Scientific Method in Action the Strange Case of Beriberi
In 1887 a strange nerve disease attacked the people in the Dutch East Indies. The disease was
beriberi. Symptoms of the disease included weakness and loss of appetite; victims often died of heart
failure. Scientists thought the disease might be caused by bacteria. They injected chickens with
bacteria from the blood of patients with beriberi. The injected chickens became sick. However, so did
a group of chickens that were not injected with bacteria.
One of the scientists, Dr. Eijkman, noticed something. Before the experiment, all the chickens had
eaten whole-grain rice, but during the experiment, the chickens were fed polished rice. Dr. Eijkman
researched this interesting case and found that polished rice lacked thiamine, a vitamin necessary for
good health.
1. State the Problem
A disease was found in the Dutch East Indies and was harming people.
2. What was the hypothesis?
The disease was caused by bacteria.
3. How was the hypothesis tested?
By injecting the bacteria to a group of chickens.
4. Should the hypothesis be supported or rejected based on the experiment?
This should be rejected as the controlled variable isn’t the same throughout the whole test.
5. What should be the new hypothesis and how would you test it?
If I were to test a hypothesis it would be about whether the disease was caused by the lack of
thiamine or not. I would feed a group of chickens polished rice and another with whole grain
rice and write down the results.
How Penicillin Was Discovered
In 1928, Sir Alexander Fleming was studying Staphylococcus bacteria growing in culture dishes. He
noticed that a mold called Penicillium was also growing in some of the dishes. A clear area existed
around the mold because all the bacteria that had grown in this area had died. In the culture dishes
without the mold, no clear areas were present.
Fleming hypothesized that the mold must be producing a chemical that killed the bacteria. He
decided to isolate this substance and test it to see if it would kill bacteria. Fleming transferred the
mold to a nutrient broth solution. This solution contained all the materials the mold needed to grow.
After the mold grew, he removed it from the nutrient broth. Fleming then added the nutrient broth
in which the mold had grown to a culture of bacteria. He observed that the bacteria died which was
later used to develop antibiotics used to treat a variety of diseases.
6. Identify the problem.
There wasn’t a substance known to kill bacteria, at the time.
7. What was Fleming's hypothesis?
The mold was killing the bacteria.
8. How was the hypothesis tested?
He isolated the substance and transferred it to a nutrient broth solution which made the
mold grow and then he added it to a culture of bacteria and observed that the bacteria was
killed there.
9. Should the hypothesis be supported or rejected based on the experiment?
It should be supported based on the experiment.
10. This experiment lead to the development of what major medical advancement?
The creation of penicillin