four o'clock
Carefully set aside was the blood which he had drawn from Seabury 's veins , allowed to stand till the serum separated out from the clot . Next he pipetted it into a centrifuge tube and centrifuged it at high speed , some sixteen thousand revolutions , until the serum was perfectly clear , with no trace of a reddish tint , nor even cloudy . After that he drew off the serum into a little tube , covered it with a layer of a substance called toluol from another sterile pipette , and finally placed it in an incubator at a temperature of about ninety-eight . It was well along toward four o'clock when he paused as if some mental alarm clock had awakened him to another part of the plan of action he had laid out . `` Walter , '' he remarked , hastily doffing his stained old laboratory coat , `` I think we 'd better drop around to the Vanderveer . '' Curious as I had been at the preparations he was making in the laboratory , I was still glad at even the suggestion of something that my less learned mind could understand and it was not many seconds before we were on our way . Through the lobby of the famous new hostelry we slowly lounged along , then down a passage into the tea room , where , in the center of a circle of quaint little wicker chairs and tables , was a glossy dancing floor .