A constant 24/7/365 monitoring of vital body measurements. Imagine how public health would change if we continuously monitored blood glucose in real time. Imagine how your behavior would change if you could, in near real time, detect the presence or absence of biochemicals or toxins in your blood picked up from your environment. (You might conclude: "I'm not going back there!") This data could serve both as a warning system and also as a personal base upon which to diagnose illness and prescribe medicines.