"The isolation of disease-causing microorganisms is the first step towards controlling them."

"The greatest obstacle to progress is not ignorance, but the illusion of knowledge."

"As soon as I had found the tubercle bacillus, I found it also in the sputum of phthisical patients."

"The results of my investigations have been confirmed by many other workers."

"The search for truth is the noblest endeavor of man."