Sources of Thought Two 19th-century Chronobiologists: Thomas Laycock and Edward Smith

This article describes the works of two 19th-century chronobiologists. Thomas Laycock (1812-1876), who held the Chair of Medicine in Edinburgh from 1855-1876, published a series of seven articles in Lancet, all dedicated to periodicities in “vital phenomena.” Laycock considered the understanding of periodicities essential for the advancement of the treatment of diseases. Edward Smith (1818-1874) was a pioneer in experimental chronobiology. In his 1861 book entitled: Health and disease as influenced by daily, seasonal and other cyclical changes in the human, Smith summarized a large number of experiments in which he investigated the occurrence of periodicities in pulse rate, urine flow, urea excretion, and respiration. From his experimental results and those of others, Smith drew practical conclusions regarding patients' care, the timing of drug administration, and the design of night work.     

Sources of Thought Two 19th-century Chronobiologists: Thomas Laycock and Edward Smith

This article describes the works of two 19th-century chronobiologists. Thomas Laycock (1812-1876), who held the Chair of Medicine in Edinburgh from 1855-1876, published a series of seven articles in Lancet, all dedicated to periodicities in “vital phenomena.” Laycock considered the understanding of periodicities essential for the advancement of the treatment of diseases. Edward Smith (1818-1874) was a pioneer in experimental chronobiology. In his 1861 book entitled: Health and disease as influenced by daily, seasonal and other cyclical changes in the human, Smith summarized a large number of experiments in which he investigated the occurrence of periodicities in pulse rate, urine flow, urea excretion, and respiration. From his experimental results and those of others, Smith drew practical conclusions regarding patients' care, the timing of drug administration, and the design of night work.     

Two 19th-century chronobiologists: Thomas Laycock and Edward Smith.

This article describes the works of two 19th-century chronobiologists. Thomas Laycock (1812-1876), who held the Chair of Medicine in Edinburgh from 1855-1876, published a series of seven articles in Lancet, all dedicated to periodicities in "vital phenomena." Laycock considered the understanding of periodicities essential for the advancement of the treatment of diseases. Edward Smith (1818-1874) was a pioneer in experimental chronobiology. In his 1861 book entitled: Health and disease as influenced by daily, seasonal and other cyclical changes in the human, Smith summarized a large number of experiments in which he investigated the occurrence of periodicities in pulse rate, urine flow, urea excretion, and respiration. From his experimental results and those of others, Smith drew practical conclusions regarding patients' care, the timing of drug administration, and the design of night work.     

A biohistory of 19th-century African Americans: The burial remains of a Philadelphia cemetery.

By Lesley M. Rankin-Hill. Westport, CT: Bergin and Garvey. 1997. 203 pp. ISBN 0-89789-435-9. $59.95 (cloth). © 1998 Wiley-Liss, Inc.     

Childhood conditions, migration, and mortality: migrants and natives in 19th-century cities

Migrants often have lower mortality than natives in spite of relatively unfavorable social and economic characteristics. Although migrants have a short-run advantage due to the selective migration of healthy workers, persistent health and mortality differences between migrants and natives may be long-run effects of different experiences in childhood. We made use of a natural experiment resulting from rural-to-urban migration in the mid-19th century. Mortality was much higher in urban areas, especially in rapidly growing industrial cities. Migrants usually came from healthier rural origins as young adults. Data used in this study is available from 19th-century Belgian population registers describing two sites: a rapidly growing industrial city and a small town that became an industrial suburb. We found evidence of three processes that lead to differences between the mortality of migrants and natives. First, recent migrants had lower mortality than natives, because they were self-selected for good health when they arrived. This advantage decreased with time spent in the destination. Second, migrants from rural backgrounds had a disadvantage in epidemic years, because they had less experience with these diseases. Third, migrants from rural areas had lower mortality at older (but not younger) ages, even if they had migrated more than 10 years earlier. We interpret this as a long-run consequence of less exposure to disease in childhood.     

19th-century academic examinations for physicians in the United States Army Medical Department.

During the latter half of the 19th century, the United States Army commissioned medical officers or hired civilian physicians to serve its troops. The civilian physician signed a contract for services, and the candidate for a commission was subjected to rigorous examinations before becoming an officer. The rigorous testing of prospective medical officers was necessary because of the lack of standardization in the education of physicians. Examples of the test, statistics, and individual records show how the Army dealt with unqualified candidates.     

Enamel hypoplasia and age at weaning in 19th-century Florence,Italy

A sample representing a population of the Florence district of middle 19th century was studied to determine the age of occurrence of enamel hypoplasias. The age interval most affected was that between 1.5 and 3.5 years. Historical sources on weaning habits of 19th-century Italian populations indicate a weaning period between 12 and 18 months. This is in agreement with the data on enamel defects, showing that children of post-weaning age are more subject to stress. Wide “grooves”, with prolonged duration, are concentrated between 2 and 2.5 years, whereas “lines” occur primarily between 2.5 and 3 years. We suggest that this distribution could reflect the gradual introduction of dietary supplements until weaning is complete. © 1994 Wiley-Liss, Inc.