"We are not to be discouraged by the smallness of the means, but to remember that the greatest results are often produced by the accumulation of small effects."

"We are like a judge who has to sum up and deliver judgment, not on the evidence of witnesses, but on the arguments of counsel."

"We are not here concerned with the first origin of life."

"I have been much struck by the fact that the more I have read about the subject, the less I have understood it."

"One day, on looking at an orchid, I was struck with the idea that the structure of the flower was adapted to the visits of insects."