Page:Encyclopædia Britannica, Ninth Edition, v. 13.djvu/109

INSANITY life common to their inhabitants for arriving at conclusions as to its cause, nothing has been definitely determined. Cretinism has occupied the attention of many eminent observers, but the various theories they have advanced have been in succession overturned. It has been suggested that the condition is due to the constant use of snow water, or to the presence of sulphate of iron or of lime in water, but none of these theories admit of universal application. That the disease is due to some geological or climatic cause appears certain from the fact, stated by Baillarger, that it disappears from a family in one or two generations after removal to a healthy climate, and may even be prevented by the gravid mother leaving a valley where it is rifo for localities where cretinism is unknown. The physical and mental symptoms of cretinism are so closely allied in essentials to those of congenital idiocy as not to demand a separate description. The marked features of the disease are its endemic nature and its intimate connexion with goitre. See CRETINISM. Eibliogrnpliy. Rapport de la Commission dc S. M. le Roi de Sar- daigne, jwur etudier le Cretinismc, Turin, 1848 ; B. Niepce, Traite die Goitre et du Cretinismc, Paris, 1851 ; Beobaclitungcn iibcr den Cretinismus, published by the physicians of the hospital at Maria- berg, Tubingen, 1850, 1851, and 1852 ; Guggenbiihl, Die Cretincn- Hcilanstalt auf dem Abcndbcrg, Bern and St Gall, 1853 ; Virchow, Untcrsuchungcn iiber die Entwickclung des Schadelgrundcs im (jesunden und krankhaftcn Zustandc und iiber den Einfliiss derselbcn aitfScMddform, Gcsiclitsbildung, und Geliirnbau (Berlin, 1857), and Gesammte Abhandhmficn zurivisscnscliaftliclienMcdicin (Frankfort, 1856) ; Saint Lager, Etudes sur les Causes du Cretinisme et du Goitre cndemique, Paris, 1867, and Dcuxieme Serie d Etudes sur les Causes dio Cretinisme, Lyon, 1868 ; Baillarger, Enquete sur le Goitre ct le Cretinisme, Paris, 1873 ; Max Parchappe, Etudes sur le Goitre ct le Cretinismc, edited and annotated by L. Lunier, Paris, 1874 ; Lombrosa, Rivista Clinica di Bologna, pt. 7, July 1873, andpt. 11, November 1873 ; Ireland, Edinburgh Medical Journal for August and September 1875, and On Idiocy and Imbecility, 1877. The last-named is the standard work on idiocy. ACQUIRED INSANITY. Pathology. It is predicated in treating of Acquired Insanity that we have to deal with brains congenitally perfect, the exercise of whose functions has been normal until the incidence of disease. A full description of the tissues of the healthy brain will be found in the article ANATOMY (vol. i. pp. 869- 880), a careful perusal of which will very materially assist the reader in following the present remarks on pathology. A short resapitulation of certain anatomical facts is, how ever, necessary. The purely nervous structures of the brain consist of very delicate fibres and cells, the latter occurring only in the grey matter. It is richly supplied with blood vessels, the supply being six times greater to the grey matter than to the white. These tissues are supported and separated one from the other by a connective tissue, or interstitial matter, the neuroglia ; the whole organ is enveloped in membranes which separate it from the skull. By one system of independent fibres (the expansion system) communication is maintained between the spinal cord, the central ganglia, and the cortical grey matter ; by a second system of fibres (the commissural), corresponding and identical regions of the grey matter of the two opposite hemispheres are united ; and by a third system (the hori zontal) communication is maintained between parts of the same hemisphere. The cells communicate one with the other by means of processes or poles, fine projections from the body of the cell. The observations of Cleland and Boll show that the apical processes become connected with the fibres as they go to the periphery ; the basal processes loop with the horizontal fibres, and also, by means of their recurrent poles, with those of the expansion series. But it is of great importance to observe that we have no evidence of fibre communicating directly with fibre, or no certain proof that one series of fibres communicates directly with others ; in fact, all anatomical demonstration goes to prove the individuality and isolation of fibre, the processes of the cells being the connecting link. It is universally accepted that the cerebral cells possess the vital property of generating, receiving, and transmitting nervous influences, and that the fibres are the organs by means of which these influences are received and communicated. In the words of Herman, " in a part of the central organs (the cortical cells) certain material processes are accompanied in an inexplicable manner with wholly undefinable phenomena which characterize what we term conscioiisness" The term mind may be applied to the combination of all the actual and possible states of consciousness of the organism. "We have a right to presuppose that in the brain, as in other organs of the body, the normal exercise of function is dependent on a perfect maintenance of the anatomical relations of the component structures, and conversely that morbid conditions of these structures must affect the whole economy more or less seriously" (Bucknill and Tuke). In studying brain pathology it must be kept in view that the brain cannot, like the lungs, liver, and kidneys, cast any of its functions on other organs ; it must do its own work, rid itself of its effete matter, and of the products of injury or disease, and provide within itself for the resump tion of functions, the exercise of which has become im paired from whatever cause. Solutions of continuity, preventing perfect maintenance of the component cerebral tissues, may arise from (1) idiopathic causes, i.e., causes originating primarily in tho brain; (2) traumatic causes (injury to the head); (3) the effects of other neuroses (morbid nerve conditions); (4) ad ventitious products (tumours, &c.) ; (5) morbid conditions of the general system secondarily implicating the brain ; (6) evolutional conditions of the system concurrently affecting the brain ; (7) toxic agents (poisons). In the case of insanity the results of morbid action are confined to the convolutions of the superior surface of the brain, and to the upper part of its lateral aspects ; for the most part its base and inferior lateral aspects and the cerebellum are un affected. It is true that in old standing cases the central ganglia present lesions, but these are for the most part secondary, and are due to the action of disease in the superior convolutions. 1. Idiopathic changes occur from disease affecting the tissues, the cause of which it may be impossible to trace, as, for instance, acute inflammation, which, however, is not a frequent cause of insanity. Diffused subacuto inflammation is held to be a much more fruitful cause, producing increase (sclerosis) of the neuroglia, degeneration of the cells, destruction (atrophy) and dis placement of fibres, and aneurism, distortion, and oblitera tion of vessels. A large and important class of causes of idiopathic morbid action is due to over-excitation of the brain. The causes of over-excitation of the brain functions are those which, in most works on insanity, arc spoken of as " moral " (grief, anxiety, domestic complications, dis appointment, terror, sorrow or joy, religious or political excitement, the exercise of the mental faculties by study unduly prolonged or conducted under adverse circumstances) in contradistinction to " physical" causes, a distinction which implies some material difference in their method of operation. To the most superficial observer, the deformed head of the idiot, and the paralysis of mind and body which follows on the rupture of a cerebral vessel, are coarsely material conditions; but when mental aberration follows on mental excitement, men are prone to regard it more ^as a derangement of function than as an evidence of deteriora-