midnight
According to Burke , constant attempts had been made to achieve Fu-Manchu 's purpose , and had only been frustrated by his -LRB- Burke 's -RRB- wakefulness . There was every probability that another attempt would be made to-night . Any one who has been forced by circumstance to undertake such a vigil as this will be familiar with the marked changes -LRB- corresponding with phases of the earth 's movement -RRB- which take place in the atmosphere , at midnight , at two o'clock , and again at four o'clock . During those fours hours falls a period wherein all life is at its lowest ebb , and every Physician is aware that there is a greater likelihood of a patient 's passing between midnight and four A. M. , than at any other period during the cycle of the hours . To-night I became specially aware of this lowering of vitality , and now , with the night at that darkest phase which precedes the dawn , an indescribable dread , such as I had known before in my dealings with the Chinaman , assailed me , when I was least prepared to combat it . The stillness was intense . Then : `` Here it is ! ''