The doctrine of evolution in its application to pathology / by William Aitken.

  • Aitken, William Henry, Sir, 1825-1892.
Date:
1886
Catalogue details

Licence: Public Domain Mark

Credit: The doctrine of evolution in its application to pathology / by William Aitken. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    them now. A disease as well as a race does not attract our attention in Nature until it has in all probability existed for a considerable length of time, and then it is too late to inquire into the conditions of its origin. * Evolution cannot take the place of history. It is only by studying such history^ as Hirsch's Geographical and Historical Pathology, and learning what it can teach us, that we can speculate from the known to the unknown. We may thus attempt to reason out the probable and necessary prehistoric antecedents of diseases from facts still within our reach. Alike in geological and biological sciences we must reason from what is going on round about us, in order to appreciate the changes in the past which have influenced the conditions of the present, and will continue to influence the conditions of the future in all the sciences, amongst which pathology can be no exception. The cumu- lative importance of separately infinitesimal elements is the very keynote and special peculiarity of the biological method of thinking which Charles Darwin has taught us to employ. He has shown us that the infinitely small, infinitely separated, may become in process of infinite years infinitely important; -f and systems of changes now in progress in the organic world will afford, when fully understood, a complete key to the interpretation of the living creation in past ages. \ And still more to help us to interpret the past from the present, results such as those elicited by the statistics of the late Dr. Farr are as valuable as an experimental philosopher could have deduced from his experiments if he had had the power to expose the population to great vicissitudes of heat and cold, of dampness and dryness; to the changes incidental to differences in the prices of food ; to air and water of different degrees of impurity; and to destructive epidemics. Thus we learn that in the same circumstances the same number of people die, at the same ages, of the same diseases, year after year; organised bodies being governed by laws as fixed as those which govern the stars in their courses. Certain changes of condition, within certain limits, produce no appreciable effects ; but beyond those limits, the effects are in some regulated proportion to the intensity of the causes • varying, however, also ivith the state of the bodies subviitted to their action, as is evident by studying the effects on the two sexes at different ages. § Mr. Darwin also makes special refer- * Huxley, Lay Sermons, Addresses, and Reviews, p. 324. t Memoir of Charles Darwin, by Grant Allen, I. c. 1 Lyell, AntiquitTj of Man, 3rd ed., 18G3, ]}. 393. ' § Vital Statistics, by Dr. William Fai-r, I. c, p. 142.