A treatise on nervous and mental diseases : for students and practitioners of medicine.
- Gray, Landon Carter, 1850-1900
- Date:
- 1893
Licence: Public Domain Mark
Credit: A treatise on nervous and mental diseases : for students and practitioners of medicine. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![PART I. INTRODUCTORY. CHAPTER I. ANATOMICAL INTRODUCTION. Just as it has not been my purpose to write a text-book upon electricity, so it lias not been my intention to compose a manual of the anatomy of the nervous system; I propose only to state such salient facts about the anatomy and the physiology of the latter as are necessary to an intelligent understanding of nervous and mental disease. In doing this, abstruse matters that the future may show to be of great value will not be dwelt upon, but I shall rather confine my attention to the living issues of the clay. The nerve cell is the essential element in nervous tissue. In it go on all the peculiar molecular processes which endow the nervous system with individuality. It is the very inner citadel of nervous life. To it all the other textural structures are subsidiary. It is nourished by the arterioles and lymphatics, drained by the venules, upheld by the connective tissue. These cells of the nervous tissue are peculiar in their appearance, differing from the cells of other tissues as the cells of other tissues differ among themselves. Of the cells of the different regions of the nervous system, also, each has a histological visage of its own, but they have certain characteristics in common. They have each, for instance, a distinct kernel or inner spot, and inside of this kernel still another and smaller kernel—what are known in histological technology as the nucleus and nucleolus. However much the cells may vary in shape, each sends oflP from itself two or more elongations. These are called processes, from the Latin word pwcedere, to go forward. We are warranted in believing that these processes are as distinct in their destination and function as they are in their appearance. Deiters and Wagner claim, their observations having been confirmed by many others, that the straight unbranching process is the axis cylinder of a nerve, and it is known as the axis- cylinder process. It becomes covered with the medullary and con- nective-tissue sheaths of a jx'ripheral nerve, of which we shall soon S})eak. It is stiff and hyaline looking under the microscope, so that it is in marked contrast ^vith the ])roto]>lasm of the liody of the; cell; and as this granular, fine, piginented protoplasm is continued in the 2](https://iiif.wellcomecollection.org/image/b21220670_0019.jp2/full/800%2C/0/default.jpg)
