We know that many diseases can cause a rise in body temperature, but doctors in the 19th century had to diagnose a fever with a cursory judgment, and without accurate measuring instruments, some of them were late or inaccurate, leading to treatment that made patients worse or even killed them. In fact, as early as the 16th century, the Italian biologist Galileo made the first thermometer to measure the body temperature.
Galileo invented the thermometer 1
Galileo was then teaching at a university in Venice. Some doctors came to him and begged him: Sir, when a person is ill, his temperature will generally rise. Can you find a way to accurately measure his temperature to help diagnose his illness?
Let me stop you here: not all diseases cause a rise in body temperature. The most common diseases that cause a rise in body temperature are infectious diseases, especially bacterial infections. Many diseases do not themselves cause a rise in body temperature. The most common are chronic diseases such as bronchial asthma, coronary heart disease, and peptic ulcers. So the doctor’s words are not rigorous.
The doctor’s sincere request made Galileo feel hard to refuse. In order to produce this medical instrument, Galileo kept thinking, but always could not come up with a good way.
One day, Galileo was giving an experiment to his students. The students were entranced by his operation and explanation. He asked the students: When the temperature of the water rises, especially when it boils, why does it rise in the tank?
Student: Because when water reaches its boiling point, its volume increases and it expands and rises. As the water cools, it shrinks, and then falls back down. The student gave the correct answer.
The common sense answer by the student said, immediately make Galileo came to the idea of making a thermometer, Galileo excitedly thought, the temperature of water changes, the volume also changes, so in turn, from the volume of water change, can not also measure the change in temperature?
Galileo was happy to forget himself, even in class, immediately returned to the office, according to the principle of thermal expansion and contraction, to do experiments.
Galileo’s invention of the thermometer 2
On the basis of this principle, in 1592 Galileo finally succeeded in producing the first thermometer, a long and thin graduated glass tube with the closed end shaped like a ball and the open end stuck in water. When the ambient temperature changes, the water column in the tube changes with it, so the temperature is known. However, since water is exposed to the atmosphere, and the height of the water column is affected by atmospheric pressure as well as temperature, it is often not accurate to measure the change of temperature only by the height of the water column.
Before that, doctors used the palm of their hands to feel the patient’s temperature. So the world’s first thermometer quantified a person’s body temperature with a numerical value. Although the thermometer did not yet measure body temperature accurately, it was a landmark in the history of body temperature studies by making the body temperature felt in the palm of your hand visible.
Diagnosis of disease and temperature
The earliest thermometers did have scales, but they were drawn according to the doctor’s personal preference. Even so, when it comes to measuring people’s temperatures with the thermometer, doctors have come to realize that healthy people always keep their temperatures at a certain level. It was a century before the medical world could properly measure the temperature of a healthy person. The boiling point was discovered in 1691, and it was linked to the previously discovered freezing point of water to establish a standard for measuring temperature. In 1714, German physicist Walter Fahrenheit used a leather bag filled with mercury to measure the temperature, which was called the Fahrenheit thermometer. Using this temperature to measure body temperature, a healthy person’s body temperature is 96 degrees Fahrenheit. By the way, in China, the temperature scale invented by Fahrenheit is called “Fahrenheit,” denoted by the symbol “℉.” But it was not until 1858 that thermometers were used to treat medical diseases. This year, a very famous German doctor Wendlich published “Disease and Body temperature”, in which he pointed out that according to different diseases, the body temperature is also different. After that, a temperature check became an integral part of the diagnosis. The thermometer used at that time was 30 centimeters long and took five minutes to measure. And when pulled out, the column of liquid inside the thermometer, instead of staying in place as in mercury thermometers today, fell rapidly.
The repeated improvement of the thermometer
Galileo’s first thermometer accuracy is not enough, in order to solve this problem, in 1654, Galileo’s students to use alcohol instead of water, made a thermometer not affected by atmospheric pressure, and for the first time by the Italian professor of medicine Santorio used to measure human body temperature. About 10 years later, the Italians made mercury thermometers instead of alcohol, and the mercury thermometers began to be widely used in clinical diagnosis. Although mercury thermometers are widely used, many inconveniences have been found.
In 1714, Gabriel Fahrenheit developed a mercury thermometer with a scale set at the freezing point of water and the temperature of a human being. A Dutch doctor used it to take the temperature of a feverish patient, but the thermometer was still too large for most doctors to use quickly.
After the 1850s, medical science such as bacteriology and cytology developed rapidly, and the causes of many diseases were identified. In addition, patient-specific temperature curves have also been found, establishing the status of clinical temperature detection. In the background of this era, in 1867, a doctor named Albart in London, England, according to the characteristics and needs of measuring human body temperature, developed a special thermometer for measuring human or animal body temperature, so far, thermometer was confirmed to be born, and has been in use until now.
Of course, with the development of modern technology, thermometers are constantly being updated. In 1984, a Finnish medical device designer invented an even more convenient and accurate electronic thermometer. Shortly thereafter, a medical device company in the United States invented and developed a special pacifier type thermometer for infants. It can be predicted that in the rapid development of high-tech tomorrow, will develop a more advanced, more scientific, more accurate new type of thermometer.