Pasteurization is one of the most famous French inventions.
Louis Pasteur was a chemist and microbiologist who invented a process to kill microorganisms in wine, beer and milk.
He discovered that this would occur when these liquids were heated at certain temperatures, for a specific duration of time, followed by rapid cooling.
Pasteur was granted a patent for his invention and his process became known as "pasteurization". This innovation derived from his belief that germs could cause illness and disease.
At the time, many microorganisms were too small to be seen by microscopes and his germ theory was considered controversial.
In fact, sanitizing as a means to prevent the spread of disease was non-existent.Even among medical practitioners, few doctors washed their hands or even cleaned their equipment.
As a result of his invention, Pasteur convinced the medical community to practice sanitizing their hands, equipment and facilities in order to prevent the spread of disease.
Pasteur made many discoveries in the fields of chemistry and microbiology. He discovered the molecular basis for the asymmetry of certain crystals and also contributed further French inventions by inventing and patenting the first vaccines for rabies and anthrax.
Laennec invented the stethoscope as a means of improving the method by which physicians listened to a patient's chest in order to diagnosis heart and respiratory conditions.
At the time, doctors were using percussion (direct auscultation). They would press their ear against the patient's chest and tap their fingers on the torso.
But there were problems with direct auscultation. If patients were overweight their fat "sound-proofed" their chests; and it was also embarrassing for women patients to have a doctor placing his head on their breasts and tapping their torsos.
Laennec was a flautist and understood acoustics. He realized the simple fact that sound could be amplified as in scratching a pin at one of end of a length of wood and hearing the sound by placing your ear at the other end.
The physician rolled some paper to make a cylinder and listened to a patient's heart. He could distinctly hear the heart pumping with a clarity that was not possible using direct auscultation.
Laennec built a three piece hollow wooden cylinder that looked like a trumpet and called it a stethoscope from stethos meaning chest, and skopos meaning examination.
This new method for direct listening is known as "mediate auscultation".
Photo credit: Barky