On cerebral anatomy : an address delivered at the opening of the Section of Anatomy and Physiology, at the Annual Meeting of the British Medical Association, held in Birmingham, July, 1890 / by D.J. Cunningham.

  • Cunningham, D. J. (Daniel John), 1850-1909.
Date:
[1890]
Catalogue details

Licence: Public Domain Mark

Credit: On cerebral anatomy : an address delivered at the opening of the Section of Anatomy and Physiology, at the Annual Meeting of the British Medical Association, held in Birmingham, July, 1890 / by D.J. Cunningham. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    18 increases with the second, but the interior with the third, power of the radius. From this it is evident, seeing that the proportion of internal white matter and external grey matter is in all cases a uniform one, that in the evolution of a large animal out of a small animal a disproportion between the grey capsule and the white core of the cerebrum must result. This is compensated for by the ex- tended cortex placing itself in folds or puckers, and thereby re- ducing the capacity of the capsule to a degree which brings it into correspondence with the white contents; consequently the formation of the convolutions and furrows is simply the result of the tendency on the part of the superficial layer to increase by surface extension, and of a mutual space accommodation (Raum- accommodation) of the grey substance and of the white conduct- ing paths. It is but right that I should state—although, indeed, Jelgersma appears to be ignorant of the fact—that many years ago Bail- larger arrived at very similar conclusions; and, further, that the theory in question has received independent testimony in its favour at the hands of my colleague, Professor George F. Fitz- gerald. Some months ago, having constantly had occasion to appreciate the unsatisfactory nature of the current explanations as to the origin of the convolutions, I detailed to Professor Fitz- gerald, as far as I could, the conditions of cerebral growth, and asked if he could account for the presence of the cortical furrows upon geometrical principles. The views which he advanced were identical with those of Baillarger and Jelgersma.22 But Jelgersma brings forward some additional facts, which are well worthy of our consideration. He points out that the extent of the cerebral surface depends upon two factors, namely, (1) the absolute quantity of the grey matter, and (2) the thickness with which this is spread over the surface. The absolute quantity of grey matter present is determined by the bulk or by the psychi- cal endowments of the animal, or by both of these factors to- gether. On the other hand, although the thickness of the grey cortex is very much the same in the same species; it differs con- siderably in different animal groups, and it follows from the theory which he has advanced that the more sparsely the grey substance is spread over the surface of the white matter the richer will be the convolution type. In the cetacean cerebrum the grey cortex is exceedingly thin, and it is due to this that the surface shows such an extreme condition of complexity. But there is another way of looking at this question, and it is this: Anything which diminishes the quantity of internal white matter will of necessity tend to increase the folding of the exter- nal grey capsule; and in a short additional paper, published last March, Jelgersma23 discusses in this light the effect produced by total or partial suppression of the corpus callosum on the convo- lutionary type of the cerebrum. The question is a difficult one, because defects in the corpus callosum are very frequently asso- ciated with dilatation of the ventricular system, which of course would compensate fully for any deficiency in the white central core of the hemisphere. A profound convolutionary disturbance accompanies the non- n I am also Informed by Mr. John Marshall, F.H.8.,that the Bame doctrine was taught by Dr. Sharpey In University College, London. ** Das Qehlrn ohne Balken: eln Beltrag zur Wlndungstheorle, Aeurolo-