Dull Brains and Frozen Feet: A Historical Essay on Cold.

This essay will review historical and medical aspects of cold exposure, hypothermia, and frostbite during the Napoleonic era. The 19th century writings of Dominique Jean Larrey, Pierre Jean Moricheau-Beaupré, and others are used to provide an evocative supporting narrative to illustrate some of the cold illnesses, physiology, and theory of both an earlier era and the present time. Medical care for over a century followed the how but not the why of treating frostbite and hypothermia slowly with snow or cold water rather than heat. There were 2 main reasons: First was a practical attempt to limit gangrene. Less known, and long forgotten, is a major rationale based on the erroneous theory of heat called "the caloric." Because of these 2 reasons, the slow method of "cold warming" remained standard medical practice well into the 20th century. Although these recommendations are now known to be flawed, some of the reasons behind them will be discussed, along with early but correct observations on afterdrop and circumrescue collapse. There is a long backstory of treatment from 1812 to the present.

Origin, Evolution and Clinical Application of the Thermometer.

Although Galileo, Fahrenheit and Celsius are the names generally associated with the origin of the thermometer and its scale, many others were involved in bringing into existence the instrument we use today to monitor body temperature. In fact, the seed from which the thermometer arose was planted long before those credited with inventing it made their contributions, and nurtured by many other investigators during its evolution and clinical application.

Early evolution of the thermometer and application to clinical medicine.

By the time of Hippocrates and Galen the notion of fevers and temperature were known. Through ensuing centuries, ancient Greek, Roman, and medieval savants and physicians made additional contributions to the understanding of fever, temperature, and thermometry. By the end of that era, there was a working definition of what constitutes a rationale temperature scale, the distinction between fever as a symptom and fever as a disease, an elaborate classification scheme for temperature, hypotheses as to the causes of fever, and methods for measuring fevers. Based on the definition of fever at that time, the 16th century scientist Galileo promulgated production of thermometric instruments hundreds of years before they were routinely used in the clinical setting. In this work we examine the history of fever and clinical thermometry in the ancient world through the end of the eighteenth century with descriptions of instruments for its measure and human relationship to fever.

Measuring Fire: Herman Boerhaave and the Introduction of Thermometry into Chemistry.

This essay examines Herman Boerhaave's work with the instrument maker, Daniel Gabriel Fahrenheit, on integrating the thermometer into the practice of eighteenth-century chemistry. Boerhaave utilized the thermometer to generate empirical evidence for the existence and actions of his instrument, "fire," by incorporating the instrument into pedagogical demonstrations, chemical research on heat, and, finally, the performing of operations. I examine how the use of the thermometer altered the chemists' traditional approach to heat, based on skilled sense perception and experiential judgment, and suggest that the threat to traditional practice posed by the instrument explains some of the resistance to it among some chemists in the mid-eighteenth century.

Sir George Shuckburgh Evelyn (1751-1804): precision in thermometry.

The universal clinical procedure of recording a patient's temperature depends upon the accuracy of thermometers. This in turn depends upon the accuracy of two fixed datum points (the freezing and boiling points of water) and subsequently on the fine calibration of the etched scale between them. Anders Celsius (1701-44) defined the boiling point of water as the upper fixed point of the thermometric scale, originally designated as 0°C but inverted by Carl Linnaeus (1707-78) to read 100°C. In 1724 Gabriel Fahrenheit (1686-1736) had observed that the upper fixed point, that of boiling water, varied with changes in atmospheric pressure. An English scientist, Sir George Shuckburgh (after 1794 known as Sir George Shuckburgh Evelyn), addressed this problem and over the period 1774-79 he defined the relationship of the temperature of boiling water to barometric pressure. This latter variable changed both with the ambient meteorological conditions of the moment and the height above sea level at which the calibrations were made. Clinical thermometry depends on an accuracy of 0.1°C in both the baseline and the tracking of a patient's temperature but Shuckburgh's experiments showed that the upper fixed point of reference, that of boiling water, could change by up to 10°C. He demonstrated that these variables must be measured and controlled in the manufacture and calibration of thermometers. Sir George Shuckburgh Evelyn published his results in the Philosophical Transactions of The Royal Society (1777-79) and made possible the accuracy of thermometry on which patient care depends.

Molecular thermometry.

Conventional temperature measurements rely on material responses to heat, which can be detected visually. When Galileo developed an air expansion based device to detect temperature changes, Santorio, a contemporary physician, added a scale to create the first thermometer. With this instrument, patients' temperatures could be measured, recorded, and related to changing health conditions. Today, advances in materials science and bioengineering provide new ways to report temperature at the molecular level in real time. In this review, the scientific foundations and history of thermometry underpin a discussion of the discoveries emerging from the field of molecular thermometry. Intracellular nanogels and heat sensing biomolecules have been shown to accurately report temperature changes at the nanoscale. Various systems will soon provide the ability to accurately measure temperature changes at the tissue, cellular, and even subcellular level, allowing for detection and monitoring of very small changes in local temperature. In the clinic, this will lead to enhanced detection of tumors and localized infection, and accurate and precise monitoring of hyperthermia-based therapies. Some nanomaterial systems have even demonstrated a theranostic capacity for heat-sensitive, local delivery of chemotherapeutics. Just as early thermometry rapidly moved into the clinic, so too will these molecular thermometers.

The myth of the boiling point.

Around 1800, many reputable scientists reported significant variations in the temperature of pure water boiling under normal atmospheric pressure. The reported variations included a difference of over 1 degree C between boiling in metallic and glass vessels (Gay-Lussac), and "superheating" up to 112 degrees C on extracting dissolved air out of water (De Luc). I have confirmed most of these observations in my own experiments, many of which are described in this paper. Water boils at the "boiling point" only under very particular circumstances. Our common-sense intuition about the fixedness of the boiling point is only sustained by our limited experience.

When water does not boil at the boiling point.

Every schoolchild learns that, under standard pressure, pure water always boils at 100 degrees C. Except that it does not. By the late 18th century, pioneering scientists had already discovered great variations in the boiling temperature of water under fixed pressure. So, why have most of us been taught that the boiling point of water is constant? And, if it is not constant, how can it be used as a 'fixed point' for the calibration of thermometers? History of science has the answers.

[Fever--a millenarian subject]. / Fieber--Thema seit Jahrtausenden.

Since the antiquity up to the 19th century fever goes for an illness of its own rights. About 1900 temperature measurement has become clinical routine and fever synonymous with elevated body heat. In the time before accelerated pulse rate was the pathognomic sign. The detection of specific pathogen organisms leads to a new understanding of nosology and to the dissolution of the fever entity. However the antipyretic therapy remains essentially the same until the appearance of antibiotics.

The historical development of thermometry and thermal imaging in medicine.

Human body temperature has been an important part of medicine since very early times. However, until the thermometer was developed in the 16th century measurement was not possible. Some 200 years later, Wunderlich laid the foundation for clinical thermometry, and temperature charts became commonplace throughout the world. More recently thermal imaging has broadened the understanding of body surface temperature in health and disease. Standards for computer-assisted infrared imaging are well developed, and present-day fast high-resolution imaging is less expensive and more reliable than it was 40 years ago.

Ocular surface temperature: a review.

PURPOSE: To review the evolution in ocular temperature measurement during the last century and examine the advantages and applications of the latest noncontact techniques. The characteristics and source of ocular surface temperature are also discussed. METHODS: The literature was reviewed with regard to progress in human thermometry techniques, the parallel development in ocular temperature measurement, the current use of infrared imaging, and the applications of ocular thermography. RESULTS: It is widely acknowledged that the ability to measure ocular temperature accurately will increase the understanding of ocular physiology. There is a characteristic thermal profile across the anterior eye, in which the central area appears coolest. Ocular surface temperature is affected by many factors, including inflammation. In thermometry of the human eye, contact techniques have largely been superseded by infrared imaging, providing a noninvasive and potentially more accurate method of temperature measurement. Ocular thermography requires high resolution and frame rate: features found in the latest generation of cameras. Applications have included dry eye, contact lens wear, corneal sensitivity, and refractive surgery. CONCLUSIONS: Interest in the temperature of the eye spans almost 130 years. It has been an area of research largely driven by prevailing technology. Current instrumentation offers the potential to measure ocular surface temperature with more accuracy, resolution, and speed than previously possible. The use of dynamic ocular thermography offers great opportunities for monitoring the temperature of the anterior eye.