Optical apparatus with a slide lighting system for detecting a woman's fertile period during her menstrual cycle

In a system for detecting a fertile period during a woman's menstrual cycle from observation of her saliva with an optical apparatus, an improved optical apparatus, comprising:

• an outer tubular body having, at one end, slide-receiving means for receiving a slide, whereby the slide may carry a woman's saliva for an observation, and a diffusing glass for transmitting light to one side of the slide during the observation and, at the opposite end, threads;
• an inner tubular body having a lens system of about 100-fold magnification fixed therein, the inner tubular body being telescopically in the outer tubular body and threaded to the threads thereof for axial movement relative thereto upon relative rotation thereof, whereby to focus the lens system on the saliva on the slide for the observation thereof;
• another tubular body having an open end and an opposite closed end, whereby to hold a battery, a bulb in the open end, and switch means for lighting the bulb with the battery;
• and
• connecting means for connecting the one end of the outer tubular body to the open end of the other tubular body, whereby to provide the light from the bulb to the diffusing glass, slide and lens system for the observation.