Lectures on nervous diseases from the standpoint of cerebral and spinal localization, and the later methods employed in the diagnosis and treatment of these affections / by Ambrose L. Ranney.

Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on nervous diseases from the standpoint of cerebral and spinal localization, and the later methods employed in the diagnosis and treatment of these affections / by Ambrose L. Ranney. 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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    We may start with the statement that the brain consists of two dis- tinct anatomical elements,—hrain ceUs and nerve fihrex. The number of brain cells in the cerebrum alone may be estimated at many thousands. Each cell, by means of its nerve fibres and the pro- cesses that spring- from it, may be considered as a central station of an electric system. It can receive messages from parts more or less distant. It can dispatch messages in response to those received. Finally, it can store up such information as may be carried to it from time to time for future use, artording us, at the same time, memories of past events. It will simplify description if we consider each of the anatomical elements of the brain separately. THE BEAIN CELLS. These are placed chiefly upon the exterior of the organ, which is thrown into alternating ridges and depressions, somewhat like a fan when half closed. The ridges are called the convolutions, and the depres- sions are termed sulci; or fissures, in case they are deeper than the rest. The gray matter upon the exterior of the brain is called the cortex.'''' The cerebral cortex is ahme associated with consciousness and voli- tion. Like gray matter found in otlier regions of the organ, the cortex consists of brain cells and a cement (formed of connective-tissue elements) that binds them together. This is called the neuroglia.''^ Masses of brain cells are found imbedded within the substance of the organ; but their functions are less well determined than those of the cortical gray matter. The corpus striatum* and the optic thalamus are certainly the largest and perhaps the most important of these ganglionic masses. If we study the appearance of the brain cells under the micro- scope, we find that different convolutions of the brain are peopled with cells that have individual characteristics of form and construction; hence we are justified (from an anatomical stand-point alone) in attrib- uting different functions to individual areas of the cortex. This view is sustained, furthermore, b}' physiological and pathological investigation. We may consider each cell within the brain as possessing an individ- uality. Each is intrusted with and controls some particular function. Each is in telegraphic communication with other cells, and participates constantly in the growth and development of some special region of the body, acting in harmonj' with its fellows. Luys, who has carefully in- vestigated the structure of these minute bodies, says of them : Imagina- *I apply the term corpus striatum throughout this work to its two halves (the caudate and lenticular nuclei, Fig. 6) collectively. Many of the German authorities em- ploy it as synonymous with the caudate nucleus alone.