Decree reversed. The board adopted the findings of the single member that the claimant's injury, sustained while dancing at a Christmas party given by her employer at the hotel where she worked as a waitress, and at which attendance was optional, did not arise out of and in the course of her employment. The decision dismissing the claim was affirmed. The question being one of fact and the findings being supported by evidence and free from legal error, the judge's entry of a decree awarding compensation was wrong. In all its essentials the case is governed by Moore's Case, 330 Mass. 1.