Smith and Bert

 

Earth has been oxygenated for about 2.3 billion to 2.4 billion years, and levels began to creep up at least 2.5 billion years ago, according to a 2007 NASA-funded study. No one knows quite why this lung-friendly gas suddenly became a significant part of the atmosphere, but it's possible that geologic changes on Earth led to oxygen produced by photosynthesizing organisms sticking around, rather than being consumed in geologic reactions, according to the study researchers.

                                                            Discovery Of Oxygen 

Antoine Lavoisier from France gave Oxygen its name

Concentration Of Oxygen (Earth/Atmosphere/Body)

History Of Oxygen Therapy 

Oxygen Toxicity (Bert/Smith Effect)

Pulmonary Toxicity (Lorrain Smith Effect)

Bert Effect (CNS Toxicity)

Snapshot