Download How Do We Know That Germs Cause Disease? Since the time of

How Do We Know That Germs Cause Disease?
Since the time of the ancient Greeks, miasma, or bad smelling air, was thought to be the cause of illness. Many foulsmelling observations were used to substantiate this inference. Not until the mid-1800’s were new discoveries made that led to the
development of a new theory, the germ theory (model) of disease.
In the early 1800’s, the Italian farmer, Agostino Bassi, observed the devastation of the local silkworm industry. The worms
were dying after being covered by a fine, white powder. Bassi studied this powder and determined that it was a living, contagious
organism. In 1835 he published his findings and he recommended sanitation practices that saved the silkworm industry. Eventually
this organism was identified as a fungus and named Beauvaria bassina in his honor. Bassi had developed a new theory (model),
the germ theory of disease.
In 1848 a severe outbreak of cholera killed 7,000 Londoners in one month. A local physician, John Snow, analyzed where
people were getting sick and inferred that the water from one particular well was tainted with the cholera germ. When he removed
the handle from the Broad Street water pump, it ended an epidemic in that area.
Louis Pasteur, a French chemist, did some experiments later that reinforced the germ model. In 1862 he demonstrated that if
a beverage like milk is gently heated, the mold and bacteria that normally spoil it would be destroyed. Pasteur concluded that if germs
could infect food, then they could infect the human body too.
Pasteur’s ideas spread across the scientific community and were noticed by the English surgeon, Joseph Lister. At that time,
surgeons still believed in the miasma model of disease. Surgeons aired out their hospitals and operating rooms to make them smell
better, but didn’t bother with washing their hands, or even washing their patients’ wounds. Terrible infections were killing nearly half
of Lister’s patients so he decided to use Pasteur’s ideas to try and save the patients. He used a chemical, carbolic acid, to kill germs
on his patients’ wounds, on his hands, in the air, and on his surgical equipment. In 1867 he announced that he hadn’t lost a single
patient to infection in nine months.
Today, the germ model of disease is widely accepted. Scientists have the technology to magnify and see germs, from
bacteria to viruses. Controlled experiments directly show the causal link between germs and diseases such as chicken pox and
influenza. Many breakthroughs in medicine, like antibiotics and immunizations, have been developed because of our knowledge
about how germs spread and replicate inside plants and animals.
References
Agostino Bassi Bicentenial (1773-1973) by J.R. Porter, in Bacteriological Reviews, Sept. 1973.
http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=413819&blobtype=pdf
LIFE Online: Top 100 Events of the Millennium http://www.life.com/Life/millennium/events/06.html
Polio: Kids Health http://kidshealth.org/parent/infections/bacterial_viral/polio.html
How Do We Know That Germs Cause Disease?
Since the time of the ancient Greeks, miasma, or bad smelling air, was thought to be the cause of illness. Many foulsmelling observations were used to substantiate this inference. Not until the mid-1800’s were new discoveries made that led to the
development of a new theory, the germ theory (model) of disease.
In the early 1800’s, the Italian farmer, Agostino Bassi, observed the devastation of the local silkworm industry. The worms
were dying after being covered by a fine, white powder. Bassi studied this powder and determined that it was a living, contagious
organism. In 1835 he published his findings and he recommended sanitation practices that saved the silkworm industry. Eventually
this organism was identified as a fungus and named Beauvaria bassina in his honor. Bassi had developed a new theory (model),
the germ theory of disease.
In 1848 a severe outbreak of cholera killed 7,000 Londoners in one month. A local physician, John Snow, analyzed where
people were getting sick and inferred that the water from one particular well was tainted with the cholera germ. When he removed
the handle from the Broad Street water pump, it ended an epidemic in that area.
Louis Pasteur, a French chemist, did some experiments later that reinforced the germ model. In 1862 he demonstrated that if
a beverage like milk is gently heated, the mold and bacteria that normally spoil it would be destroyed. Pasteur concluded that if germs
could infect food, then they could infect the human body too.
Pasteur’s ideas spread across the scientific community and were noticed by the English surgeon, Joseph Lister. At that time,
surgeons still believed in the miasma model of disease. Surgeons aired out their hospitals and operating rooms to make them smell
better, but didn’t bother with washing their hands, or even washing their patients’ wounds. Terrible infections were killing nearly half
of Lister’s patients so he decided to use Pasteur’s ideas to try and save the patients. He used a chemical, carbolic acid, to kill germs
on his patients’ wounds, on his hands, in the air, and on his surgical equipment. In 1867 he announced that he hadn’t lost a single
patient to infection in nine months.
Today, the germ model of disease is widely accepted. Scientists have the technology to magnify and see germs, from
bacteria to viruses. Controlled experiments directly show the causal link between germs and diseases such as chicken pox and
influenza. Many breakthroughs in medicine, like antibiotics and immunizations, have been developed because of our knowledge
about how germs spread and replicate inside plants and animals.
References
Agostino Bassi Bicentenial (1773-1973) by J.R. Porter, in Bacteriological Reviews, Sept. 1973.
http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=413819&blobtype=pdf
LIFE Online: Top 100 Events of the Millennium http://www.life.com/Life/millennium/events/06.html
Polio: Kids Health http://kidshealth.org/parent/infections/bacterial_viral/polio.html