While you are experimenting, do not remain content with the surface of things. Don't become a mere recorder of facts, but try to penetrate the mystery of their origin.

When the dog is repeatedly teased with the sight of objects inducing salivary secretion from a distance, the reaction of the salivary glands grows weaker and w…

With each meal, when edible substances find their way into the oral cavity, thick and viscous saliva containing much mucus flows out of these glands.

Thus, the purposeful relationship of phenomena is based on the specificity of the stimuli, that correspond to similarly specific reactions.

Basic research is when I'm doing what I don't know I'm doing.

I love fools' experiments. I am always making them.

'We were told in one lecture that it was possible to immunize against diphtheria and tetanus by the use of chemically treated toxins, or toxoids. And the follo…