of not dissimilar character, whereby a vessel is blocked not by a travelling particle, but by a clotting of the blood in situ, probably on the occasion of some harm to the epithelial lining of the vessel. Such injuries are apt to occur in syphilitic endarteritis, or senile arterial decay, whereby an artery may be blocked permanently, as if with an embolus, and the area supplied by it, in so far as it was dependent upon this vessel, deprived of nutrition. These events, although far more mischievous in the brain, the functions of which are far-reaching, and the collateral circulation of which is ill-provided, are seen very commonly in other parts.
It is in the structure of the brain itself that modern research has attained the most remarkable success. In 1861 an alleged “centre” of speech was detected, by a combination of clinical and pathological researches, by Paul Broca (1824–1880). By these means also, in the hands of Hughlings-Jackson, and more conclusively by experimental research initiated by G. T. Fritsch (b. 1838) and T. E. Hitzig (b. 1838), but pursued independently and far more systematically and thoroughly by David Ferrier (b. 1843) and his disciples, it was proved that the cerebrum is occupied by many such centres or exchanges, which preside over the formulation of sensations into purposive groups of motions—kinaesthesis of H. Charlton Bastian (b. 1837). The results of these experimental researches by many inquirers into the constitution of the brain have transformed our conceptions of cerebral physiology, and thrown a flood of light on the diseases of the brain. Not only so, but this mapping of the brain in areas of function now often enables the clinical physician to determine the position of disease; in a certain few cases of tumour or abscess, so precisely that he may be enabled to open the skull above the part affected and to extirpate it—operations which are surely a triumph of science and technical skill (Lister, W. MacEwen, V. Horsley).
The remarkable discovery of the dual nature of the nervous system, of its duplex development as a lower and upper system of “neurons,” has shed much light upon the problems of practical medicine, but this construction is described under Brain; Neuropathology; Muscle and Nerve, &c.
In mental diseases little of first-rate importance has been done. The chief work has been the detection of chronic changes in the cortex of the brain, by staining and other histological methods, in degenerative affections of this organ—Theodor Meynert (1833–1892), W. Griesinger (1817–1868), Bevan Lewis—and in the separation from insanity due to primary disease or defect of nerve elements of such diseases as general paralysis of the insane, which probably arise, as we have said, by the action of poisons on contiguous structures—such as blood-vessels and connective elements—and invade the nervous matter secondarily. Some infections, however, seem to attack the mental fabric directly; intrinsic toxic processes which may be suspected on the detection of neurin and cholin in the fluids of the brain (F. W. Mott). Truer conceptions of normal psychology have transformed for us those of the morbid—P. Pinel (1745–1826), Griesinger, Henry Maudsley (b. 1835), Mercier, Kräpelin, Rivers—and indicated more truly the relations of sanity to insanity. In the treatment of insanity little has been done but to complete the non-restraint system which in principle belongs to the earlier part of the 19th century (Pinel, Tuke, R. G. Hill, J. Conolly). An enormous accumulation of lunatics of all sorts and degrees seems to have paralysed public authorities, who, at vast expense in buildings, mass them more or less indiscriminately in barracks, and expect that their sundry and difficult disorders can be properly studied and treated by a medical superintendent charged with the whole domestic establishment, with a few young assistants under him. The life of these insane patients is as bright, and the treatment as humane, as a barrack life can be; but of science, whether in pathology or medicine, there can be little. A considerable step in advance is the establishment by the London County Council of a central laboratory for its asylums, with an eminent pathologist at its head: from this laboratory valuable reports are in course of issue. Provision for the reception and treatment of insanity in its earliest and more curable stages can scarcely be said to exist. Sufferers from mental disease are still regarded too much as troublesome persons to be hidden away in humane keeping, rather than as cases of manifold and obscure disease, to be studied and treated by the undivided attention of physicians of the highest skill. The care and education of idiots, initiated by Guggenbuhl and others, is making way in England, and if as yet insufficient, is good of its kind.
By the genius of René Théophile Laennec (1781–1826), diseases of the lungs and heart were laid on a foundation so broad that his successors have been occupied in detail and refinement rather than in reconstruction. In heart disease the chief work of the latter half of the 19th century was, in the first quarter, such clinical work as that of William Stokes and Peter Mere Latham (1789–1875); and in the second quarter the fuller comprehension of the vascular system, central and peripheral, with its cycles and variations of blood pressure, venous and arterial. Moreover, the intricacies of structure and function within the heart itself have been more fully discriminated (W. H. Gaskell, Aschoff, A. Keith, Wenkebach, J. Mackenzie). By the greater thoroughness of our knowledge of the physics of the circulation—Étienne Marey (b. 1830), Karl Ludwig (1816–1895), Leonard Hill—we have attained to a better conception of such events as arterial disease, apoplexy, “shock,” and so forth; and pharmacologists have defined more precisely the virtues of curative drugs. To the discovery of the parts played in disease by thrombosis and embolism we have referred above. With this broader and more accurate knowledge of the conditions of the health of the circulation a corresponding efficiency has been gained in the manipulation of certain remedies and new methods of treatment of heart diseases, especially by baths and exercises.
As regards pulmonary disease, pneumonia has passed more and more definitely into the category of the infections: the modes of invasion of the lungs and pleura by tuberculosis has been more and more accurately followed; and the treatment of these diseases, in the spheres both of prevention and of cure, has undergone a radical change. Instead of the close protection from the outer air, the respirators, and the fancy diets of our fathers, the modern poitrinaire camps out in the open air in all weathers, is fed with solid food, and in his exercise and otherwise is ruled with minute particularity according to the indications of the clinical thermometer and other symptoms. The almost reckless reliance on climate, which, at Davos for instance, marked the transition from the older to the modern methods, has of late been sobered, and supplemented by more systematic attention to all that concerns the mode of life of the invalid. The result is that, both in physicians and in the public, a more hopeful attitude in respect of the cure of phthisis has led to a more earnest grappling with the infection in its earliest stages and in every phase, with a correspondingly large improvement in prevention and treatment. Indeed, in such early stages, and in patients who are enabled to command the means of an expensive method of cure, phthisis is no longer regarded as desperate; while steps are being taken to provide for those who of their own means are unable to obtain these advantages, by the erection of special sanatoriums on a more or less charitable basis. Perhaps no advance in medicine has done so much as the study of tuberculosis to educate the public in the methods and value of research in medical subjects, for the results, and even the methods, of such labours have been brought home not only to patients and their friends, but also to the farmer, the dairyman, the butcher, the public carrier, and, indeed, to every home in the land.
It was in the management of pleurisies that the aid of surgical means first became eminent in inward disease. In the treatment of effusions into the pleura and, though with less advantage, of pericardial effusions, direct mechanical interference was practised by one physician and another, till these means of attaining rapid and complete cure took their places as indispensable, and were extended from thoracic diseases to those of the abdominal and other inner parts formerly beyond the reach of direct therapeutics. Lord Lister’s discoveries brought these new methods to bear with a certainty and a celerity previously undreamed of; and many visceral maladies, such as visceral ulcers, disease of the pancreas,
