Anything written about Abraham Lincoln by someone who didn't personally know him or someone who lived during that time.
Answer:
Koch was able to extract and isolate the bacteria.
Explanation:
Kock was a German bacteriologist responsible for adopting the postulates of Friedrich Gustav Jakob Henle, known today as Postulates of Koch. Through these postulates, he was able to extract and isolate bacteria responsible for diseases, in addition to being able to relate these bacteria to the disease they caused.