Sigmund Freud 
Dream Psychology: Psychoanalysis for Beginners By Sigmund Freud 

The medical profession is justly conservative. Human life should not be considered as the proper material for wild experiments.Conservatism, however, is too often a welcome excuse for lazy minds, loath to adapt themselves to fast changing conditions.Remember the scornful reception which first was accorded to Freud’s discoveries in the domain of the unconscious.