time must cooeperate.  The satisfaction of our thirst in a tea-room may be a trivial illustration of such a final effect, but it is clear that in order to produce this ultimate mental effect of satisfying the thirst, thousands of economic processes must have preceded.  To bring the tea and the sugar and the lemon to the table, the porcelain cup and the silver spoon, wage-earners, manufacturers and laborers, exporters, importers, storekeepers, salesmen, and customers had to cooeperate.  Among such part processes which serve the economic achievement are always many which succeed only if they produce characteristic effects in human minds.  The propaganda which the storekeeper makes, for instance, his display and his posters, serve the economic interplay by psychical effects without themselves satisfying any ultimate economic demand.  They must attract the passer-by or impress the reader or stimulate his impulse to buy, and through all this they reach an end which is in itself not final, as no human desire to read advertisements exists.  When the salesman influences the customer to buy something which may later help to satisfy a real economic demand, the art of his suggestive words secures a mental effect which again is in itself not ultimate.  If the manufacturer influences his employees to work with more attention or with greater industry, or if the community stirs up the desire for luxury or the tendency to saving, we have mental effects which are of economic importance without being really ultimate economic effects.

As far as these effects are necessary and justified stages leading to the ultimate satisfaction of economic demands, it certainly is the duty of applied psychology to bring psychological experience and exact methods into their service.  We emphasize the necessary and justified character of these steps, as it is evident that psychological methods may be made use of also by those who aim toward mental effects which are unjustified and which are not necessary for the real satisfaction of valuable demands.  Psychological laws can also be helpful in fraudulent undertakings or in advertisements for unfair competition.  The psychotechnical scientist cannot be blamed if the results of his experiments are misused for immoral purposes, just as the chemist is not responsible if chemical knowledge is applied to the construction of anarchistic bombs.  But while psychology, as we have emphasized before, cannot from its own point of view determine the value of the end, the psychologist as a human being is certainly willing to cooeperate only where the soundness and correctness of the ends are evident from the point of view of social welfare.