midnight
Roof and walls were white ; light was supplied from bulbs overhead . The atmosphere was fresh , though the means of ventilation were not visible . Here again they trod on rubber . Christopher Craig had caused the tunnel to be constructed as soon as he realised the truth about his malady ; but it was primarily the outcome of a joking remark by Handyside after a midnight summons in mid-winter . It should be said here that at first Handyside had demurred becoming his neighbour 's physician , but growing friendship with the lonely man had gradually eliminated his scruples . The tunnel had been a costly undertaking , the more so owing to the hurrying of its construction , but Christopher would have told you that its existence had saved his life on more than one occasion . The secret of the doors , by the way , was known only to himself and Caw , Dr. Handyside and Marjorie .