1. Determination of various forms of axrenalin like substances adrenalin, dehydroform, chromogens together with the study of bioligical sympathic and parasympathic activity of the blood at physiological and certain pathological states of the organism offers the known idea about the tonus and reactance of various branches of the vegetative nervous system. 2. The content of adrenalin like substances and the level of biological activity of the blood vary in broad intervals in norm and in pathology as well. 3. The high level of adrenalin like substances and sympathic activity of the blood is noticed in cases of diseases, accompanied with painful syndrome, at certain forms of diencephalic pathology and at Addisons disease. 4. Low level of adrenalin like substances of the blood was observed at myasthenia. An improvement in the patients states, patients suffering from myasthenia, caused by proserine, is connected not only with changes in acetylcholine exchange, but also with the rise in level of adrenalin like substances and with the increase in sympathetic activity of the blood. 5. In each individual case is necessary to separate the primary pathological process and compensation phenomena homeostatic reactions, intended for preservation of relative constancy of inner medium.