I ask myself whether I am mad.  As I was walking just now in the sun by the riverside, doubts as to my own sanity arose in me; not vague doubts such as I have had hitherto, but precise and absolute doubts.  I have seen mad people, and I have known some who have been quite intelligent, lucid, even clear-sighted in every concern of life, except on one point.  They spoke clearly, readily, profoundly on everything, when suddenly their thoughts struck upon the breakers of their madness and broke to pieces there, and were dispersed and foundered in that furious and terrible sea, full of bounding waves, fogs and squalls, which is called madness.

I certainly should think that I was mad, absolutely mad, if I were not conscious, did not perfectly know my state, if I did fathom it by analyzing it with the most complete lucidity.  I should, in fact, be a reasonable man who was laboring under a hallucination.  Some unknown disturbance must have been excited in my brain, one of those disturbances which physiologists of the present day try to note and to fix precisely, and that disturbance must have caused a profound gulf in my mind and in the order and logic of my ideas.  Similar phenomena occur in the dreams which lead us through the most unlikely phantasmagoria, without causing us any surprise, because our verifying apparatus and our sense of control has gone to sleep, while our imaginative faculty wakes and works.  Is it not possible that one of the imperceptible keys of the cerebral finger-board has been paralyzed in me?  Some men lose the recollection of proper names, or of verbs or of numbers or merely of dates, in consequence of an accident.  The localization of all the particles of thought has been proved nowadays; what then would there be surprising in the fact that my faculty of controlling the unreality of certain hallucinations should be destroyed for the time being!

I thought of all this as I walked by the side of the water.  The sun was shining brightly on the river and made earth delightful, while it filled my looks with love for life, for the swallows, whose agility is always delightful in my eyes, for the plants by the riverside, whose rustling is a pleasure to my ears.

By degrees, however, an inexplicable feeling of discomfort seized me.  It seemed to me as if some unknown force were numbing and stopping me, were preventing me from going farther and were calling me back.  I felt that painful wish to return which oppresses you when you have left a beloved invalid at home, and when you are seized by a presentiment that he is worse.

I, therefore, returned in spite of myself, feeling certain that I should find some bad news awaiting me, a letter or a telegram.  There was nothing, however, and I was more surprised and uneasy than if I had had another fantastic vision.

August 8th. I spent a terrible evening yesterday.  He does not show himself any more, but I feel that he is near me, watching me, looking at me, penetrating me, dominating me and more redoubtable when he hides himself thus, than if he were to manifest his constant and invisible presence by supernatural phenomena.  However, I slept.