Abstract
Reactions produced by experience fall into two great groups. The larger group consists of the reactions of those individuals whose mental mechanisms are accurately attuned to the demands of life; the smaller group is composed of the reactions of those unfortunates who are unable to adjust or adapt their mental processes to the ever-increasing complexities of civilization. The individuals forming the former group are called normal. Kræpelin termed the mal-adjustments of those in the latter group the “biogenic psychoses.”