The introduction of the Pavlovian method into clinical work with human beings by Horsley Gantt1-3has put at our disposal an important parameter of the neuropsychiatric examination. The introduction into psychiatric therapy of new and highly specialized drugs makes further development of this method of examination desirable, for the following reason: Most of the new drugs were developed and selected in the laboratory on the basis of their ability to influence conditional responses in animals, but were applied in the clinic on an empirical basis to patients whose illnesses are defined along Kraepelinian diagnostic or Freudian psychodynamic lines. It is very unlikely, however, that a relatively simple measure, such as drug therapy, could directly or specifically influence such complicated syndromes, but much more likely that, as in the animal experiments determining their selection, these drugs would influence such relatively simple, objectively definable parameters of mental illness as excitation, inhibition,