1. #1 The strange case of Beriberi
Question: What caused the disease Beriberi?
Claim/Argument: Polished rice had a lack of the vitamin, thymine, which caused the disease beriberi.
Evidence/Concrete Details: 1) chickens injected with bacteria became sick 2) chickens NOT injected with bacteria became sick 3) symptoms of disease included weakness, loss of appetite, & heart failure 4) before experiment chickens were fed whole-grain rice 5) during experiment chickens were fed polished rice which lacked thymine
Reasoning/Commentary: Lack of the vitamin, thymine, was causing beriberi. Since both groups of chickens (those injected with bacteria and those not injected) became sick, the bacteria was not the cause of beriberi. Prior to the experiment, all the chickens were fed whole-grain rice and did not become sick. During the experiment all the chickens were fed polished rice and became sick. Polished rice lacks thymine, an important vitamin necessary for good health. Thus, it was the lack of thymine that caused the symptoms of the disease beriberi.

2. #2 – How Penicillin was discovered
Question: What killed the bacteria?
Claim/Argument: Penicillin killed the bacteria.
Evidence/Concrete Details: 1) mold (Penicillin) was also growing in some of the bacteria dishes 2) clear area existed around the mold 3) no clear area in the dishes without the mold 4) bacteria died when exposed to the nutrient broth that grew the mold
Reasoning/Commentary: The mold, Penicillin, killed the bacteria. When bacteria was grown in culture dishes that had the mold, they was a clear area around the mold. When there was no mold present in the dishes, there was no clear area. The clear area around the mold meant that the bacteria had died. Also, when the bacteria was exposed to the nutrient broth that grew the mold they also died. Thus, it was the mold, Penicillin, that killed the bacteria and eventually became the antibiotics we use today to treat a variety of illnesses.