A bird treated thus, for example, these second-level centres being still intact while the hemispheres are removed, retains his normal appearance, being quite able to stand upon his feet, to fly, walk, etc.

His reflexes are also unimpaired and his inner physiological processes; but it soon becomes noticeable that his mental operations are limited very largely to sensations.

He sees his food as usual, but does not remember its use, and makes no attempt to eat it.

He sees other birds, but does not respond to their advances.

He seems to have forgotten all his education, to have lost all the meanings of things, to have practically no intelligence.