(Johannes Muller, 2014). The doctrine of specific nervous energies was his most important contribution to the study of the physiology of behavior. He observed that all nerves carry the same basic message, but we discern that the message of different nerves is not the same. Because of his specific nerve doctrine, experiments were performed directly on the brains of animals, which was done by Pierre Flourens, a French physiologist. This was known as experimental ablation. He later claimed to have found the part of the brain responsible for breathing, heart rate control, purposeful movements, and auditory reflexes. Soon after this experimental ablation was applied to a human brain. This observation led to the demonstration that a portion of the cerebral cortex at the front of the left side of the brain performs the functions necessary for speech. This remains important for understanding the brain. (Behavioral physiology,