Loss of blood from the human body has been a cause of concern from very ancient times, giving rise to attempts to understand blood flow better. The circulation of the blood was first discovered by an English physician in 1628. The initial attempt to correct blood loss by transfusion of blood of another was seen to be successful for the first time in 1665 AD, when the British physician Richard Lower successfully transfused blood, between dogs. However, the success of the experiment in dogs, made many believe that blood transfusion between humans was also possible. For more info visit www.guidebooktolife.com/lesser-known-facts-about-human-blood-groups-including-the-rarest-blood-groupin-the-world