuli, the very great destruction which it has undergone in both hemispheres would sufficiently explain the loss of colour-sense by the damage done to all the fibres irt their second flight from the calcarine to the fusiform. In this connection it is of the highest interest to note that in Verrey's ^ case of right hemiachromatopsia (the only one re- corded with subsequent autopsy) there was found an organised haemorrhagic cyst 3| cm. long, i cm, broad, and if cm; deep, situated between the floor of the horn of the left lateral ventricle and the basal surface of the occipital lobe. It occu- pied the white substance of the third occipital convolution ; it destroyed more or less completely the white substance of the occipital end of the lingual and fusiform convolutions, as well as that of the postero-inferior part of the cuneus. Towards the base of the brain it approached the median surface of the occipital lobe without actually penetrating the cortex, and there was at parts softening of the white substance at the side of the cyst. Verrey concluded that the centre for the colour sense will be found in the most inferior part of the occipital lobe, probably in the posterior part of the lingual and fusiform convolutions. The lesion which we have described being of still smaller dimensions carries the prediction a stage further. One swallow does not make a summer, nor can one 1 Arch. d'Ophih., 1888, p. 289.