— 15 —
the dotted circles indicate that we do not yet know the relative size which should be assigned to them:
A very large group of the insanities conforms to this type. When we endeavour to unravel the causes which have produced the disorder, we find on the one hand a series of mental stresses which are clearly responsible at least for the particular shape the patient's symptoms have assumed. On the other hand we find a series of constitutional peculiarities and physiological disturbances whose importance is so obvious that we may be tempted to ascribe to them the chief part in the causation of the symptoms, and to regard the mental causes as minor agents which have merely provided the symptoms with their surface colouring. For example, to revert to an illustration already given, the irritability of the dyspeptic may show itself mainly in the patient's relations with a certain person, because it is directed into that channel by the existence of certain ideas and emotions. But the prime cause of the irritability is the dyspepsia; the ideas and emotions have merely provided the particular colouring in which it manifests itself. In this example the matter is, of course, simple enough, but in the group of insanities now under consideration the physiological and mental causes are so intricately woven and interwoven that their unravelling is a problem of extreme difficulty,
