Quote by Hugo de Vries

"Mutation is the only source of novelty in evolution"

"Nature does not proceed by leaps"

"The origin of species lies in the nature of variation"

"Evolution is a process of continuous change"

"Never underestimate the power of a good laugh."

"Laughter is the best medicine."

"A good laugh is the best medicine."

"Laughter is contagious and wonderful."