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"

"You can't expect to be happy if you're surrounded by mess."

"Health and happiness - these are true wealth"

"How can you live like this? It's like a pigsty!"

"You're going to get sick living like this."