Volume 1
The physiological anatomy and physiology of man / by Robert Bentley Todd and William Bowman.
- Date:
- 1845-1856
Licence: Public Domain Mark
Credit: The physiological anatomy and physiology of man / by Robert Bentley Todd and William Bowman. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![ami the hippocampi, the pons Varolii ami the cerebellar hemi- spheres. The anatomy of the corpus callosum favours the hypothesis that it is the bond of union to the convoluted surface of the hemispheres, and that it is the medium by which the double organic change is made to correspond with the working of a single mind. There is nothing in the recorded observations of morbid change or congenital defect of this part to militate against this idea; but it must be re- marked that all these cases are accompanied with lesion or defect of other parts, which weaken the inferences to be drawn respecting the corpus callosum. Direct experiments upon this commissure yield only negative results. Longet and others found that irritation of it did not cause convulsions: and Longet states, that injury to the corpus callosum in young rabbits and dogs did not appear to dis- turb voluntary movements; and that, when he incised this l>ody in its whole length in rabbits stauding, they have continued to main- tain that position; or, when urged on, ran; and that no convulsive movement whatever, nor any sign of pain was manifested. Such statements are certainly favourable to the supposition that these fibres are destined to connect centres whose appropriate stimulus is mental. The fibres of the fornix manifest the same insensibility to me- chanical irritants; and their obvious anatomical connexion with particular convolutions warrants but one conclusion, that they associate the actions of those parts. Lallemand relates a case in which the symptoms were altogether limited to mental disturbance, without any affection of the sensitive or motor powers, and the fornix and corpus callosum were found in a state of complete soft- ten ing without discoloration. The fibres of the ]>ons Varolii bring the cerebellar hemispheres into connexion with each other, and with the vesicular matter of the mesocephale. Direct experiments on these fihres can yield no satis- factory result, because they are so intimately associated with the deeper seated parts of the mesocephale, and with the nerves of the fifth pair and others, that it is impossible to irritate them in the living animal without likewise irritating these other parts. And it is sufficiently evident that these fibres have no necessary connexion with sensation and volition, from their non-existence in birds; nor even with the cerebellum when that organ is single. It will be borne in mind, that at a previous page we have referred to the connexion of these fibres with the mesocephale as explaining the crossed in- fluence of lesion of one hemisphere of the cerebellum.](https://iiif.wellcomecollection.org/image/b28043327_0001_0395.jp2/full/800%2C/0/default.jpg)
