John Marshall

“ In the human cerebrum, the vertex is extraordinarily high and is placed further back; so that the fall of the outline behind, is necessarily more sudden, and the depth of the posterior region is very characteristic. In the ape again, the shortness and shallowness of the anterior portion makes the curve of that part of the cerebrum more abrupt, and more equal to the hinder curve, than it is in man, in whom the elongated and deep, frontal region produces a much more gradual curvature from the vertex forwards, than exists backwards. ”

“ Comparing these numbers with the area of the internal surface of one of the cerebral hemispheres, in the Chimpanzee's and in the human brain, we find them to be as 1 to 28⋅5 in the ape, and 1 to 12⋅5 in man; so that the corpus callosum is more than twice as large, proportionally to the size of the brain, in man, as it is in the Chimpanzee. We may add, that the corpus callosum in our specimen is exactly of the same length as in Schroeder van der Kolk's figure, whilst the brain itself is a little longer. As in man, the corpus callosum of the ape, is thickest behind. ”

“ The multiplication of accurate data on such a subject is, however, most desirable, and in the face of the very different statements just now made, as to matters of fact, in the anatomy of the Simian brain, new materials for consideration cannot but be welcome to all parties. ”

“ It is desirable that many more observations on the weights of these separate parts of the encephalon in the several races of men, and in animals, as compared with their bodies, should be collected: they would yield neater results than those arising from measurements, for reasons which will presently be abundantly illustrated. ”

“ From its small size, and from the imperfect development of the convolutions, this brain was, most likely, taken from a very young animal; the cerebral membranes have been removed; the vertex is somewhat flattened; the orbital surfaces have lost their characteristic concavity; the middle lobes have sunk asunder; and the cerebellum has, undoubtedly, been a little displaced backwards. ”

“ The habenulæ were distinct. The pituitary body was large, and wider than deep. The corpora albicantia were beautifully seen, quite distinct from each other, and connected, as in man, with the anterior pillars of the fornix. ”

“ But much as this, unusually heavy, young Simian brain raises previous estimated ratios, it still remains far below the human proportion, taken at a corresponding age. In Huschke's case of the child of six years, the ratio was 1 to 11; and the proportion in the human adult, is usually given as 1 to 36, or as 1 to 40, in cases of persons killed or dying suddenly, whilst the body is in a healthy state. ”