Gradualness, gradualness, and gradualness. From the very beginning of your work, school yourself to severe gradualness in the accumulation of knowledge.

The digestive canal is in its task a complete chemical factory. The raw material passes through a long series of institutions in which it is subjected to certain mechanical and, mainly, chemical processing, and then, through innumerable side-streets, it is brought into the depot of the body. Aside from this basic series of institutions, along which the raw material moves, there is a series of lateral chemical manufactories, which prepare certain reagents for the appropriate processing of the raw material.

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 weaker and finally drops to zero.

Do not become archivists of facts. Try to penetrate to the secret of their occurrence, persistently search for the laws which govern them.

It is not accidental that all phenomena of human life are dominated by the search for daily bread - the oldest link connecting all living things, man included, with the surrounding nature.

From the described experiment it is clear that the mere act of eating, the food even not reaching the stomach, determines the stimulation of the gastric glands.