“Everything is poisonous, nothing is poisonous, it is all a matter of dose.”

The true worth of an experimenter consists in his pursuing not only what he seeks in his experiment, but also what he did not seek.

The mental never influences the physical. It is always the physical that modifies the mental, and when we think that the mind is diseased, it is always an illusion.

Science increases our power in proportion as it lowers our pride.

When we meet a fact which contradicts a prevailing theory, we must accept the fact and abandon the theory, even when the theory is supported by great names and generally accepted.

The terrain is everything; the germ is nothing.

The joy of discovery is certainly the liveliest that the mind of man can ever feel.

The experimenter who does not know what he is looking for will not understand what he finds.

The better educated we are and the more acquired information we have, the better prepared shall we find our minds for making great and fruitful discoveries.

A man of science rises ever, in seeking truth; and if he never finds it in its wholeness, he discovers nevertheless very significant fragments; and these fragments of universal truth are precisely what constitutes science.

We must never make experiments to confirm our ideas, but simply to control them.

Effects vary with the conditions which bring them to pass, but laws do not vary. Physiological and pathological states are ruled by the same forces; they differ only because of the special conditions under which the vital laws manifest themselves.

Priestley said that each discovery we make shows us many others that should be made.

With the aid of these active experimental sciences man becomes an inventor of phenomena, a real foreman of creation; and under this head we cannot set limits to the power that he may gain over nature through future progress of the experimental sciences.

The minds that rise and become really great are never self-satisfied, but still continue to strive.

But while I accept specialization in the practice, I reject it utterly in the theory of science.

Science does not permit exceptions.

Do not use poisonous words against anyone, for words wound more fatally than even arrows.

Alchemize what tries to poison you, into what inevitably heals you.

Poisoned food will look like nourishment to someone who is starving. The same principle applies to abusive relationships.

Malice swallows the greatest part of its own venom.

Water is the medicine for indigestion; it is invigorating when the food that is eaten is well digested; it is like nectar when drunk in the middle of a dinner; and it is like poison when taken at the end of a meal.

Even bees, the little almsmen of spring bowers, know there is richest juice in poison-flowers.

How well you treat the wicked people, they don’t give up their wickedness. They derive pleasure in hurting others. A serpent made to drink milk, it ejects poison only.

Science is the great antidote to the poison of enthusiasm and superstition.