Scientists in the U-S have developed dried blood that can be stored for years to be used for accidents, emergencies or operations. The blood is made from donated human blood, which has a normal shelf life of 42 days. So far tests on the new product have been successful. Doctors in Sweden have completed three years of trials on patients and said there were no side effects. Blood is in constant demand around the world—a lack of donors and a short shelf life means there is a constant shortage. The development has been hailed as the medical equivalent of landing on the moon.