The history of medicine shows that every important step in the progress of scientific medicine has been followed by development in the corresponding branch of clinical medicine. Among the biologic disciplines physiology is especially closely connected with the clinic. At the close of the last century the physiologists made great progress in the investigation of almost all organs, but physiologic study of the brain remained decidedly backward.
However, during the last three decades there have been great achievements in this branch of physiology. In 1901, Prof. I. P. Pavlov, with many co-workers, began an intensive study of the higher nervous activity in animals by the strictly physiologic method of conditioned reflexes. Great results have been attained in this field of investigation, and many important laws regulating cerebral activity have been discovered by these workers.
The inspiring advances of Pavlov's work stimulated me to elaborate on the method, so that it