Quantitative work shows clearly that natural selection is a reality, and that, among other things, it selects Mendelian genes, which are known to be distributed at random through wild populations, and to follow the laws of chance in their distribution to offspring. In other words, they are an agency producing variation of the kind which Darwin postulated as the raw material on which selection acts.

My final word, before I'm done, Is "Cancer can be rather fun"- Provided one confronts the tumour with a sufficient sense of humour. I know that cancer often kills, But so do cars and sleeping pills; And it can hurt till one sweats, So can bad teeth and unpaid debts. A spot of laughter, I am sure, Often accelerates one's cure; So let us patients do our bit To help the surgeons make us fit.

There are 400,000 species of beetles on this planet, but only 8,000 species of mammals.

[Children] are taught that it is a virtue to accept statements without adequate evidence, which leaves them a prey to quacks of every kind in later life, and makes it very difficult for them to accept the methods of thought which are successful in science.

We do not know, in most cases, how far social failure and success are due to heredity, and how far to environment. But environment is the easier of the two to improve.

There is no great invention, from fire to flying, which has not been hailed as an insult to some god.

Teleology is like a mistress to a biologist: he cannot live without her but he's unwilling to be seen with her in public.