1. Diffusion and autolysis of the pigmentation and metamorphic principles of the pituitary proceed together after death of the animal.
2. Rise in temperature increases the rate of diffusion and autolytic action.
3. The presence of other principles and of autolytic products does not affect the response of the pigmentation principle but the activity of the metamorphic principle is reduced by diffused and autolytic products. As these products increase a point is reached when the presence of the metamorphic principle cannot be detected.
4. Diffusion and autolysis are responsible in a large measure for the variations in the metamorphic and pigmentation results obtained by the administration of anterior and posterior lobe productss.