On the other hand in the more intense obsessions, where a greater part of the setting is unconscious, has wide ramifications and has become differentiated as an independent autonomous process, the more difficult it is to suppress it and prevent its springing into activity whenever excited by some stimulus (such as an associated idea). In such instances the second method is more efficacious. It is obvious that, so long as the setting to a central idea remains organized and conserved in the unconscious, the corresponding perception and meaning are always liable under favoring conditions (such as fatigue, ill health, etc.) to be switched into consciousness and replace the new formed perception. This means of course a recurrence. Nevertheless medical experience from the beginning of time has shown that this is not necessarily or always the case. The technique, therefore, of the treatment of obsessions will vary from “simple explanations” (Taylor) without preliminary analysis to the more complicated and varying procedures of analysis and re-education in its many forms. _Affects._—Here a word of caution in the interpretation of emotional reactions is necessary. In the building of complexes, as we have seen, an affect becomes linked to an idea through an emotional experience. The recurrence of that idea always involves the recurrence of the affect. It is not a logical necessity that the original experience which occasioned the affect should always be postulated as a continuing subconscious process to account for the affect in association with the idea. It is quite possible, if not extremely probable, that in the simpler types, at least, of the emotional complexes, the association between the idea and affect becomes so firmly established that the conscious idea alone, without the coöperation of a subconscious process, is sufficient to awake the emotion; just as in Pawlow’s dogs the artificially formed association between a tactile stimulus and the salivary glands is sufficient to excite the glands to activity, or as in human beings the idea of a ship by pure association may determine fear and nausea, the sound of running water by the force of association may excite the bladder reflex, or an ocular stimulus the so-called hay fever complex. So in word-association reactions, when a word is accompanied by an affect-reaction the word itself may be sufficient to excite the reaction without assuming that an “unconscious complex has been struck.” The total mechanism of the process we are investigating must be determined in each case for itself.