A short history of stethoscopes

Today stethoscopes are a typical fixture around doctors’ necks. They are commonly used to listen to the sounds of the heart and lungs as well as the flow of blood during blood pressure readings.

The practice of percussion and immediate auscultation were popular in physical examinations by the early 1800s. In immediate auscultation, physicians placed their ear directly on the patient to observe internal sounds. A French physician named Rene Laennec (1781-1826) was a firm believer in this method of diagnosis. He worked to refine the auscultation procedure and link the sounds with specific physiological changes in the chest.

Immediate auscultation could be an awkward procedure, particularly for female patients.  In 1816, Laennec found himself in one of these situations. He rolled a few sheets of thick paper into a tube shape and applied the tube to the woman’s chest instead of his ear. Later, he made a more durable instrument out of wood and called it the stethoscope. It was a monaural model that consisted of one tube and was used on one ear.

monaural stethoscope, c1890

The first practical bi-aural stethoscope was made in 1851. Flexible tubing is required to make a stethoscope that allowed physicians to use both ears. While many physicians readily adopted monaural stethoscopes, the bi-aural stethoscopes were met with some skepticism. Doctors worried about hearing imbalances caused by using both ears instead of one. For this reason, many doctors continued to use monaural stethoscopes into the early 1900s.

Camman's biaural stethoscope, c1890-1900

The stethoscopes used today are very similar to the ones used in the 1930s. New materials such as flexible rubber, stainless steel, and tygon make them lighter and easier to use. The bells (the end of the instrument applied to patient’s body) have also become flatter. The application of electronic amplifiers to the stethoscope provided the next major modification. These stethoscopes amplified the sound heard by the physician and were capable of filtering high pitched tones in order to make faint tones louder. Some electronic models could provide visual or audio recordings that could be used in training or consultation as well.

Maico Stethetron, c1948

The stethoscope is one of the medical instruments whose development has been dependent on the invention of new materials such as rubber and stainless steel. The sounds the stethoscope produces has been aided by the better understanding of the relationship between anatomy and the laws of physics. Not only did doctors need to understand how to efficiently transmit sound through tubes, they also need to understand how sound waves reacted in the various tissues of the body. These are some of the issues explored in our upcoming exhibit “Tools of the Trade: The history of medical instrumentation.”

1890 Rx

Last week, while leafing through a 1890s medical book from the museum’s library, I found a small slip of paper between the pages. It was a prescription recipe for the pharmacy of H. Waterman in Ravenna, OH.

As I looked over the neat handwriting, I realized that the drug names were written in Latin and the measurements were given using the symbols of the apothecaries’ system. It occurred to me that this prescription might be very useful to illustrate the pharmaceutical measurement system in the upcoming Tools of the Trade exhibit. The weights in this system are broken down like this:

One pound = 12 ounces
One ounce = 8 drams
One dram = 3 scruples
or
One dram = 60 grains

So I set out to translate the Latin and measurements. It was so exciting to slowly figure out the ingredients and their effects. Here is the transcription and translation:

“Potassii Acetatis [Potassium acetate]                      2 drams
Potassii Nitratis [Potassium nitrate]                       1 dram
Spiritus Juniperis [Spirit of Juniper]                   11 fluid ounces
Aqum mentha piperita [Peppermint water]        4 fluid ounces
mix
A teaspoonful twice a day together with an occasional aperient at night.”

According to digitized pharmaceutical books from this time period on ChestofBooks.com’s health and healing section-

Potassium acetate and potassium nitrate were commonly used in low doses as diuretics.

Spirit of Juniper is very similar to gin and can contain as much as 35% alcohol. Notice that it is the main ingredient.

Peppermint water is a treatment of acute indigestion.

The physician is instructing the patient to take this prescription twice a day in addition to an occasional aperient (laxative) at night. In the research I’ve done for the pharmaceutical section of the Tools exhibit, it seems that prescriptions like this were common in the 1700s and 1800s. Physicians often prescribed medicine that would purge the body in some fashion.  These medicines might have been combined with the practice of bloodletting, which was common in the United States until the mid-1800s.

Physicians and pharmacists continued to write prescriptions in Latin until the turn of the 20th century. I also found another prescription recipe in our collection from Kent, OH in 1914. The drug names are given in English and the amounts are shown using the apothecaries system symbols. “Lactopeptine” is a digestion aid. At the bottom, the physician has instructed the pharmacist to make four ounces and write a message on the bottle that one dram of the medicine is to be taken in water every three hours.

Interesting Smithsonian exhibits on medicine

Common Threads exhibit by Jean Shin at the Smithsonian Museum of American Art:

This exhibit is made out of a collection of similar everyday objects. For example, “Chemical Balance III” makes lighted stalactite- and stalagmite-like sculptures out of empty prescriptions containers. According to the artist, this part of the exhibit speaks to a dependency on prescription medications.” Other installations include “Chance City” which is a cityscape made out of thousands of losing lottery tickets. “Everyday Moments” mimics the landscaping of the National Mall with old donated trophies. Find out more about the exhibit here. Look at behind the scenes photographs of this exhibit being installed at Jean Shin: Common Threads on Flickr.

“Balm of America” collection at the Smithsonian National Museum of American History:

This is an interesting and valuable database of patent medicines that has a wide range of audience and use. The product names and ingredients are amusing to almost anyone. For example, Dr. Strong’s Life Force Pills, Kickapoo Indian Sagwa Renovator, and Johnson’s Carbolic Salve. At the same time, this is a valuable tool for anyone researching over the counter medicine, drug use, or popular culture during the 19th century. Here’s the description from the Smithsonian website:

The Smithsonian Institution began to collect objects related to health and medicine in 1881. It first obtained examples of patent medicines in 1930, acquiring packages of Haarlem Oil (or Dutch Drops), Dr. John Hooper’s Female Pills, and Roche’s Herbal Embrocation.  Since then the Smithsonian’s collection of patent medicines has expanded to over 4,000 products, dating from the 19th century to the present day. The online exhibit “Balm of America” features examples from this collection, found in the Division of Medicine and Science at the National Museum of American History.  Each entry includes a photo of the object, the product’s name, maker’s name, place of manufacture, and a date range.  Ingredients and therapeutic claims are included when indicated on the product packaging.

Physical vs. technological diagnosis

In modern medicine, physicians are greatly aided in diagnosis by new machines and technology. Undoubtedly these devices provide more accurate and detailed information than the old, low-tech methods, which usually leads to better treatment for the patient. However, some vestiges of the old methods are still in use and still provide valuable information for a doctor. These methods of physical diagnosis, such as using a stethoscope and taking your pulse or blood pressure, have remained cornerstones of a clinical examination.

Ancient Egyptians, Chinese, and Greeks all recognized the value of reading the pulse to diagnosis illnesses. Many cultures identified various qualities in the feeling of the pulse and correlated those to illnesses. As early as 2600 BC the Chinese recorded observations of the effect of excess salt in the body leading to a faster pulse. However it would be many years until the the circulation of the blood and the workings of the circulatory system were understood. In 1616, William Harvey’s experiments proved that the blood flowed in a circular fashion through the body and was pumped by the heart, not the arteries themselves.

Johannes Kepler (1571-1630), famous for his study of astronomy and mathematics, was also the first person who recorded counting the pulse by the minute. Previously, analyzing the pulse rate was a strictly qualitative method. Skilled physicians may have been able to identify high blood pressure and other illnesses using this method, but it was a precise art. Using a standard unit of measurement allowed physicians to compare data and create charts for normal and abnormal readings and their meanings. By the early 170os, counting the pulse by the minute had become common. As the century progressed, more attention was paid to the quantity of pulse, not the quality.

With the increased use of pulse data, physicians began to invent devices to read and record the pulse. The first of such machines was invented in 1555 by Joseph Struthus. He pioneered the idea of representing the pulse graphically, but lacked the technology for a sophisticated device. After 1616, with new understanding about the circulatory system, the importance of stress on the heart, and a rise in quantitative readings, doctors also became interested in measuring the pressure of the blood to diagnosis disease. Physicians had discovered that one could measure the pressure inside the artery by measuring the amount of outside pressure it took to stop the flow of blood. In the late 1700s and early 1800s many cumbersome devices were made that applied measured pressure to the artery in the wrist and recoded the pulse response on a rotating cylinder covered with smoked paper.

In 1896, Italian Scipione Riva-Rocci invented a simple instrument that obstructed the artery using an inflatable arm cuff. A vertical meter filled with mercury measured the amount of pressure in the cuff. The next year, two physicians used this devise to monitor eight surgical patients while they were under anesthesia. At the turn of the century, blood pressure measurement began to reach a significant level in the United States for the first time.

The last major discovery in the measurement of blood pressure came from a young Russian doctor serving a military hospital. Using a pressure cuff, Nicolai Sergeivich Korotkoff began using a stethoscope to listen to the pulse under the cuff and noticed several distinct sounds as the pressure was released. In 1905, after further study, he was able to identify the sounds of maximal and minimal pressure of the artery. In 1927, the United States Bureau of Standards recognized this method as the most accurate for the measurement of blood pressure and it became a routine procedure in medical examination.

As a side note, the evolution of methods to measure blood pressure also illustrates medicines inter connectivity with broader science and discovery. For example, the use of pulse in diagnosis was greatly aided by standardized time. Our understanding of blood circulation was increased in 1839 when physicists determined a law for the behavior of  liquids flowing in tubes. The modern blood pressure cuff was not possible until Charles Goodyear had invented vulcanized rubber in 1839 and John Dunlap had refined it to make a pneumatic tire in 1887.

The upcoming exhibit “Tools of the Trade: Medical Instrumentation” will address the evolution of a variety of medical tools and procedures.

19th century doctors in the U.S.

During the late 1800s, many advances in medical knowledge and technology resulted in dramatic changes to many areas of the profession. The two major advances were the acceptance of the germ theory of disease and the use of anesthesia during surgery. These two discoveries, in combination with continued research of the human body and the development of specialized tools, led to major transformations in our concepts of illness, methods of treatment, and hygienic practices at the turn of the 20th century.

Medical practice during most of the 19th century was carried out in private homes or occasionally in a private doctor’s office. During the Industrial Revolution, hospitals in large cities had a reputation for being dirty. Many people contracted diseases from staying in the hospital because doctors did not know how disease spread. Therefore, those that could afford it called a doctor to their homes. Doctors usually worked in a wide geographic area, and were expected to treat everything from toothaches to stomach aches, fevers, and sick livestock. As the century progressed, knowledge of specific parts of the body increased, specialized tools and procedures were developed, and gradually, doctors became specialized in broad areas of medicine.

In the 1800s, most doctors traveled by foot or horseback to patients’ homes. In this practice, a physician was limited in the number of tools and drugs he could use to those items that could fit in a hand-held case or saddlebags. It is understandable that the quality of care might be poor due to the combination of limited tools and the expectation of the doctor to treat a wide variety of aliments. Examinations and treatment were also done in a patient’s home.  Examinations could include general observation of the patient’s body, the use of a stethoscope to the chest, lungs, and digestive track, or the analysis of blood or urine. A popular treatment was bleeding. There were many ways to bleed a patient and it was often done repeatedly over a short period of time. A single blood-letting could consist of 12 ounces, which is about 6% of an adults total volume of blood. Other principle treatments included specific diet instructions, rest, baths, massage, blistering specific areas of the body, sweating, enemas, purging through use of diuretics and emetics like ipecac, and prescriptions such as anti-inflammation creams or herbal pills.

blood-letting device

Surgery could also be carried out in a patient’s home. Anesthesia was not widely used until the end of the century, so most surgeries were limited to surface areas of the body and a patient’s tolerance of pain. Early anesthesia consisted ether or chloroform, and carried some risk of asphyxiation. An additional risk in this type of surgical setting is infection. In the United States, anti-septic was not common until the turn of the century, so the risk of infection from any surgery was high.

Like today, 19th century doctors usually charged their patients per procedure. They may have charged more for emergency evening visits or charged less for the treatment of a child. One major difference from doctors of today is that 19th century doctors were not often paid with cash, but rather “in kind” with whatever produce, services, or goods were available to the patient. This was especially true for rural or frontier doctors.

Find out about 20th century doctors, dentists, and surgeons by clicking on the “Doctors and Dentists Offices” link under the Exhibits tab.

Early pharmaceutical tools

Before the industrial production of medicines, all syrups, ointments, pills, and salves were made by hand- often by a trained apothecary or pharmacist. Over the years, specialized tools were developed to assist these specialists in making a variety of medicines. Mortars and pestles were used to grind, pulverize, and mix herbs and powdered medicines. They were made of a wide variety of materials including stone, iron, marble, brass, bronze, glass, or even wood. Mortars in the 17th century were highly decorated. Their use in pharmacies was so central that they became a symbol of the trade. In the mid-1800s, “drug mills” replaced the labor-intensive mortar and pestle to grind or mix large quantities of medicine. Some pharmacists may have used domestic spice or coffee grinders for smaller jobs as well.

brass mortar and pestle with pill tile

Pile tiles, like the one seen behind the mortar and pestle in the photograph, were often made of wedgewood or crockery. They were well glazed to provide a smooth and impermeable surface. Some of these tiles were marked for measurement, others were decorated with professional seals or advertisements. They could be used in conjunction with a small spatula to mix, roll, or divide small quantities of pills.

Pills, or lozenges, have been made by hand (with or without pill tiles) for centuries. For example, the ancient Greeks on the island of Lemnos mixed herbs and other medicines with packed earth to make pills. They might have made these pills with their hands or used specialized tools. Another common and simple technique for ingesting powdered medicine was to dissolve or suspend it in water. However, this was unpopular because many solutions had a bad taste.

“Pill machines” were invented in Germany around 1750 to assist pharmacists in making several standardized lozenges at a time. Some machines made as many as 50 pills, but the more popular machines made 18 to 24. At first they were made of wood, but later parts of the machine were made out of brass. After the pill “mass” was created by mixing the medicine with other non-active ingredients, it would be rolled out to an even thickness using the flat board and a rolling pin. The pharmacist could then use the grooved parts of the machine to mold the pills into rounded shapes on both sides. When the mass dried, the pills could be broken along the lines of the grooves, creating smooth, identical forms. Some pharmacists also used a “pill finisher” to coat the lozenges with gelatin, varnish, or fine talc powder. Pill machines were made and used in the United States until about 1930.

wood and brass pill machine

These pharmaceutical tools are part of the upcoming exhibit entitled “Tools of the Trade.” In this exhibit, visitors will learn more about the evolution of medical instruments from denistry, optometry, gynecology, otolaryngology, and other fields. It opens in Winter 2009!

Abraham Lincoln’s DNA

February 12, 2009 marks the 200th anniversary of Abraham Lincoln’s birth. Many events are planned to honor him and bring attention to new historical research about his life. Some of this new research has focused on the former President’s health and DNA.

The speculation centers around Mr. Lincoln’s remarkable physique. He was an extraordinarily tall man for the early 19th century, measuring 6 feet 4 inches. His arms, hands, legs, and feet also seemed to be elongated. In addition, he was very thin throughout his life. Historical evidence suggests that he weighed about 170 pounds. In the 1960s, medical specialists speculated that he had Marfan syndrome. This hereditary disorder usually affects the growth of the lungs, eyes, bones, and most importantly, the heart. However, Lincoln was not known to have problems with his heart, or in any of the other areas.

Another speculation is that Mr. Lincoln had spinocerebellar ataxia type 5, which has been discovered in his descendants. This hereditary disorder affects coordination and could explain historical accounts of the former President’s clumsy gait-like walk.

Recently, cardiologist John G. Sotos posed a new theory that Lincoln’s unusual build was caused by multiple endocrine neoplasia type 2- a genetic disorder that causes the growth of tumors and usually affects the thyroid. In many cases, the tumors are cancerous. Sotos speculates that Lincoln may have been dying of cancer when he was assassinated in April 1865.  (Lincoln was 56 years old when John Wilkes Booth shot him in the back of the head at close range, damaging vital brain tissue and causing a severe hemorrhage.)

The research into Lincoln’s health gets complicated here because these diseases can be diagnosed through simple DNA tests. The plethora of bloodied clothing, skull fragments, and pieces of hair that have been saved from his assassination are all possible sources for DNA that can be tested. However, the testing may cause part of the artifact to be destroyed, any many curators and artifact owners are not willing to take that risk.

Beyond the destruction of Lincoln artifacts, there is the ethical question about whether researchers have the right to analyze the former President’s DNA and make the findings public. Would it set a precedent that could possibly erode the privacy of other historical figures? Is it worth the risk…? When Lincoln’s body was moved to a more secure burial site over 100 years ago, his last living son requested that his father’s body be left in peace. Since then, curators and researchers have cited this request as evidence of the Lincoln family’s wishes.

On the other side, historians and those who suffer from these diseases would like to have conclusive answers. Almost every other aspect of this famous President’s life has been researched extensively. If the DNA evidence proves Lincoln did have a genetic defect, others with disabilities could site his success as encouragement.

It’s a tricky question…

You can learn about the health of other U.S. Presidents in our virtual exhibit “When the President is the Patient” which is posted below.

When the President is the Patient, by Brian Brennan

After clicking on the start button (center of the splashcast screen), roll your cursor over the bottom of the presentation to activate controls. This is a self guided Tour.