AN ACOUSTIC DEPTH ALARM DEVICE TO MONITOR VERTICAL TRANSLATION OF THE MICROSCOPE STAGE - A PRACTICAL OPTICAL DISECTOR, SELECTOR AND UNBIASED BRICK FOR ROUTINE LIGHT-MICROSCOPY

A description is given of a simple device, which, when attached to the fine adjustment vernier of a regular light microscope, alerts the operator by sound to the vertical distances travelled by the microscope stage without losing visual contact with the specimen. Depending on whether the depth calibration is deemed to be accurate or not, this device can be used as a practical stereological disector or a selector in routine light microscopy, or as an unbiased brick in confocal microscopy.