NEUROPATHOLOGY.) Cellular Pathology.—The doctrine of the essential cellular nature of living things had been established by 1840. (See BIOL OGY : History.) Soon the conception of protoplasm as the physical basis of life, and the general structure of the cell, including the nucleus as an essential structure, came into clear view. The study of tissues—histology—was raised to the status of an independent science by the Swiss, Albrecht von Kolliker (1817-1905) (q.v.), a pupil of Johannes Muller (q.v.). Kolliker wrote the first text book of histology in 1850.
A very important influence on medical thought was that of Rudolf Virchow (1821-1902) (q.v.). His great achievement was the extension of the cell theory into the analysis of diseased tissues. In his work Cellular Pathology, first published in 1858, he analysed diseased tissues from the point of view of cell forma tion and cell structure. Important sections of the science of cellu lar pathology were explored so well by Virchow that they have been little extended by his successors. He initiated the familiar idea that the body may be regarded as a "cell state in which every cell is a citizen." Disease is often but civil war. The white blood corpuscles, which have the power of engulfing and rendering innocuous bacteria and other foreign bodies, have been compared to police or scavengers. Some of these ideas had been adumbrated by A. V. Waller (1816-70) and were further developed by the Russian biologist working in Paris, Elie Metschnikoff (1845-1916) and by the English worker, Sir Almroth Wright (b. 1860.
Since Kolliker and Virchow, the study of the intimate structure and workings of the cells themselves, as distinct from the tissues, has become a separate science, cytology (q.v.), which has been further extended to the study of cells in disease cyto-pathology. Among the major developments of cyto-pathology is the study of abnormal new growths, among which cancer (q.v.) takes a leading
place. Apart from these special developments, there has been an extensive and intensive exploration of the microscopic appear ances of diseased organs. This exploration has been illuminated by our knowledge of the nature and action of the micro-organisms of disease, and has been guided by experimental methods of pro ducing disease in animals, a procedure which has become of in creasingly greater importance since the days of Pasteur and Koch.
From this period, synchronous with the rise of bacteriology, we must leave the history of medicine which, from now onwards, passes within the range of special articles on various medical subjects to which the reader is referred.
BIBLioGRAPHy.—General: Mitteilungen z. Geschichte d. Medizin u. d. Naturwissenschaften from 1902 ; Isis from 1913 ; F. H. Garrison, Intro duction to the History of Medicine (1928) ; C. Singer, Short History of Medicine (1928).
Ancient Medicine: C. Singer, Greek Medicine and Greek Biology (1921) ; • G. Sarton, Introduction to the History of Science (1927) ; W. H. S. Jones and E. T. Withington, Hippocrates with an English Translation (1922-28).
Mediaeval Medicine: M. Neuburger, History of Medicine (1916 21) ; C. Singer, From Magic to Science (1928) ; Fasciculo di Medicine (1925).
Special Departments of Medicine: C. Singer, Evolution of Anatomy and Discovery of the Circulation of the Blood (1922) ; M. Foster, His tory of Physiology (190I) ; M. Neuburger, Die historische Entwicklung d. exp. Gehirn u. Riickenmarksphysiologie (1897) ; E. Gurlt, Geschichte d. Chirurgie (1898) ; P. Lecene, L'Evolution de la chirurgie (1923) ; H. Fasbender, Geschichte d. Geburtshilfe (1906) ; H. Schelenz, Geschichte d. Pharmazie (1904) J. Hirschberg, Geschichte d. Augenheilkunde (1908-18). (C. SO