The plan of the central nervous system : a thesis for the degree of Doctor of Medicine in the University of Cambridge / by Alex. Hill.

Alexander Hill

Date:: 1885

Credit: The plan of the central nervous system : a thesis for the degree of Doctor of Medicine in the University of Cambridge / by Alex. Hill. 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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$the lower free border of its cortex. That a functional continuity exists, I have proved by examining the brain of a porpoise (Phocsena vulgaris, kindly placed at my disposal by Mr Clark). In this animal no olfactory nerve is developed, no pyriform lobe, no hippocampus major, and but a rudimentary fornix. Indeed the fornix proper cannot be said to exist, for the part developed contains merely the longitudinal commis- sural fibres which, in addition to its olfactory elements, belong to this structure. As far as I am able to trace them, the fibres contained in the body of the fornix are those denominated by Huxley precommissural. The columna fornicis does not appear to be present. [These and other allied questions however I shall hope to be able to answer as soon as I can obtain a supply of fresh porpoise brains.] The brain of the porpoise is remark- able for the great quantity of commissural fibres which it con- tains as compared with the direct fibres from the crura; the Cingulum for instance is extremely developed. Fig. 13. ■ ■ ■■■■■■■■■■■■■1 ■■ ■ ■ ■ ■ ■ ■■■■■■■■■■■■■1 ■■■■■■■■■■■■■■ ■ ■■ ■ ■■■■■■■■■■■■■■ ■■■■■■■■■■■■■■ ■■■ ■■■ ■■■ ■ ■ ■ ■ ,, ■ ■■■■■■■aiBl'liai ■■■■■■■■■■■■■I ■ ■■■■■ n ;■:! ! K ■ ■■ u ■■ ■■■■■■ ■■ ■ ■■■■■■ ■■ ■ ■■ ■■■us ■■■■ ■■■■■■ ■■■■ BiS 'a(>vu SS ■ ■■ ■■ ■■■■■ ■ ■ ■■■■■■j ■■■■■■ ■ ■ ■ ■ ■■■■ ■ ■ ■iii ■ ■■■■ m ■■■■ ■ ■mm ■■■■■■■■■ ■■■■I ■■■ ■■■■B ■■ ■■■■ ■■ ■■■■ ■■ ■Hi ■■ ifH mi ■■■■ ■■ ■■■■■ ■■ ■ ■■■ ■■ ■■■■■ !■■■■ ■■■■ ■■■■ ■■■ ■■■ ■ ■ ■■■■ ■■n ■ ■ ■ ■ ■ ■ 7/1 i //ijiict^fs O.K 8i 05. JPorpoise O oj. In fig. 13 I have represented, for the sake of comparison, the actual size of the body of the fornix as found in the brains of an ox and of a porpoise. The former brain weighed %\ ounces, the latter 9. When the posterior pillar is traced back to the hippocampus, the comparison is still more instructive. I have not, however, as yet succeeded in obtaining the brain of a porpoise in sufiiciently good condition for close microscopic study, and will not therefore at present enter into particulars$