I feel that the greatest reward for doing is the opportunity to do more.

My life is pretty well at peace, and the profession is more of an avocation. It's a calling, if you like, rather than a job. I do what I feel impelled to do, as an artist would.

What you see in living systems, and in genetic systems, is that the genes are already there, having arisen in the course of time, and when they are needed they become activated. If they had to be invented, the time would be too late.

It is always with excitement that I wake up in the morning wondering what my intuition will toss up to me, like gifts from the sea. I work with it and rely on it. It's my partner.

I feel that the greatest reward for doing is the opportunity to do more.

Risks, I like to say, always pay off. You learn what to do, or what not to do.

Reply when questioned on the safety of the polio vaccine he developed: It is safe, and you can't get safer than safe.