If it is impossible to judge merit and guilt in the field of natural science, then it is not possible in any field, and historical research becomes an idle, empty activity.

If you want to become a chemist, you will have to ruin your health. If you don't ruin your health studying, you won't accomplish anything these days in chemistry. Liebig's advice to Kekulé.

Chocolate is a perfect food, as wholesome as it is delicious, a beneficent restorer of exhausted power...it is the best friend of those engaged in literary pursuits.

The secret of all those who make discoveries is that they regard nothing as impossible.

Chemistry, in its application to animals and vegetables. Endeavours jointly with physiology to enlighten us respecting the mysterious processes and sources of organic life.

Observation is like a piece of glass, which, as a mirror, must be very smooth, and must be very carefully polished, in order that it may reflect the image pure and undistorted.

The more fodder, the more flesh; the more flesh, the more manure; the more manure, the more grain.

A fact acquires its true and full value only through the idea which is developed from it.

The progress of mankind is due exclusively to the progress of natural sciences, not to morals, religion or philosophy.

In the progressive growth of astronomy, physics or mechanical science was developed, and when this had been, to a certain degree, successfully cultivated, it gave birth to the science of chemistry.

In this apparatus is nothing new but its simplicity and thorough trustworthiness. On his revolutionary method of organic analysis.

I saw no way out but to dive right in, to a good book.

Believe in your purposes. Define yourself endlessly.

It may be in the cultural particularities of people — in their oddities — that some of the most instructive revelations of what it is to be generically human are to be found.

Just as riches are an impediment to virtue in the wicked, so in the good they are an aid of virtue.

Your role is to do and say the things that need to be done and said from your unique perspective.

clocks in disagreement are worse than no clock at all.

If people get to the end of the record, then that is a treat.

Pffft, English. Who needs that? I'm never going to England.

Cary Grant was one of the most marvelous men I've ever met.

Love all creatures! Love everything that has life!