1. The methods used in the operation and care of suprarenalectomized dogs are given.
2. The effect of injections of the cortical hormone upon normal and suprarenalectomized dogs is described.
3. Symptoms and chemical studies of suprarenal insufficiency in the dog, following extract withdrawal are described, together with the effects produced by its readministration.
4. The phenomena associated with experimental suprarenal insufficiency are contrasted with those seen in patients with Addison's disease. The identity of the acute symptoms with those of "shock" is pointed out.