19th Century to Early 20th Century
One of the first medical devices was the ophthalmoscope invented by a German scientist, Hermann von Helmholz, in 1850. The ophthalmoscope allows the interior of the eye to be viewed.
In 1855, Manuel García invented the laryngoscope, which uses a mirror to see the inside of the throat and the larynx.
At about the same time, Willhelm Roentgen, a professor of physics in Bavaria, discovered that radiation can penetrate solid objects of low density. This led to the invention of x-ray, which allowed physicians to view the inside of the body without surgery. X-rays became popular in World War II. They were used to diagnose pneumonia, pleurisy, tuberculosis, and to help doctors before surgery. The biochemical assay was also developed during this period to be used as a diagnostic tool for diabetes, kidney disease, anemia, diphtheria, and tuberculosis.
Technology also made a great impact on medical procedures and allowed for complex surgical procedures to be developed. In 1927, the respirator was introduced. In 1939, the first heart-lung bypass machine was introduced.
The origin of physical therapy can be traced back to Elizabeth Kenny, an Australia nurse, who used hot packs for treament of polio and muscle rehabilitation in the early 20th century. Hot pack procedures were shown to reduce residual polio paralysis from 85% to 15%.