Sentence:  ... I was concerned to hear from your brother that Mrs. Wills' health had prevented her accompanying you to Sixt as usual. It must have thrown a <WSD>damp</WSD> over your autumn excursion ... 
Meaning of the word marked with <WSD> tags:  Dejection or depression; something that spoils a positive emotion (such as enjoyment, satisfaction, expectation or courage) or a desired activity.