A measuring device for analyzing a lubricant of a bearing. The measuring device has an electromagnetic radiation emitter, a receiving element and a test area that is arranged between the emitter and the receiving element. The measuring device allows for current information on the condition of the lubricant in the bearing to be obtained. At least some sections of the test area are inside the bearing and the receiving element supplies a spectrum of electromagnetic radiation captured by the test area. Also, a bearing and a seal for the bearing and a method for detecting and monitoring the condition of the lubricant of a bearing.