Ivan Pavlov begins his study of conditioned…

Ivan Pavlov begins his study of conditioned reflex in dogs in 1898.

It is at the Institute of Experimental Medicine that Pavlov carries out his classical experiments on the digestive glands.

Thais is how he will eventually win a Nobel prize.

Pavlov investigates the gastric function of dogs, and later, children, by externalizing a salivary gland so he can collect, measure, and analyze the saliva and what response it has to food under different conditions.

He notices that the dogs tend to salivate before food is actually delivered to their mouths, and sets out to investigate this "psychic secretion", as he calls it.

Pavlov's laboratory houses a full-scale kennel for the experimental animals.

Pavlov is interested in observing their long-term physiological processes.

This requires keeping them alive and healthy in order to conduct chronic experiments, as he calls them.

These are experiments over time, designed to understand the normal functions of animals.

This is a new kind of study, because previously experiments had been “acute,” meaning that the dog went through vivisection which ultimately killed the animal in the process.