"The microscope is our most important tool in the fight against disease."

"The microscope is the most important instrument in bacteriology."

"I have often been misunderstood, but that has never deterred me from my path."

"The existence of microorganisms as a cause of disease is no longer a matter of theory, but a demonstrated fact."

"The study of bacteria has opened up a new world of knowledge, and it is a world full of wonders."