Polonium subjects were chosen because experimenters wanted persons who had not been exposed to polonium either through work or accident. All subjects had incurable diseases. Excretion of polonium was followed, and an autopsy was conducted at that time on the deceased patient to determine which organs absorbed the polonium. Patients' ages ranged from 'early thirties' to 'early forties'. The experiments were described in Chapter 3 of Biological Studies with Polonium, Radium, and Plutonium, National Nuclear Energy Series, Volume VI-3, McGraw-Hill, New York, 1950. Not specified is the isotope under study, but at the time polonium-210 was the most readily available polonium
Polonium and sources of neutrons and alpha particles. This radioactivity makes polonium dangerously toxic. Po is an alpha emitter that has a half-life of 138.4 days; it decays directly to its stable daughter isotope, Pb. A milligram (5 curies) of Po emits about as many alpha particles per second as 5 grams of Ra. A few curies (1 curie equals 37 gigabecquerels, 1 Ci = 37 GBq) of Po emit a blue glow which is caused by ionisation of the surrounding air. About one in 100,000 alpha emissions causes an excitation in the nucleus which then results in the emission of